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Lê-Bury P, Echenique-Rivera H, Pizarro-Cerdá J, Dussurget O. Determinants of bacterial survival and proliferation in blood. FEMS Microbiol Rev 2024; 48:fuae013. [PMID: 38734892 PMCID: PMC11163986 DOI: 10.1093/femsre/fuae013] [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: 11/06/2023] [Revised: 04/29/2024] [Accepted: 05/10/2024] [Indexed: 05/13/2024] Open
Abstract
Bloodstream infection is a major public health concern associated with high mortality and high healthcare costs worldwide. Bacteremia can trigger fatal sepsis whose prevention, diagnosis, and management have been recognized as a global health priority by the World Health Organization. Additionally, infection control is increasingly threatened by antimicrobial resistance, which is the focus of global action plans in the framework of a One Health response. In-depth knowledge of the infection process is needed to develop efficient preventive and therapeutic measures. The pathogenesis of bloodstream infection is a dynamic process resulting from the invasion of the vascular system by bacteria, which finely regulate their metabolic pathways and virulence factors to overcome the blood immune defenses and proliferate. In this review, we highlight our current understanding of determinants of bacterial survival and proliferation in the bloodstream and discuss their interactions with the molecular and cellular components of blood.
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Affiliation(s)
- Pierre Lê-Bury
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Université Paris-Saclay, Inserm, CEA, Center for Immunology of Viral, Autoimmune, Hematological and Bacterial Diseases (IMVA-HB/IDMIT), 18 route du Panorama, 92260 Fontenay-aux-Roses, France
| | - Hebert Echenique-Rivera
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
| | - Javier Pizarro-Cerdá
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
- Institut Pasteur, Université Paris Cité, Yersinia National Reference Laboratory, WHO Collaborating Research & Reference Centre for Plague FRA-146, 28 rue du Dr Roux, 75015 Paris, France
| | - Olivier Dussurget
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Yersinia Research Unit, 28 rue du Dr Roux, 75015 Paris, France
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Chumsakul O, Nakamura K, Fukamachi K, Ishikawa S, Oshima T. GeF-seq: A Simple Procedure for Base-Pair Resolution ChIP-seq. Methods Mol Biol 2024; 2819:39-53. [PMID: 39028501 DOI: 10.1007/978-1-0716-3930-6_3] [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: 07/20/2024]
Abstract
Nucleotide sequences recognized and bound by DNA-binding proteins (DBPs) are critical to controlling and maintaining gene expression, replication, chromosome segregation, cell division, and nucleoid structure in bacterial cells. Therefore, determination of the binding sequences of DBPs is important not only to study DBP recognition mechanisms but also to understand the fundamentals of cell homeostasis. While ChIP-seq analysis appears to be an effective way to determine DBP binding sites on the genome, the resolution is sometimes not sufficient to identify the sites precisely. Here we introduce a simple and effective method named Genome Footprinting with high-throughput sequencing (GeF-seq) to determine binding sites of DBPs with single base-pair resolution. GeF-seq detects binding sites of DBPs as sharp peaks and thus makes it possible to identify the recognition sequence in each "binding peak" more easily and accurately compared to the common ChIP-seq.
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Affiliation(s)
- Onuma Chumsakul
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan
- Basic Research and Development Division, Rohto Pharmaceutical Co., Ltd., Kyoto, Japan
- Graduate School of Science, Technology and Innovation, Kobe University, Noda, Kobe, Japan
| | - Kensuke Nakamura
- Division of Informatics, Bioengineering and Bioscience, Maebashi Institute of Technology, Maebashi, Gunma, Japan
| | - Kazuki Fukamachi
- Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Shu Ishikawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
- Graduate School of Science, Technology and Innovation, Kobe University, Noda, Kobe, Japan.
| | - Taku Oshima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan.
- Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama, Japan.
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Lu K, Li Y, Chen R, Yang H, Wang Y, Xiong W, Xu F, Yuan Q, Liang H, Xiao X, Huang R, Chen Z, Tian C, Wang S. Pathogenic mechanism of Vibrio vulnificus infection. Future Microbiol 2023; 18:373-383. [PMID: 37158065 DOI: 10.2217/fmb-2022-0243] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023] Open
Abstract
Vibrio vulnificus is a fatal, opportunistic human pathogen transmitted through the consumption of raw/undercooked seafood or direct contact. V. vulnificus infection progresses rapidly and has severe consequences; some cases may require amputation or result in death. Growing evidence suggests that V. vulnificus virulence factors and regulators play a large role in disease progression, involving host resistance, cellular damage, iron acquisition, virulence regulation and host immune responses. Its disease mechanism remains largely undefined. Further evaluation of pathogenic mechanisms is important for selecting appropriate measures to prevent and treat V. vulnificus infection. In this review, the possible pathogenesis of V. vulnificus infection is described to provide a reference for treatment and prevention.
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Affiliation(s)
- Kun Lu
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Yang Li
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Rui Chen
- Department of Orthopedics, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Hua Yang
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Yong Wang
- Hemodialysis Center, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Wei Xiong
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Fang Xu
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Qijun Yuan
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Haihui Liang
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Xian Xiao
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Renqiang Huang
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Zhipeng Chen
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Chunou Tian
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
| | - Songqing Wang
- Department of Neurosurgery, First Naval Hospital of Southern Theater Command, Zhanjiang, 524000, China
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Targeting Virulence Genes Expression in Vibrio vulnificus by Alternative Carbon Sources. Int J Mol Sci 2022; 23:ijms232315278. [PMID: 36499602 PMCID: PMC9737408 DOI: 10.3390/ijms232315278] [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: 11/10/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/11/2022] Open
Abstract
Vibrio vulnificus is an opportunistic human pathogen causing self-limiting gastroenteritis, life-threatening necrotizing soft tissue infection, and fulminating septicaemia. An increasing rate of infections has been reported worldwide, characterized by sudden onset of sepsis and/or rapid progression to irreversible tissue damage or death. Timely intervention is essential to control the infection, and it is based on antibiotic therapy, which does not always result in the effective and rapid blocking of virulence. Inhibitors of essential virulence regulators have been reported in the last years, but none of them has been further developed, so far. We aimed to investigate whether exposure to some carbon compounds, mostly easily metabolizable, could result in transcriptional down-regulation of virulence genes. We screened various carbon sources already available for human use (thus potentially easy to be repurposed), finding some of them (including mannitol and glycerol) highly effective in down-regulating, in vitro and ex-vivo, the mRNA levels of several relevant -even essential- virulence factors (hlyU, lrp, rtxA, vvpE, vvhA, plpA, among others). This paves the way for further investigations aiming at their development as virulence inhibitors and to unveil mechanisms explaining such observed effects. Moreover, data suggesting the existence of additional regulatory networks of some virulence genes are reported.
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Liu S, Fan M, Xu JX, Yang LJ, Qi CC, Xia QR, Ge JF. Exosomes derived from bone-marrow mesenchymal stem cells alleviate cognitive decline in AD-like mice by improving BDNF-related neuropathology. J Neuroinflammation 2022; 19:35. [PMID: 35130907 PMCID: PMC8822863 DOI: 10.1186/s12974-022-02393-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 01/19/2022] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Alzheimer's disease (AD) is a neurodegenerative disease characterized by a progressive decline in cognitive ability. Exosomes derived from bone-marrow mesenchymal stem cells (BMSC-exos) are extracellular vesicles that can execute the function of bone-marrow mesenchymal stem cells (BMSCs). Given the versatile therapeutic potential of BMSC and BMSC-exos, especially their neuroprotective effect, the aim of this study was to investigate the potential effect of BMSC-exos on AD-like behavioral dysfunction in mice and explore the possible molecular mechanism. METHODS BMSC-exos were extracted from the supernatant of cultured mouse BMSCs, which were isolated from the femur and tibia of adult C57BL/6 mice, purified and sorted via flow cytometry, and cultured in vitro. BMSC-exos were identified via transmission electron microscopy, and typical marker proteins of exosomes were also detected via Western blot. A sporadic AD mouse model was established by intracerebroventricular injection of streptozotocin (STZ). Six weeks later, BMSC-exos were administered via lateral ventricle injection or caudal vein injection lasting five consecutive days, and the control mice were intracerebroventricularly administered an equal volume of solvent. Behavioral performance was observed via the open field test (OFT), elevated plus maze test (EPM), novel object recognition test (NOR), Y maze test (Y-maze), and tail suspension test (TST). The mRNA and protein expression levels of IL-1β, IL-6, and TNF-α in the hippocampus were measured via quantitative polymerase chain reaction (qPCR) and Western blot, respectively. Moreover, the protein expression of Aβ1-42, BACE, IL-1β, IL-6, TNF-α, GFAP, p-Tau (Ser396), Tau5, synaptotagmin-1 (Syt-1), synapsin-1, and brain-derived neurotrophic factor (BDNF) in the hippocampus was detected using Western blot, and the expression of GFAP, IBA1, Aβ1-42 and DCX in the hippocampus was measured via immunofluorescence staining. RESULTS Lateral ventricle administration, but not caudal vein injection of BMSC-exos improved AD-like behaviors in the STZ-injected mouse model, as indicated by the increased number of rearing, increased frequency to the central area, and increased duration and distance traveled in the central area in the OFT, and improved preference index of the novel object in the NOR. Moreover, the hyperactivation of microglia and astrocytes in the hippocampus of the model mice was inhibited after treatment with BMSC-exos via lateral ventricle administration, accompanied by the reduced expression of IL-1β, IL-6, TNF-α, Aβ1-42, and p-Tau and upregulated protein expression of synapse-related proteins and BDNF. Furthermore, the results of the Pearson test showed that the preference index of the novel object in the NOR was positively correlated with the hippocampal expression of BDNF, but negatively correlated with the expression of GFAP, IBA1, and IL-1β. Apart from a positive correlation between the hippocampal expression of BDNF and Syt-1, BDNF abundance was found to be negatively correlated with markers of glial activation and the expression of the inflammatory cytokines, Aβ1-42, and p-Tau, which are characteristic neuropathological features of AD. CONCLUSIONS Lateral ventricle administration, but not caudal vein injection of BMSC-exos, can improve AD-like behavioral performance in STZ-injected mice, the mechanism of which might be involved in the regulation of glial activation and its associated neuroinflammation and BDNF-related neuropathological changes in the hippocampus.
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Affiliation(s)
- Sen Liu
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Anhui, 230032, Hefei, People's Republic of China
- The Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, Hefei, China
| | - Min Fan
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Anhui, 230032, Hefei, People's Republic of China
- The Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, Hefei, China
| | - Jing-Xian Xu
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Anhui, 230032, Hefei, People's Republic of China
- The Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Medical University, Hefei, China
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, Hefei, China
| | - Long-Jun Yang
- Chaohu Clinical Medical College, Anhui Medical University, Hefei, China
| | - Cong-Cong Qi
- Neurodevelopmental Laboratory, Fudan University, Shanghai, China
| | - Qing-Rong Xia
- Department of Pharmacy, Hefei Fourth People's Hospital, Anhui Mental Health Center, 316 Huangshan Road, Hefei, 230032, China.
- Psychopharmacology Research Laboratory, Anhui Mental Health Center, Hefei, China.
- Clinical Pharmacy, Affiliated Psychological Hospital of Anhui Medical University, Hefei, China.
| | - Jin-Fang Ge
- School of Pharmacy, Anhui Medical University, 81 Meishan Road, Anhui, 230032, Hefei, People's Republic of China.
- The Key Laboratory of Anti-Inflammatory and Immune Medicine, Ministry of Education, Anhui Medical University, Hefei, China.
- Anhui Provincial Laboratory of Inflammatory and Immunity Disease, Anhui Institute of Innovative Drugs, Hefei, China.
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Ziegler CA, Freddolino PL. The leucine-responsive regulatory proteins/feast-famine regulatory proteins: an ancient and complex class of transcriptional regulators in bacteria and archaea. Crit Rev Biochem Mol Biol 2021; 56:373-400. [PMID: 34151666 DOI: 10.1080/10409238.2021.1925215] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Since the discovery of the Escherichia coli leucine-responsive regulatory protein (Lrp) almost 50 years ago, hundreds of Lrp homologs have been discovered, occurring in 45% of sequenced bacteria and almost all sequenced archaea. Lrp-like proteins are often referred to as the feast/famine regulatory proteins (FFRPs), reflecting their common regulatory roles. Acting as either global or local transcriptional regulators, FFRPs detect the environmental nutritional status by sensing small effector molecules (usually amino acids) and regulate the expression of genes involved in metabolism, virulence, motility, nutrient transport, stress tolerance, and antibiotic resistance to implement appropriate behaviors for the specific ecological niche of each organism. Despite FFRPs' complexity, a significant role in gene regulation, and prevalence throughout prokaryotes, the last comprehensive review on this family of proteins was published about a decade ago. In this review, we integrate recent notable findings regarding E. coli Lrp and other FFRPs across bacteria and archaea with previous observations to synthesize a more complete view on the mechanistic details and biological roles of this ancient class of transcription factors.
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Affiliation(s)
- Christine A Ziegler
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter L Freddolino
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI, USA.,Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI, USA
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Faucher C, Mazana V, Kardacz M, Parthuisot N, Ferdy JB, Duneau D. Step-Specific Adaptation and Trade-Off over the Course of an Infection by GASP Mutation Small Colony Variants. mBio 2021; 12:e01399-20. [PMID: 33436427 PMCID: PMC7845629 DOI: 10.1128/mbio.01399-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 11/17/2020] [Indexed: 11/20/2022] Open
Abstract
During an infection, parasites face a succession of challenges, each decisive for disease outcome. The diversity of challenges requires a series of parasite adaptations to successfully multiply and transmit from host to host. Thus, the pathogen genotypes that succeed during one step might be counterselected in later stages of the infection. Using the bacterium Xenorhabdus nematophila and adult Drosophila melanogaster flies as hosts, we showed that such step-specific adaptations, here linked to GASP (i.e., growth advantage in stationary phase) mutations in the X. nematophila master gene regulator lrp, exist and can trade off with each other. We found that nonsense lrp mutations had lowered the ability to resist the host immune response, while all classes of mutations in lrp were associated with a decrease in the ability to proliferate during early infection. We demonstrate that reduced proliferation of X. nematophila best explains diminished virulence in this infection model. Finally, decreased proliferation during the first step of infection is accompanied by improved proliferation during late infection, suggesting a trade-off between the adaptations to each step. Step-specific adaptations could play a crucial role in the chronic phase of infections in any disease organisms that show similar small colony variants (SCVs) to X. nematophilaIMPORTANCE Within-host evolution has been described in many bacterial diseases, and the genetic basis behind the adaptations has stimulated a lot of interest. Yet, the studied adaptations are generally focused on antibiotic resistance and rarely on the adaptation to the environment given by the host, and the potential trade-offs hindering adaptations to each step of the infection are rarely considered. Those trade-offs are key to understanding intrahost evolution and thus the dynamics of the infection. However, understanding these trade-offs supposes a detailed study of host-pathogen interactions at each step of the infection process, with an adapted methodology for each step. Using Drosophila melanogaster as the host and the bacterium Xenorhabdus nematophila, we investigated the bacterial adaptations resulting from GASP mutations known to induce the small colony variant (SCV) phenotype positively selected within the host over the course of an infection, as well as the trade-off between step-specific adaptations.
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Affiliation(s)
- Christian Faucher
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Vincent Mazana
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Marion Kardacz
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Nathalie Parthuisot
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - Jean-Baptiste Ferdy
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
| | - David Duneau
- CNRS, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Université Toulouse 3 Paul Sabatier, Toulouse, France
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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A MARTX Toxin rtxA Gene Is Controlled by Host Environmental Signals through a CRP-Coordinated Regulatory Network in Vibrio vulnificus. mBio 2020; 11:mBio.00723-20. [PMID: 32723914 PMCID: PMC7387792 DOI: 10.1128/mbio.00723-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A MARTX toxin, RtxA, is an essential virulence factor of many pathogens, including Vibrio species. H-NS and HlyU repress and derepress, respectively, rtxA expression of a life-threatening pathogen, Vibrio vulnificus. We found that Lrp directly activates rtxA independently of H-NS and HlyU, and leucine inhibits the Lrp-mediated activation of rtxA. Furthermore, we demonstrated that CRP represses rtxA but derepresses in the presence of exogenous glucose. CRP represses rtxA not only directly by binding to upstream of rtxA but also indirectly by repressing lrp and hlyU. This is the first report of a regulatory network comprising CRP, Lrp, H-NS, and HlyU, which coordinates the rtxA expression in response to environmental signals such as leucine and glucose during infection. This elaborate regulatory network will enhance the fitness of V. vulnificus and contribute to its successful infection within the host. A multifunctional autoprocessing repeats-in-toxin (MARTX) toxin plays an essential role in the virulence of many pathogens, including a fulminating human pathogen Vibrio vulnificus. H-NS and HlyU repress and derepress expression of the MARTX toxin gene rtxA in V. vulnificus, respectively. However, little is known about other regulatory proteins and environmental signals involved in rtxA regulation. In this study, we found that a leucine-responsive regulatory protein (Lrp) activates rtxA by binding directly and specifically to the rtxA promoter, PrtxA. Phased hypersensitivity resulting from DNase I cleavage of the PrtxA regulatory region suggests that Lrp probably induces DNA bending in PrtxA. Lrp activates PrtxA independently of H-NS and HlyU, and leucine inhibits Lrp binding to PrtxA and reduces the Lrp-mediated activation. Furthermore, a cyclic AMP receptor protein (CRP) represses PrtxA, and exogenous glucose relieves the CRP-mediated repression. Biochemical and mutational analyses demonstrated that CRP binds directly and specifically to the upstream region of PrtxA, which presumably alters the DNA conformation in PrtxA and thus represses rtxA. Moreover, CRP represses expression of lrp and hlyU by binding directly to their upstream regions, forming coherent feed-forward loops with Lrp and HlyU. In conclusion, expression of rtxA is controlled by a regulatory network comprising CRP, Lrp, H-NS, and HlyU in response to changes in host environmental signals such as leucine and glucose. This collaborative regulation enables the elaborate expression of rtxA, thereby enhancing the fitness and pathogenesis of V. vulnificus during the course of infection.
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Xu Y, Tang Y, Wang N, Liu J, Cai X, Cai H, Li J, Tan G, Liu R, Bai L, Zhang L, Wu H, Zhang B. Transcriptional regulation of a leucine-responsive regulatory protein for directly controlling lincomycin biosynthesis in Streptomyces lincolnensis. Appl Microbiol Biotechnol 2020; 104:2575-2587. [DOI: 10.1007/s00253-020-10381-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/06/2020] [Accepted: 01/16/2020] [Indexed: 12/19/2022]
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Hernández-Cabanyero C, Lee CT, Tolosa-Enguis V, Sanjuán E, Pajuelo D, Reyes-López F, Tort L, Amaro C. Adaptation to host in Vibrio vulnificus, a zoonotic pathogen that causes septicemia in fish and humans. Environ Microbiol 2019; 21:3118-3139. [PMID: 31206984 DOI: 10.1111/1462-2920.14714] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 06/10/2019] [Accepted: 06/10/2019] [Indexed: 12/18/2022]
Abstract
Vibrio vulnificus is a siderophilic pathogen spreading due to global warming. The zoonotic strains constitute a clonal-complex related to fish farms that are distributed worldwide. In this study, we applied a transcriptomic and single gene approach and discover that the zoonotic strains bypassed the iron requirement of the species thanks to the acquisition of two iron-regulated outer membrane proteins (IROMPs) involved in resistance to fish innate immunity. Both proteins have been acquired by horizontal gene transfer and are contributing to the successful spreading of this clonal-complex. We have also discovered that the zoonotic strains express a virulent phenotype in the blood of its main susceptible hosts (iron-overloaded humans and healthy eels) by combining a host-specific protective envelope with the common expression of two toxins (VvhA and RtxA1), one of which (RtxA1) is directly involved in sepsis. Finally, we found that both IROMPs are also present in other fish pathogenic species and have recently been transmitted to the phylogenetic lineage involved in human primary sepsis after raw seafood ingestion. Together our results highlight the potential hazard that the aquaculture industry poses to public health, which is of particular relevance in the context of a warming world.
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Affiliation(s)
| | - Chung-Te Lee
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | | | - Eva Sanjuán
- ERI-Biotecmed, University of Valencia, Dr. Moliner, 50, 46100, Valencia, Spain
| | - David Pajuelo
- ERI-Biotecmed, University of Valencia, Dr. Moliner, 50, 46100, Valencia, Spain
| | - Felipe Reyes-López
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Lluis Tort
- Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Carmen Amaro
- ERI-Biotecmed, University of Valencia, Dr. Moliner, 50, 46100, Valencia, Spain
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The Leucine-Responsive Regulatory Protein Lrp Participates in Virulence Regulation Downstream of Small RNA ArcZ in Erwinia amylovora. mBio 2019; 10:mBio.00757-19. [PMID: 31138749 PMCID: PMC6538786 DOI: 10.1128/mbio.00757-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Fire blight disease continues to plague the commercial production of apples and pears despite more than a century of research into disease epidemiology and disease control. The causative agent of fire blight, Erwinia amylovora coordinates turning on or off specific virulence-associated traits at the appropriate time during disease development. The development of novel control strategies requires an in-depth understanding of E. amylovora regulatory mechanisms, including regulatory control of virulence-associated traits. This study investigates how the small RNA ArcZ regulates motility at the transcriptional level and identifies the transcription factor Lrp as a novel participant in the regulation of several virulence-associated traits. We report that ArcZ and Lrp together affect key virulence-associated traits through integration of transcriptional and posttranscriptional mechanisms. Further understanding of the topology of virulence regulatory networks can uncover weak points that can subsequently be exploited to control E. amylovora. Erwinia amylovora causes the devastating fire blight disease of apple and pear trees. During systemic infection of host trees, pathogen cells must rapidly respond to changes in their environment as they move through different host tissues that present distinct challenges and sources of nutrition. Growing evidence indicates that small RNAs (sRNAs) play an important role in disease progression as posttranscriptional regulators. The sRNA ArcZ positively regulates the motility phenotype and transcription of flagellar genes in E. amylovora Ea1189 yet is a direct repressor of translation of the flagellar master regulator, FlhD. We utilized transposon mutagenesis to conduct a forward genetic screen and identified suppressor mutations that increase motility in the Ea1189ΔarcZ mutant background. This enabled us to determine that the mechanism of transcriptional activation of the flhDC mRNA by ArcZ is mediated by the leucine-responsive regulatory protein, Lrp. We show that Lrp contributes to expression of virulence and several virulence-associated traits, including production of the exopolysaccharide amylovoran, levansucrase activity, and biofilm formation. We further show that Lrp is regulated posttranscriptionally by ArcZ through destabilization of lrp mRNA. Thus, ArcZ regulation of FlhDC directly and indirectly through Lrp forms an incoherent feed-forward loop that regulates levansucrase activity and motility as outputs. This work identifies Lrp as a novel participant in virulence regulation in E. amylovora and places it in the context of a virulence-associated regulatory network.
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