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Huang M, Liu M, Liu J, Wang M, Jia R, Zhu D, Chen S, Zhao X, Yang Q, Wu Y, Zhang S, Gao Q, Huang J, Ou X, Mao S, Tian B, Sun D, Cheng A. Evaluation of the immunoprotection efficacy of Riemerella anatipestifer fur-deficient mutant as an attenuated vaccine. Poult Sci 2022; 102:102450. [PMID: 36621099 PMCID: PMC9841290 DOI: 10.1016/j.psj.2022.102450] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 12/10/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Riemerella anatipestifer (R. anatipestifer, RA) is an infectious pathogen that causes septicemia and polyserositis in ducks. Our previous studies showed that RA CH-1 ∆fur was significantly attenuated in ducklings, which highlights the potential of this strain as a live attenuated vaccine. In this study, it was shown that infection with 109 CFU of the fur mutant did not cause any clinical symptoms or significant histological lesions in 3-day-old ducklings and that the bacteria were readily cleared by the host within 3 d. Compared with the nonvaccinated group, the group inoculated with the mutant strain RA CH-1 ∆fur exhibited protection of ducklings against a high-dose (2.28 × 1010 CFU) challenge with the wild-type strain RA CH-1. Moreover, the average body weights and body weight gains of the Δfur-inoculated group were not significantly affected by the challenge. Further analysis revealed that RA CH-1 ∆fur elicited higher IgY titers and that the serum antibody levels persisted for at least 49 d after immunization. Overall, our study showed that RA CH-1 ∆fur is a safe and effective vaccine candidate that is expected to play an important role in RA CH-1 infection prevention in the duck industry.
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Affiliation(s)
- Mi Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Jiajun Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Dekang Zhu
- Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Juan Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Xumin Ou
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Sai Mao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Bin Tian
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Di Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan 611130, PR China.
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2
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Sevilla E, Bes MT, Peleato ML, Fillat MF. Fur-like proteins: Beyond the ferric uptake regulator (Fur) paralog. Arch Biochem Biophys 2021; 701:108770. [PMID: 33524404 DOI: 10.1016/j.abb.2021.108770] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/12/2021] [Accepted: 01/17/2021] [Indexed: 10/22/2022]
Abstract
Proteins belonging to the FUR (ferric uptake regulator) family are the cornerstone of metalloregulation in most prokaryotes. Although numerous reviews have been devoted to these proteins, these reports are mainly focused on the Fur paralog that gives name to the family. In the last years, the increasing knowledge on the other, less ubiquitous members of this family has evidenced their importance in bacterial metabolism. As the Fur paralog, the major regulator of iron homeostasis, Zur, Irr, BosR and PerR are tightly related to stress defenses and host-pathogen interaction being in many cases essential for virulence. Furthermore, the Nur and Mur paralogs largely contribute to control nickel and manganese homeostasis, which are cofactors of pivotal proteins for host colonization and bacterial redox homeostasis. The present review highlights the main features of FUR proteins that differ to the canonical Fur paralog either in the coregulatory metal, such as Zur, Nur and Mur, or in the action mechanism to control target genes, such as PerR, Irr and BosR.
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Affiliation(s)
- Emma Sevilla
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - M Teresa Bes
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - M Luisa Peleato
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - María F Fillat
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.
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Swain B, Powell CT, Curtiss R. Pathogenicity and immunogenicity of Edwardsiella piscicida ferric uptake regulator (fur) mutations in zebrafish. FISH & SHELLFISH IMMUNOLOGY 2020; 107:497-510. [PMID: 33176201 DOI: 10.1016/j.fsi.2020.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 10/22/2020] [Accepted: 10/31/2020] [Indexed: 06/11/2023]
Abstract
Edwardsiella piscicida is the etiological agent of edwardsiellosis in fish and causes severe economic losses in global aquaculture. Vaccination would be the most effective method to prevent infectious diseases and their associated economic losses. The ferric uptake regulator (Fur) is an important transcriptional global regulator of Gram-negative bacteria. In this study, we examined the regulatory function of Fur in E. piscicida. We designed a strain that displays features of the wild-type virulent strain of E. piscicida at the time of immunization to enable strains first to effectively colonize lymphoid tissues and then to exhibit a regulated delayed attenuation in vivo to preclude inducing disease symptoms. Regulated delayed attenuation in vivo is based on the substitution of a tightly regulated araC ParaBAD cassette for the promoter of the fur gene such that expression of this gene is dependent on arabinose provided during growth. Thus, following E. piscicida mutant colonization of lymphoid tissues, the Fur protein ceases to be synthesized due to the absence of arabinose such that attenuation is gradually manifest in vivo to preclude induction of diseases symptoms. We deleted the promoter, including all sequences that interact with activator or repressor proteins, for the fur gene, and substituted the improved araC ParaBAD cassette to yield an E. piscicida strain with the ΔPfur170:TT araC ParaBADfur deletion-insertion mutation (χ16012). Compared to the wild-type strain J118, χ16012 exhibited retarded growth and enhanced siderophore production in the absence of arabinose. mRNA levels of Fur-regulated genes were analyzed in iron deplete or replete condition in wild-type and fur mutant strains. We observed zebrafish immunized with χ16012 showed better colonization and protection compared to the Δfur (χ16001). Studies showed that E. piscicida strain χ16012 is attenuated and induces systemic and mucosal IgM titer in zebrafish. In addition, we found an increase in transcript levels of tnf-α, il-1β, il-8 and ifn-γ in different tissues of zebrafish immunized with χ16012 compared to the unimmunized group. We conclude that, E. piscicida with regulated delayed attenuation could be an effective immersion vaccine for the aquaculture industry.
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Affiliation(s)
- Banikalyan Swain
- University of Florida, Department of Infectious Diseases & Immunology, College of Veterinary Medicine, Gainesville, FL, 32608, USA.
| | - Cole T Powell
- University of Florida, Department of Infectious Diseases & Immunology, College of Veterinary Medicine, Gainesville, FL, 32608, USA
| | - Roy Curtiss
- University of Florida, Department of Infectious Diseases & Immunology, College of Veterinary Medicine, Gainesville, FL, 32608, USA
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Abstract
This chapter provides an overview of current knowledge of how anaerobic bacteria protect themselves against nitrosative stress. Nitric oxide (NO) is the primary source of this stress. Aerobically its removal is an oxidative process, whereas reduction is required anaerobically. Mechanisms required to protect aerobic and anaerobic bacteria are therefore different. Several themes recur in the review. First, how gene expression is regulated often provides clues to the physiological function of the gene products. Second, the physiological significance of reports based upon experiments under extreme conditions that bacteria do not encounter in their natural environment requires reassessment. Third, responses to the primary source of stress need to be distinguished from secondary consequences of chemical damage due to failure of repair mechanisms to cope with extreme conditions. NO is generated by many mechanisms, some of which remain undefined. An example is the recent demonstration that the hybrid cluster protein combines with YtfE (or RIC protein, for repair of iron centres damaged by nitrosative stress) in a new pathway to repair key iron-sulphur proteins damaged by nitrosative stress. The functions of many genes expressed in response to nitrosative stress remain either controversial or are completely unknown. The concentration of NO that accumulates in the bacterial cytoplasm is essentially unknown, so dogmatic statements cannot be made that damage to transcription factors (Fur, FNR, SoxRS, MelR, OxyR) occurs naturally as part of a physiologically relevant signalling mechanism. Such doubts can be resolved by simple experiments to meet six proposed criteria.
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Abstract
In the course of an infection, Salmonella enterica occupies diverse anatomical sites with various concentrations of oxygen (O2) and nitric oxide (NO). These diatomic gases compete for binding to catalytic metal groups of quinol oxidases. Enterobacteriaceae express two evolutionarily distinct classes of quinol oxidases that differ in affinity for O2 and NO as well as stoichiometry of H+ translocated across the cytoplasmic membrane. The investigations presented here show that the dual function of bacterial cytochrome bd in bioenergetics and antinitrosative defense enhances Salmonella virulence. The high affinity of cytochrome bd for O2 optimizes respiratory rates in hypoxic cultures, and thus, this quinol oxidase maximizes bacterial growth under O2-limiting conditions. Our investigations also indicate that cytochrome bd, rather than cytochrome bo, is an intrinsic component of the adaptive antinitrosative toolbox of Salmonella Accordingly, induction of cytochrome bd helps Salmonella grow and respire in the presence of inhibitory NO. The combined antinitrosative defenses of cytochrome bd and the flavohemoglobin Hmp account for a great part of the adaptations that help Salmonella recover from the antimicrobial activity of NO. Moreover, the antinitrosative defenses of cytochrome bd and flavohemoglobin Hmp synergize to promote Salmonella growth in systemic tissues. Collectively, our investigations indicate that cytochrome bd is a critical means by which Salmonella resists the nitrosative stress that is engendered in the innate response of mammalian hosts while it concomitantly allows for proper O2 utilization in tissue hypoxia. IMPORTANCE It is becoming quite apparent that metabolism is critically important to the virulence potential of pathogenic microorganisms. Bacterial cells use a variety of terminal electron acceptors to power electron transport chains and metabolic processes. Of all the electron acceptors available to bacteria, utilization of O2 yields the most energy while diversifying the type of substrates that a pathogen can use. Recent investigations have demonstrated important roles for bd-type quinol oxidases with high affinity for O2 in bacterial pathogenesis. The investigations presented here have revealed that cytochrome bd potentiates virulence of a clinically relevant bacterial pathogen by fueling bioenergetics of prokaryotic cells while protecting the respiratory chain against NO toxicity. The adaptive antinitrosative defenses afforded by cytochrome bd synergize with other NO-detoxifying systems to preserve cellular bioenergetics, thereby promoting bacterial virulence in tissue hypoxia.
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6
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Regulatory Requirements for Staphylococcus aureus Nitric Oxide Resistance. J Bacteriol 2016; 198:2043-55. [PMID: 27185828 DOI: 10.1128/jb.00229-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 05/10/2016] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED The ability of Staphylococcus aureus to resist host innate immunity augments the severity and pervasiveness of its pathogenesis. Nitric oxide (NO˙) is an innate immune radical that is critical for the efficient clearance of a wide range of microbial pathogens. Exposure of microbes to NO˙ typically results in growth inhibition and induction of stress regulons. S. aureus, however, induces a metabolic state in response to NO˙ that allows for continued replication and precludes stress regulon induction. The regulatory factors mediating this distinctive response remain largely undefined. Here, we employ a targeted transposon screen and transcriptomics to identify and characterize five regulons essential for NO˙ resistance in S. aureus: three virulence regulons not formerly associated with NO˙ resistance, SarA, CodY, and Rot, as well as two regulons with established roles, Fur and SrrAB. We provide new insights into the contributions of Fur and SrrAB during NO˙ stress and show that the S. aureus ΔsarA mutant, the most sensitive of the newly identified mutants, exhibits metabolic dysfunction and widespread transcriptional dysregulation following NO˙ exposure. Altogether, our results broadly characterize the regulatory requirements for NO˙ resistance in S. aureus and suggest an intriguing overlap between the regulation of NO˙ resistance and virulence in this well-adapted human pathogen. IMPORTANCE The prolific human pathogen Staphylococcus aureus is uniquely capable of resisting the antimicrobial radical nitric oxide (NO˙), a crucial component of the innate immune response. However, a complete understanding of how S. aureus regulates an effective response to NO˙ is lacking. Here, we implicate three central virulence regulators, SarA, CodY, and Rot, as major players in the S. aureus NO˙ response. Additionally, we elaborate on the contribution of two regulators, SrrAB and Fur, already known to play a crucial role in S. aureus NO˙ resistance. Our study sheds light on a unique facet of S. aureus pathogenicity and demonstrates that the transcriptional response of S. aureus to NO˙ is highly pleiotropic and intrinsically tied to metabolism and virulence regulation.
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Vázquez-Torres A, Bäumler AJ. Nitrate, nitrite and nitric oxide reductases: from the last universal common ancestor to modern bacterial pathogens. Curr Opin Microbiol 2015; 29:1-8. [PMID: 26426528 DOI: 10.1016/j.mib.2015.09.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/01/2015] [Accepted: 09/08/2015] [Indexed: 01/16/2023]
Abstract
The electrochemical gradient that ensues from the enzymatic activity of cytochromes such as nitrate reductase, nitric oxide reductase, and quinol oxidase contributes to the bioenergetics of the bacterial cell. Reduction of nitrogen oxides by bacterial pathogens can, however, be uncoupled from proton translocation and biosynthesis of ATP or NH4(+), but still linked to quinol and NADH oxidation. Ancestral nitric oxide reductases, as well as cytochrome c oxidases and quinol bo oxidases evolved from the former, are capable of binding and detoxifying nitric oxide to nitrous oxide. The NO-metabolizing activity associated with these cytochromes can be a sizable source of antinitrosative defense in bacteria during their associations with host cells. Nitrosylation of terminal cytochromes arrests respiration, reprograms bacterial metabolism, stimulates antioxidant defenses and alters antibiotic cytotoxicity. Collectively, the bioenergetics and regulation of redox homeostasis that accompanies the utilization of nitrogen oxides and detoxification of nitric oxide by cytochromes of the electron transport chain increases fitness of many Gram-positive and -negative pathogens during their associations with invertebrate and vertebrate hosts.
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Affiliation(s)
- Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, United States; Veterans Affairs Eastern Colorado Health Care System, Denver, CO, United States.
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, University of California Davis, School of Medicine, Davis, CA, United States.
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Interplay between iron homeostasis and virulence: Fur and RyhB as major regulators of bacterial pathogenicity. Vet Microbiol 2015; 179:2-14. [PMID: 25888312 DOI: 10.1016/j.vetmic.2015.03.024] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 11/21/2022]
Abstract
In bacteria-host interactions, competition for iron is critical for the outcome of the infection. As a result of its redox properties, this metal is essential for the growth and proliferation of most living organisms, including pathogenic bacteria. This metal is also potentially toxic, making the precise maintenance of iron homeostasis necessary for survival. Iron acquisition and storage control is mediated in most bacteria by the global ferric uptake regulator (Fur) and iron-responsive small regulatory non-coding RNAs (RyhB in the model organism Escherichia coli). While the role of these regulators in iron homeostasis is well documented in both pathogenic and non-pathogenic bacteria, many recent studies also demonstrate that these regulators are involved in the virulence of pathogenic bacteria. By sensing iron availability in the environment, Fur and RyhB are able to regulate, either directly or indirectly via other transcriptional regulators or modulation of intracellular iron concentration, many virulence determinants of pathogenic bacteria. Iron is thus both a nutritional and regulatory element, allowing bacteria to adapt to various host environments by adjusting expression of virulence factors. In this review, we present evidences that Fur and RyhB are the major regulators of this adaptation, as they are involved in diverse functions ranging from iron homeostasis to regulation of virulence by mediating key pathogen responses such as invasion of eukaryotic cells, toxin production, motility, quorum sensing, stress resistance or biofilm formation. Therefore, Fur and RyhB play a major role in regulating an adaptative response during bacterial infections, making them important targets in the fight against pathogenic bacteria.
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Bogdan C. Nitric oxide synthase in innate and adaptive immunity: an update. Trends Immunol 2015; 36:161-78. [PMID: 25687683 DOI: 10.1016/j.it.2015.01.003] [Citation(s) in RCA: 558] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/14/2015] [Accepted: 01/14/2015] [Indexed: 12/22/2022]
Abstract
Thirty years after the discovery of its production by activated macrophages, our appreciation of the diverse roles of nitric oxide (NO) continues to grow. Recent findings have not only expanded our understanding of the mechanisms controlling the expression of NO synthases (NOS) in innate and adaptive immune cells, but have also revealed new functions and modes of action of NO in the control and escape of infectious pathogens, in T and B cell differentiation, and in tumor defense. I discuss these findings, in the context of a comprehensive overview of the various sources and multiple reaction partners of NO, and of the regulation of NOS2 by micromilieu factors, antisense RNAs, and 'unexpected' cytokines.
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Affiliation(s)
- Christian Bogdan
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie, und Hygiene, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Universitätsklinikum Erlangen, Wasserturmstraße 3/5, 91054 Erlangen, Germany.
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Dandekar T, Fieselmann A, Fischer E, Popp J, Hensel M, Noster J. Salmonella-how a metabolic generalist adopts an intracellular lifestyle during infection. Front Cell Infect Microbiol 2015; 4:191. [PMID: 25688337 PMCID: PMC4310325 DOI: 10.3389/fcimb.2014.00191] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/21/2014] [Indexed: 12/12/2022] Open
Abstract
The human-pathogenic bacterium Salmonella enterica adjusts and adapts to different environments while attempting colonization. In the course of infection nutrient availabilities change drastically. New techniques, "-omics" data and subsequent integration by systems biology improve our understanding of these changes. We review changes in metabolism focusing on amino acid and carbohydrate metabolism. Furthermore, the adaptation process is associated with the activation of genes of the Salmonella pathogenicity islands (SPIs). Anti-infective strategies have to take these insights into account and include metabolic and other strategies. Salmonella infections will remain a challenge for infection biology.
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Affiliation(s)
- Thomas Dandekar
- Department of Bioinformatics, Biocenter, University of Würzburg Würzburg, Germany
| | - Astrid Fieselmann
- Department of Bioinformatics, Biocenter, University of Würzburg Würzburg, Germany
| | - Eva Fischer
- Department of Bioinformatics, Biocenter, University of Würzburg Würzburg, Germany
| | - Jasmin Popp
- Division of Microbiology, Biology/Chemistry, University of Osnabrück Osnabrück, Germany
| | - Michael Hensel
- Division of Microbiology, Biology/Chemistry, University of Osnabrück Osnabrück, Germany
| | - Janina Noster
- Division of Microbiology, Biology/Chemistry, University of Osnabrück Osnabrück, Germany
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Behnsen J, Perez-Lopez A, Nuccio SP, Raffatellu M. Exploiting host immunity: the Salmonella paradigm. Trends Immunol 2015; 36:112-20. [PMID: 25582038 DOI: 10.1016/j.it.2014.12.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/12/2014] [Accepted: 12/12/2014] [Indexed: 01/08/2023]
Abstract
Pathogens have evolved clever strategies to evade and in some cases exploit the attacks of an activated immune system. Salmonella enterica is one such pathogen, exploiting multiple aspects of host defense to promote its replication in the host. Here we review recent findings on the mechanisms by which Salmonella establishes systemic and chronic infection, including strategies involving manipulation of innate immune signaling and inflammatory forms of cell death, as well as immune evasion by establishing residency in M2 macrophages. We also examine recent evidence showing that the oxidative environment and the high levels of antimicrobial proteins produced in response to localized Salmonella gastrointestinal infection enable the pathogen to successfully outcompete the resident gut microbiota.
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Affiliation(s)
- Judith Behnsen
- Department of Microbiology and Molecular Genetics, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA; Institute for Immunology, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA
| | - Araceli Perez-Lopez
- Department of Microbiology and Molecular Genetics, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA; Institute for Immunology, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA
| | - Sean-Paul Nuccio
- Department of Microbiology and Molecular Genetics, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA
| | - Manuela Raffatellu
- Department of Microbiology and Molecular Genetics, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA; Institute for Immunology, University of California, Irvine School of Medicine, Irvine, CA 92697-4025, USA.
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12
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Calderón PF, Morales EH, Acuña LG, Fuentes DN, Gil F, Porwollik S, McClelland M, Saavedra CP, Calderón IL. The small RNA RyhB homologs from Salmonella typhimurium participate in the response to S-nitrosoglutathione-induced stress. Biochem Biophys Res Commun 2014; 450:641-5. [PMID: 24937451 DOI: 10.1016/j.bbrc.2014.06.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Accepted: 06/06/2014] [Indexed: 12/25/2022]
Abstract
Typically, the expression of sRNAs is activated in response to environmental stimuli in order to regulate gene expression through post-transcriptional mechanisms. In the present work we show that the Salmonellatyphimurium paralogous sRNAs RyhB-1 and RyhB-2 are induced in response to the nitrosating agent S-nitrosoglutathione (GSNO). Inactivation of these sRNAs decreased S. typhimurium resistance to GSNO and increased the levels of nitrosylated proteins. These results prompted us to evaluate a possible role of these sRNAs in nitrosative stress resistance. RNA profiling was used as a screen to identify novel RyhB-1 and RyhB-2 regulated targets. A subset of genes was filtered based on their potential role in the response to nitrosative stress and their expression was analyzed by quantitative RT-PCR in wild type, single and double mutant strains (ΔryhB1, ΔryhB2 and ΔryhB1 ΔryhB2) treated with GSNO. In response to GSNO RyhB-1 and RyhB-2 negatively regulate the expression of the genes cyoABC (cytochrome bo oxidase), cydB (cytochrome bd oxidase), cybC (cytochrome b-562), and positively regulate the nirBCD operon (nitrite reductase system). Together, these results suggest that RyhB-1 and RyhB-2 finely tune the expression of genes coding for cytochrome oxidases and the nitrate reductase system, allowing the cell to cope with GSNO-induced stress.
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Affiliation(s)
- Paulina F Calderón
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile.
| | - Eduardo H Morales
- Great Lakes Bioenergy Research Center and Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
| | - Lillian G Acuña
- Laboratorio de Ecofisiología Microbiana, Fundación Ciencia & Vida, Santiago, Chile.
| | - Danitza N Fuentes
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile.
| | - Fernando Gil
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile.
| | - S Porwollik
- Department of Microbiology and Molecular Genetics, B240 Medical Sciences Building, University of California, Irvine, CA 92697, USA.
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, B240 Medical Sciences Building, University of California, Irvine, CA 92697, USA.
| | - Claudia P Saavedra
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile.
| | - Iván L Calderón
- Laboratorio de Microbiología Molecular, Facultad de Ciencias Biológicas, Universidad Andres Bello, Santiago, Chile.
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The iron-sensing fur regulator controls expression timing and levels of salmonella pathogenicity island 2 genes in the course of environmental acidification. Infect Immun 2014; 82:2203-10. [PMID: 24643535 DOI: 10.1128/iai.01625-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In order to survive inside macrophages, Salmonella produces a series of proteins encoded by genes within Salmonella pathogenicity island 2 (SPI-2). In the present study, we report that Fur, a central regulator of iron utilization, negatively controls the expression of SPI-2 genes. Time course analysis of SPI-2 expression after the entry of Salmonella into macrophages revealed that SPI-2 genes are induced earlier and at higher levels in the absence of the Fur regulator. It was hypothesized that Fur repressed the SPI-2 expression that was activated during acidification of the phagosome. Indeed, as pH was lowered from pH 7.0 to pH 5.5, the lack of Fur enabled SPI-2 gene expression to be induced at higher pH and to be expressed at higher levels. Fur controlled SPI-2 genes via repression of the SsrB response regulator, a primary activator of SPI-2 expression. Fur repressed ssrB expression both inside macrophages and under acidic conditions, which we ascribe to the direct binding of Fur to the ssrB promoter. Our study suggests that Salmonella could employ iron inside the phagosome to precisely control the timing and levels of SPI-2 expression inside macrophages.
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14
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Dauros-Singorenko P, Swift S. The transition from iron starvation to iron sufficiency as an important step in the progression of infection. Sci Prog 2014; 97:371-82. [PMID: 25638949 PMCID: PMC10365408 DOI: 10.3184/003685014x14151846374739] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Iron is an essential micronutrient for microbial life. At the start of an infection the host environment will normally restrict available iron, and innate immune responses will aim to further reduce iron, thus inhibiting growth of potential pathogens. Successful pathogens have developed a variety of mechanisms to acquire iron from the available in vivo sources, using remote and direct capture, to render their environment iron replete. Iron restriction, and the presence of host iron sources like haem, are important drivers of gene regulation controlling the expression of numerous virulence factors. As an infection progresses the changing iron environment will therefore influence pathogen gene expression and trigger new activities. Understanding how bacteria acquire iron, and how iron acquisition affects the bacteria, has identified vaccine and antibiotic drug targets and is now suggesting novel approaches to control and treat infection.
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Affiliation(s)
| | - Simon Swift
- Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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