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Huang X, Yang S, Zhao J, Yang J, Jiang H, Li S, Wang C, Liu G. Generation and evaluation of Salmonella entericaserovar Choleraesuis mutant strains as a potential live-attenuated vaccine. Vaccine 2024; 42:126262. [PMID: 39197218 DOI: 10.1016/j.vaccine.2024.126262] [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: 04/26/2024] [Revised: 07/02/2024] [Accepted: 08/20/2024] [Indexed: 09/01/2024]
Abstract
BACKGROUND Salmonella entericaserovar Choleraesuis (S.C) is a swine enteric pathogen causing paratyphoid fever, enterocolitis, and septicemia in piglets. S. C is mainly transmitted through the fecal-oral route. Vaccination is an effective strategy for preventing and controlling Salmonella infection. RESULTS Herein, we used CRISPR-Cas9 technology to knockout the virulence regulatory genes, rpoS, and slyA of S. C and constructed the ∆rpoS, ∆slyA, and ∆rpoS ∆slyA strains. The phenotypic characteristics of the mutant strains remained unchanged compared with the parental wild-type strain. In vivo study, unlike the wild-type strain, the ∆slyA and ∆rpoS ∆slyA strains alleviated splenomegaly, colon atrophy, and lower bacterial loads in the spleen, liver, ileum, and colon. These mutant strains survived in Peyer's patches (PPs) and mesenteric lymph nodes (MLN) for up to 15 days post-infection. Furthermore, the immunization of the ∆rpoS ∆slyA strain induced robust humoral and cellular immune responses. CONCLUSIONS Consequently, vaccination with ∆rpoS ∆slyA conferred a high percentage of protection against lethal invasive Salmonella, specifically S. C, in mice. This study provided novel insights into the development of live-attenuated vaccines against the infection of S. C.
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Affiliation(s)
- Xin Huang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Shanshan Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.; Key Laboratory of Veterinary Biological Engineering and Technology, Ministry of Agriculture, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China
| | - Jing Zhao
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Jing Yang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.; Molecular and Cellular Epigenetics (GIGA) and Molecular Biology (TERRA), University of Liege, Belgium
| | - Huazheng Jiang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China
| | - Shuxian Li
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.; College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China
| | - Caiying Wang
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.; Cell Biology and Immunology Group, Wageningen University and Research, Wageningen, the Netherlands
| | - Guangliang Liu
- State Key Laboratory for Animal Disease Control and Prevention, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, China.; College of Veterinary Medicine, Xinjiang Agricultural University, Urumqi, China.
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Kokkinias K, Sabag-Daigle A, Kim Y, Leleiwi I, Shaffer M, Kevorkian R, Daly RA, Wysocki VH, Borton MA, Ahmer BMM, Wrighton KC. Time-resolved multi-omics reveals diverse metabolic strategies of Salmonella during diet-induced inflammation. mSphere 2024:e0053424. [PMID: 39254340 DOI: 10.1128/msphere.00534-24] [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: 06/24/2024] [Accepted: 07/22/2024] [Indexed: 09/11/2024] Open
Abstract
With a rise in antibiotic resistance and chronic infection, the metabolic response of Salmonella enterica serovar Typhimurium to various dietary conditions over time remains an understudied avenue for novel, targeted therapeutics. Elucidating how enteric pathogens respond to dietary variation not only helps us decipher the metabolic strategies leveraged for expansion but also assists in proposing targets for therapeutic interventions. In this study, we use a multi-omics approach to identify the metabolic response of Salmonella enterica serovar Typhimurium in mice on both a fibrous diet and high-fat diet over time. When comparing Salmonella gene expression between diets, we found a preferential use of respiratory electron acceptors consistent with increased inflammation in high-fat diet mice. Looking at the high-fat diet over the course of infection, we noticed heterogeneity in samples based on Salmonella ribosomal activity, which is separated into three infection phases: early, peak, and late. We identified key respiratory, carbon, and pathogenesis gene expressions descriptive of each phase. Surprisingly, we identified genes associated with host cell entry expressed throughout infection, suggesting subpopulations of Salmonella or stress-induced dysregulation. Collectively, these results highlight not only the sensitivity of Salmonella to its environment but also identify phase-specific genes that may be used as therapeutic targets to reduce infection.IMPORTANCEIdentifying novel therapeutic strategies for Salmonella infection that occur in relevant diets and over time is needed with the rise of antibiotic resistance and global shifts toward Western diets that are high in fat and low in fiber. Mice on a high-fat diet are more inflamed compared to those on a fibrous diet, creating an environment that results in more favorable energy generation for Salmonella. We observed differential gene expression across infection phases in mice over time on a high-fat diet. Together, these findings reveal the metabolic tuning of Salmonella to dietary and temporal perturbations. Research like this, which explores the dimensions of pathogen metabolic plasticity, can pave the way for rationally designed strategies to control disease.
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Affiliation(s)
- Katherine Kokkinias
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
| | - Anice Sabag-Daigle
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Yongseok Kim
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Ikaia Leleiwi
- Department of Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Michael Shaffer
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Richard Kevorkian
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Rebecca A Daly
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Vicki H Wysocki
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
| | - Mikayla A Borton
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
| | - Brian M M Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, USA
| | - Kelly C Wrighton
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado, USA
- Department of Cell and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, USA
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Ramezanifard R, Golubeva YA, Palmer AD, Slauch JM. TamAB is regulated by PhoPQ and functions in outer membrane homeostasis during Salmonella pathogenesis. J Bacteriol 2023; 205:e0018323. [PMID: 37728604 PMCID: PMC10601761 DOI: 10.1128/jb.00183-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/12/2023] [Indexed: 09/21/2023] Open
Abstract
Salmonella survive and replicate in macrophages, which normally kill bacteria by exposing them to a variety of harsh conditions and antimicrobial effectors, many of which target the bacterial cell envelope. The PhoPQ two-component system responds to the phagosome environment and induces factors that protect the outer membrane, allowing adaptation and growth in the macrophage. We show that PhoPQ induces the transcription of the tamAB operon both in vitro and in macrophages. The TamA protein is structurally similar to BamA, an essential protein in the Bam complex that assembles β-barrel proteins in the outer membrane, while TamB is an AsmA-family protein implicated in lipid transport between the inner and outer membranes. We show that the Bam machinery is stressed in vitro under low Mg2+, low pH conditions that mimic the phagosome. Not surprisingly, mutations affecting Bam function confer significant virulence defects. Although loss of TamAB alone confers no virulence defect, a tamAB deletion confers a synthetic phenotype in bam mutant backgrounds in animals and macrophages, and in vitro upon treatment with vancomycin or sodium dodecyl sulfate. Mutations affecting YhdP, which functions in partial redundancy with TamB, also confer synthetic phenotypes with bam mutations in the animal, but this interaction is not evident in vitro. Thus, in the harsh phagocytic environment of the macrophage, the outer membrane Bam machinery is compromised, and the TamAB system, and perhaps other PhoPQ-regulated factors, is induced to compensate. It is most likely that TamAB and other systems assist the Bam complex indirectly by affecting outer membrane properties. IMPORTANCE The TamAB system has been implicated in both outer membrane protein localization and phospholipid transport between the inner and outer membranes. We show that the β-barrel protein assembly complex, Bam, is stressed under conditions thought to mimic the macrophage phagosome. TamAB expression is controlled by the PhoPQ two-component system and induced in macrophages. This system somehow compensates for the Bam complex as evidenced by the fact that mutations affecting the two systems confer synthetic phenotypes in animals, macrophages, and in vitro in the presence of vancomycin or SDS. This study has implications concerning the role of TamAB in outer membrane homeostasis. It also contributes to our understanding of the systems necessary for Salmonella to adapt and reproduce within the macrophage phagosome.
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Affiliation(s)
- Rouhallah Ramezanifard
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - Yekaterina A. Golubeva
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - Alexander D. Palmer
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
| | - James M. Slauch
- Department of Microbiology, University of Illinois at Urbana Champaign, Urbana, Illinois, USA
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Liu M, Wang H, Liu Y, Tian M, Wang Z, Shu RD, Zhao MY, Chen WD, Wang H, Wang H, Fu Y. The phospholipase effector Tle1 Vc promotes Vibrio cholerae virulence by killing competitors and impacting gene expression. Gut Microbes 2023; 15:2241204. [PMID: 37526354 PMCID: PMC10395195 DOI: 10.1080/19490976.2023.2241204] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 07/20/2023] [Indexed: 08/02/2023] Open
Abstract
Vibrio cholerae utilizes the Type VI secretion system (T6SS) to gain an advantage in interbacterial competition by delivering anti-prokaryotic effectors in a contact-dependent manner. However, the impact of T6SS and its secreted effectors on physiological behavior remains poorly understood. In this study, we present Tle1Vc, a phospholipase effector in atypical pathogenic V. cholerae E1 that is secreted by T6SS via its interaction with VgrG1E1. Tle1Vc contains a DUF2235 domain and belongs to the Tle1 (type VI lipase effector) family. Bacterial toxicity assays, lipase activity assays and site-directed mutagenesis revealed that Tle1Vc possessed phospholipase A1 activity and phospholipase A2 activity, and that Tle1Vc-induced toxicity required a serine residue (S356) and two aspartic acid residues (D417 and D496). Cells intoxication with Tle1Vc lead to membrane depolarization and alter membrane permeability. Tli1tox-, a cognate immunity protein, directly interacts with Tle1Vc to neutralize its toxicity. Moreover, Tle1Vc can kill multiple microorganisms by T6SS and promote in vivo fitness of V. cholerae through mediating antibacterial activity. Tle1Vc induces bacterial motility by increasing the expression of flagellar-related genes independently of functional T6SS and the tit-for-tat (TFT) response, where Pseudomonas aeruginosa uses its T6SS-H1 cluster to counterattack other offensive attackers. Our study also demonstrated that the physical puncture of E1 T6SS can induce a moderate TFT response, which is essential to the Tle1Vc-mediated strong TFT response, maximizing effector functions. Overall, our study characterized the antibacterial mechanism of phospholipase effector Tle1Vc and its multiple physiological significance.
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Affiliation(s)
- Ming Liu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Heng Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Ying Liu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Miao Tian
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Zhao Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Run-Dong Shu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Meng-Yu Zhao
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Wei-Di Chen
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Hao Wang
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
| | - Hui Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yang Fu
- School of Medicine, Southern University of Science and Technology, Shenzhen, China
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Sobota M, Rodilla Ramirez PN, Cambré A, Rocker A, Mortier J, Gervais T, Haas T, Cornillet D, Chauvin D, Hug I, Julou T, Aertsen A, Diard M. The expression of virulence genes increases membrane permeability and sensitivity to envelope stress in Salmonella Typhimurium. PLoS Biol 2022; 20:e3001608. [PMID: 35389980 PMCID: PMC9017878 DOI: 10.1371/journal.pbio.3001608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 04/19/2022] [Accepted: 03/17/2022] [Indexed: 11/19/2022] Open
Abstract
Virulence gene expression can represent a substantial fitness cost to pathogenic bacteria. In the model entero-pathogen Salmonella Typhimurium (S.Tm), such cost favors emergence of attenuated variants during infections that harbor mutations in transcriptional activators of virulence genes (e.g., hilD and hilC). Therefore, understanding the cost of virulence and how it relates to virulence regulation could allow the identification and modulation of ecological factors to drive the evolution of S.Tm toward attenuation. In this study, investigations of membrane status and stress resistance demonstrate that the wild-type (WT) expression level of virulence factors embedded in the envelope increases membrane permeability and sensitizes S.Tm to membrane stress. This is independent from a previously described growth defect associated with virulence gene expression in S.Tm. Pretreating the bacteria with sublethal stress inhibited virulence expression and increased stress resistance. This trade-off between virulence and stress resistance could explain the repression of virulence expression in response to harsh environments in S.Tm. Moreover, we show that virulence-associated stress sensitivity is a burden during infection in mice, contributing to the inherent instability of S.Tm virulence. As most bacterial pathogens critically rely on deploying virulence factors in their membrane, our findings could have a broad impact toward the development of antivirulence strategies.
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Affiliation(s)
| | | | - Alexander Cambré
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | | | - Julien Mortier
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Théo Gervais
- Biozentrum, University of Basel, Basel, Switzerland
- Swiss Institute of Bioinformatics, Basel, Switzerland
| | | | | | - Dany Chauvin
- Biozentrum, University of Basel, Basel, Switzerland
- Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Isabelle Hug
- Biozentrum, University of Basel, Basel, Switzerland
| | - Thomas Julou
- Biozentrum, University of Basel, Basel, Switzerland
- Swiss Institute of Bioinformatics, Basel, Switzerland
| | - Abram Aertsen
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
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STAT3 and SPI1, may lead to the immune system dysregulation and heterotopic ossification in ankylosing spondylitis. BMC Immunol 2022; 23:3. [PMID: 35065610 PMCID: PMC8783415 DOI: 10.1186/s12865-022-00476-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 01/12/2022] [Indexed: 12/11/2022] Open
Abstract
Objective This study was aimed to identify the biomarkers for diagnosis and reveal the immune microenvironment changes in ankylosing spondylitis (AS). Methods GSE73754 was downloaded for the co-expression network construction and immune cell analyses. Flow cytometric analysis was performed to validate the results of bioinformatics analysis. Gene set enrichment analysis (GSEA) was performed to investigate the potential biological characteristic between different phenotypes. Pearson correlation analysis between the hub genes and the xCell score of immune cell types was performed. Results Signal transducer and activator of transcription 3 (STAT3) and Spi-1 proto-oncogene (SPI1) was identified as the hub genes in the datasets GSE73754. And the t-test showed that the expression level of STAT3 and SPI1 in the GSE73754 was significantly higher in AS and human leukocyte antigen (HLA)-B27(+) groups. Flow cytometric analysis showed that natural killer T cells (NKT) cells were upregulated, while Th1 cells were down-regulated in AS, which was consistent with the results obtained from bioinformatics analysis. STAT3 and SPI1 was correlated with the NKT cells and Th1 cells. Conclusion STAT3 and SPI1 may be a key cytokine receptor in disease progression in AS. Supplementary Information The online version contains supplementary material available at 10.1186/s12865-022-00476-6.
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Marchant P, Carreño A, Vivanco E, Silva A, Nevermann J, Otero C, Araya E, Gil F, Calderón IL, Fuentes JA. "One for All": Functional Transfer of OMV-Mediated Polymyxin B Resistance From Salmonella enterica sv. Typhi Δ tolR and Δ degS to Susceptible Bacteria. Front Microbiol 2021; 12:672467. [PMID: 34025627 PMCID: PMC8131662 DOI: 10.3389/fmicb.2021.672467] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/12/2021] [Indexed: 12/22/2022] Open
Abstract
The appearance of multi-resistant strains has contributed to reintroducing polymyxin as the last-line therapy. Although polymyxin resistance is based on bacterial envelope changes, other resistance mechanisms are being reported. Outer membrane vesicles (OMVs) are nanosized proteoliposomes secreted from the outer membrane of Gram-negative bacteria. In some bacteria, OMVs have shown to provide resistance to diverse antimicrobial agents either by sequestering and/or expelling the harmful agent from the bacterial envelope. Nevertheless, the participation of OMVs in polymyxin resistance has not yet been explored in S. Typhi, and neither OMVs derived from hypervesiculating mutants. In this work, we explored whether OMVs produced by the hypervesiculating strains Salmonella Typhi ΔrfaE (LPS synthesis), ΔtolR (bacterial envelope) and ΔdegS (misfolded proteins and σ E activation) exhibit protective properties against polymyxin B. We found that the OMVs extracted from S. Typhi ΔtolR and ΔdegS protect S. Typhi WT from polymyxin B in a concentration-depending manner. By contrast, the protective effect exerted by OMVs from S. Typhi WT and S. Typhi ΔrfaE is much lower. This effect is achieved by the sequestration of polymyxin B, as assessed by the more positive Zeta potential of OMVs with polymyxin B and the diminished antibiotic's availability when coincubated with OMVs. We also found that S. Typhi ΔtolR exhibited an increased MIC of polymyxin B. Finally, we determined that S. Typhi ΔtolR and S. Typhi ΔdegS, at a lesser level, can functionally and transiently transfer the OMV-mediated polymyxin B resistance to susceptible bacteria in cocultures. This work shows that mutants in genes related to OMVs biogenesis can release vesicles with improved abilities to protect bacteria against membrane-active agents. Since mutations affecting OMV biogenesis can involve the bacterial envelope, mutants with increased resistance to membrane-acting agents that, in turn, produce protective OMVs with a high vesiculation rate (e.g., S. Typhi ΔtolR) can arise. Such mutants can functionally transfer the resistance to surrounding bacteria via OMVs, diminishing the effective concentration of the antimicrobial agent and potentially favoring the selection of spontaneous resistant strains in the environment. This phenomenon might be considered the source for the emergence of polymyxin resistance in an entire bacterial community.
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Affiliation(s)
- Pedro Marchant
- Laboratorio de Genética y Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Alexander Carreño
- Laboratorio de Genética y Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Eduardo Vivanco
- Laboratorio de Genética y Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Andrés Silva
- Laboratorio de Genética y Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Jan Nevermann
- Laboratorio de Genética y Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Carolina Otero
- Escuela de Química y Farmacia, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Eyleen Araya
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Santiago, Chile
| | - Fernando Gil
- Microbiota-Host Interactions and Clostridia Research Group, Universidad Andres Bello, Santiago, Chile.,ANID-Millennium Science Initiative Program-Millennium Nucleus in the Biology of the Intestinal Microbiota, Santiago, Chile
| | - Iván L Calderón
- Laboratorio de RNAs Bacterianos, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
| | - Juan A Fuentes
- Laboratorio de Genética y Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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Meng J, Young G, Chen J. The Rcs System in Enterobacteriaceae: Envelope Stress Responses and Virulence Regulation. Front Microbiol 2021; 12:627104. [PMID: 33658986 PMCID: PMC7917084 DOI: 10.3389/fmicb.2021.627104] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 01/18/2021] [Indexed: 11/13/2022] Open
Abstract
The bacterial cell envelope is a protective barrier at the frontline of bacterial interaction with the environment, and its integrity is regulated by various stress response systems. The Rcs (regulator of capsule synthesis) system, a non-orthodox two-component regulatory system (TCS) found in many members of the Enterobacteriaceae family, is one of the envelope stress response pathways. The Rcs system can sense envelope damage or defects and regulate the transcriptome to counteract stress, which is particularly important for the survival and virulence of pathogenic bacteria. In this review, we summarize the roles of the Rcs system in envelope stress responses (ESRs) and virulence regulation. We discuss the environmental and intrinsic sources of envelope stress that cause activation of the Rcs system with an emphasis on the role of RcsF in detection of envelope stress and signal transduction. Finally, the different regulation mechanisms governing the Rcs system's control of virulence in several common pathogens are introduced. This review highlights the important role of the Rcs system in the environmental adaptation of bacteria and provides a theoretical basis for the development of new strategies for control, prevention, and treatment of bacterial infections.
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Affiliation(s)
- Jiao Meng
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Glenn Young
- Department of Food Science and Technology, University of California, Davis, Davis, CA, United States
| | - Jingyu Chen
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
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Hamed S, Shawky RM, Emara M, Slauch JM, Rao CV. HilE is required for synergistic activation of SPI-1 gene expression in Salmonella enterica serovar Typhimurium. BMC Microbiol 2021; 21:49. [PMID: 33593291 PMCID: PMC7887791 DOI: 10.1186/s12866-021-02110-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/07/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Salmonella enterica serovar Typhimurium is an intestinal pathogen capable of infecting a wide range of animals. It initiates infection by invading intestinal epithelial cells using a type III secretion system encoded within Salmonella pathogenicity island 1 (SPI-1). The SPI-1 genes are regulated by multiple interacting transcription factors. The master regulator is HilD. HilE represses SPI-1 gene expression by binding HilD and preventing it from activating its target promoters. Previous work found that acetate and nutrients synergistically induce SPI-1 gene expression. In the present study, we investigated the role of HilE, nominally a repressor of SPI-1 gene expression, in mediating this response to acetate and nutrients. RESULTS HilE is necessary for activation of SPI-1 gene expression by acetate and nutrients. In mutants lacking hilE, acetate and nutrients no longer increase SPI-1 gene expression but rather repress it. This puzzling response is not due to the BarA/SirA two component system, which governs the response to acetate. To identify the mechanism, we profiled gene expression using RNAseq in the wild type and a ΔhilE mutant under different growth conditions. Analysis of these data suggested that the Rcs system, which regulates gene expression in response to envelope stress, is involved. Consistent with this hypothesis, acetate and nutrients were able to induce SPI-1 gene expression in mutants lacking hilE and the Rcs system. CONCLUSIONS While the exact mechanism is unknown, these results demonstrate the HilE, nominally a repressor of SPI-1 gene expression, can also function as an activator under the growth conditions investigated. Collectively, these results provide new insights regarding SPI-1 gene regulation and demonstrate that HilE is more complex than initially envisioned.
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Affiliation(s)
- Selwan Hamed
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave, Urbana, IL, 61801, USA. .,Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University - Ain Helwan, Helwan, 11795, Egypt.
| | - Riham M Shawky
- Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University - Ain Helwan, Helwan, 11795, Egypt
| | - Mohamed Emara
- Department of Microbiology and Immunology, Faculty of Pharmacy, Helwan University - Ain Helwan, Helwan, 11795, Egypt
| | - James M Slauch
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Christopher V Rao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave, Urbana, IL, 61801, USA.
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