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Sweet MJ, Ramnath D, Singhal A, Kapetanovic R. Inducible antibacterial responses in macrophages. Nat Rev Immunol 2024:10.1038/s41577-024-01080-y. [PMID: 39294278 DOI: 10.1038/s41577-024-01080-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2024] [Indexed: 09/20/2024]
Abstract
Macrophages destroy bacteria and other microorganisms through phagocytosis-coupled antimicrobial responses, such as the generation of reactive oxygen species and the delivery of hydrolytic enzymes from lysosomes to the phagosome. However, many intracellular bacteria subvert these responses, escaping to other cellular compartments to survive and/or replicate. Such bacterial subversion strategies are countered by a range of additional direct antibacterial responses that are switched on by pattern-recognition receptors and/or host-derived cytokines and other factors, often through inducible gene expression and/or metabolic reprogramming. Our understanding of these inducible antibacterial defence strategies in macrophages is rapidly evolving. In this Review, we provide an overview of the broad repertoire of antibacterial responses that can be engaged in macrophages, including LC3-associated phagocytosis, metabolic reprogramming and antimicrobial metabolites, lipid droplets, guanylate-binding proteins, antimicrobial peptides, metal ion toxicity, nutrient depletion, autophagy and nitric oxide production. We also highlight key inducers, signalling pathways and transcription factors involved in driving these different antibacterial responses. Finally, we discuss how a detailed understanding of the molecular mechanisms of antibacterial responses in macrophages might be exploited for developing host-directed therapies to combat antibiotic-resistant bacterial infections.
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Affiliation(s)
- Matthew J Sweet
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
| | - Divya Ramnath
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia
| | - Amit Singhal
- Infectious Diseases Labs (ID Labs), Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
| | - Ronan Kapetanovic
- INRAE, Université de Tours, Infectiologie et Santé Publique (ISP), Nouzilly, France
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2
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Larkin AA, Hagstrom GI, Brock ML, Garcia NS, Martiny AC. Basin-scale biogeography of Prochlorococcus and SAR11 ecotype replication. THE ISME JOURNAL 2023; 17:185-194. [PMID: 36273241 PMCID: PMC9589681 DOI: 10.1038/s41396-022-01332-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022]
Abstract
Establishing links between microbial diversity and environmental processes requires resolving the high degree of functional variation among closely related lineages or ecotypes. Here, we implement and validate an improved metagenomic approach that estimates the spatial biogeography and environmental regulation of ecotype-specific replication patterns (RObs) across ocean regions. A total of 719 metagenomes were analyzed from meridional Bio-GO-SHIP sections in the Atlantic and Indian Ocean. Accounting for sequencing bias and anchoring replication estimates in genome structure were critical for identifying physiologically relevant biological signals. For example, ecotypes within the dominant marine cyanobacteria Prochlorococcus exhibited distinct diel cycles in RObs that peaked between 19:00-22:00. Additionally, both Prochlorococcus ecotypes and ecotypes within the highly abundant heterotroph Pelagibacter (SAR11) demonstrated systematic biogeographies in RObs that differed from spatial patterns in relative abundance. Finally, RObs was significantly regulated by nutrient stress and temperature, and explained by differences in the genomic potential for nutrient transport, energy production, cell wall structure, and replication. Our results suggest that our new approach to estimating replication is reflective of gross population growth. Moreover, this work reveals that the interaction between adaptation and environmental change drives systematic variability in replication patterns across ocean basins that is ecotype-specific, adding an activity-based dimension to our understanding of microbial niche space.
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Affiliation(s)
- Alyse A Larkin
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - George I Hagstrom
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | - Melissa L Brock
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA
| | - Nathan S Garcia
- Department of Earth System Science, University of California, Irvine, CA, USA
| | - Adam C Martiny
- Department of Earth System Science, University of California, Irvine, CA, USA.
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA, USA.
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3
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Defenses of multidrug resistant pathogens against reactive nitrogen species produced in infected hosts. Adv Microb Physiol 2022; 80:85-155. [PMID: 35489794 DOI: 10.1016/bs.ampbs.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacterial pathogens have sophisticated systems that allow them to survive in hosts in which innate immunity is the frontline of defense. One of the substances produced by infected hosts is nitric oxide (NO) that together with its derived species leads to the so-called nitrosative stress, which has antimicrobial properties. In this review, we summarize the current knowledge on targets and protective systems that bacteria have to survive host-generated nitrosative stress. We focus on bacterial pathogens that pose serious health concerns due to the growing increase in resistance to currently available antimicrobials. We describe the role of nitrosative stress as a weapon for pathogen eradication, the detoxification enzymes, protein/DNA repair systems and metabolic strategies that contribute to limiting NO damage and ultimately allow survival of the pathogen in the host. Additionally, this systematization highlights the lack of available data for some of the most important human pathogens, a gap that urgently needs to be addressed.
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4
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Shalaby MA, Anwar MM, Saeed H. Nanomaterials for application in wound Healing: current state-of-the-art and future perspectives. JOURNAL OF POLYMER RESEARCH 2022. [DOI: 10.1007/s10965-021-02870-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AbstractNanoparticles are the gateway to the new era in drug delivery of biocompatible agents. Several products have emerged from nanomaterials in quest of developing practical wound healing dressings that are nonantigenic, antishear stress, and gas-exchange permeable. Numerous studies have isolated and characterised various wound healing nanomaterials and nanoproducts. The electrospinning of natural and synthetic materials produces fine products that can be mixed with other wound healing medications and herbs. Various produced nanomaterials are highly influential in wound healing experimental models and can be used commercially as well. This article reviewed the current state-of-the-art and briefly specified the future concerns regarding the different systems of nanomaterials in wound healing (i.e., inorganic nanomaterials, organic and hybrid nanomaterials, and nanofibers). This review may be a comprehensive guidance to help health care professionals identify the proper wound healing materials to avoid the usual wound complications.
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5
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Crane JK, Burke SR, Alvarado CL. Inhibition of SOS Response by Nitric Oxide Donors in Escherichia coli Blocks Toxin Production and Hypermutation. Front Cell Infect Microbiol 2022; 11:798136. [PMID: 35004358 PMCID: PMC8727911 DOI: 10.3389/fcimb.2021.798136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/30/2021] [Indexed: 12/03/2022] Open
Abstract
Background Previous reports have differed as to whether nitric oxide inhibits or stimulates the SOS response, a bacterial stress response that is often triggered by DNA damage. The SOS response is an important regulator of production of Shiga toxins (Stx) in Shiga-toxigenic E. coli (STEC). In addition, the SOS response is accompanied by hypermutation, which can lead to de novo emergence of antibiotic resistance. We studied these effects in vitro as well as in vivo. Results Nitric oxide donors inhibited induction of the SOS response by classical inducers such as mitomycin C, ciprofloxacin, and zidovudine, as measured by assays for E. coli RecA. Nitric oxide donors also inhibited Stx toxin protein production as well as stx2 RNA in vitro and in vivo. In vivo experiments were performed with ligated ileal segments in the rabbit using a 20 h infection. The NO donor S-nitroso-acetylpenicillamine (SNAP) reduced hypermutation in vitro and in vivo, as measured by emergence of rifampin resistance. SNAP blocked the ability of the RecA protein to bind to single-stranded DNA in an electrophoretic mobility shift assay (EMSA) in vitro, an early event in the SOS response. The inhibitory effects of SNAP were additive with those of zinc acetate. Conclusions Nitric oxide donors blocked the initiation step of the SOS response. Downstream effects of this blockade included inhibition of Stx production and of hypermutation. Infection of rabbit loops with STEC resulted in a downregulation, rather than stimulation, of nitric oxide host defenses at 20 h of infection.
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Affiliation(s)
- John K Crane
- Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Sarah R Burke
- Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
| | - Cassandra L Alvarado
- Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, United States
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6
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Guo K, Gao H. Physiological Roles of Nitrite and Nitric Oxide in Bacteria: Similar Consequences from Distinct Cell Targets, Protection, and Sensing Systems. Adv Biol (Weinh) 2021; 5:e2100773. [PMID: 34310085 DOI: 10.1002/adbi.202100773] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/19/2021] [Indexed: 12/22/2022]
Abstract
Nitrite and nitric oxide (NO) are two active nitrogen oxides that display similar biochemical properties, especially when interacting with redox-sensitive proteins (i.e., hemoproteins), an observation serving as the foundation of the notion that the antibacterial effect of nitrite is largely attributed to NO formation. However, a growing body of evidence suggests that they are largely treated as distinct molecules by bacterial cells. Although both nitrite and NO are formed and decomposed by enzymes participating in the transformation of these nitrogen species, NO can also be generated via amino acid metabolism by bacterial NO synthetase and scavenged by flavohemoglobin. NO seemingly interacts with all hemoproteins indiscriminately, whereas nitrite shows high specificity to heme-copper oxidases. Consequently, the homeostasis of redox-sensitive proteins may be responsible for the substantial difference in NO-targets identified to date among different bacteria. In addition, most protective systems against NO damage have no significant role in alleviating inhibitory effects of nitrite. Furthermore, when functioning as signal molecules, nitrite and NO are perceived by completely different sensing systems, through which they are linked to different biological processes.
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Affiliation(s)
- Kailun Guo
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
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7
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Porrini C, Ramarao N, Tran SL. Dr. NO and Mr. Toxic - the versatile role of nitric oxide. Biol Chem 2021; 401:547-572. [PMID: 31811798 DOI: 10.1515/hsz-2019-0368] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/04/2019] [Indexed: 12/25/2022]
Abstract
Nitric oxide (NO) is present in various organisms from humans, to plants, fungus and bacteria. NO is a fundamental signaling molecule implicated in major cellular functions. The role of NO ranges from an essential molecule to a potent mediator of cellular damages. The ability of NO to react with a broad range of biomolecules allows on one hand its regulation and a gradient concentration and on the other hand to exert physiological as well as pathological functions. In humans, NO is implicated in cardiovascular homeostasis, neurotransmission and immunity. However, NO can also contribute to cardiovascular diseases (CVDs) or septic shock. For certain denitrifying bacteria, NO is part of their metabolism as a required intermediate of the nitrogen cycle. However, for other bacteria, NO is toxic and harmful. To survive, those bacteria have developed processes to resist this toxic effect and persist inside their host. NO also contributes to maintain the host/microbiota homeostasis. But little is known about the impact of NO produced during prolonged inflammation on microbiota integrity, and some pathogenic bacteria take advantage of the NO response to colonize the gut over the microbiota. Taken together, depending on the environmental context (prolonged production, gradient concentration, presence of partners for interaction, presence of oxygen, etc.), NO will exert its beneficial or detrimental function. In this review, we highlight the dual role of NO for humans, pathogenic bacteria and microbiota, and the mechanisms used by each organism to produce, use or resist NO.
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Affiliation(s)
- Constance Porrini
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Nalini Ramarao
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Seav-Ly Tran
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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8
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Antimicrobial nanomedicine for ocular bacterial and fungal infection. Drug Deliv Transl Res 2021; 11:1352-1375. [PMID: 33840082 DOI: 10.1007/s13346-021-00966-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2021] [Indexed: 12/13/2022]
Abstract
Ocular infection induced by bacteria and fungi is a major cause of visual impairment and blindness. Topical administration of antibiotics remains the first-line treatment, as effective eradication of pathogens is the core of the anti-infection strategy. Whereas, eye drops lack efficiency and have relatively low bioavailability. Intraocular injection may cause concurrent ocular damage and secondary infection. In addition, antibiotic-based management can be limited by the low sensitivity to multidrug-resistant bacteria. Nanomedicine is proposed as a prospective, effective, and noninvasive platform to mediate ocular delivery and combat pathogen or even resistant strains. Nanomedicine can not only carry antimicrobial agents to fight against pathogens but also directly active microbicidal capability, killing pathogens. More importantly, by modification, nanomedicine can achieve enhanced residence time and release time on the cornea, and easy penetration through corneal tissues into anterior and posterior segments of the eye, thus improving the therapeutic effect for ocular infection. In this review, several categories of antimicrobial nanomedicine are systematically discussed, where the efficiency and possibility of further embellishment and improvement to adapt to clinical use are also investigated. All in all, novel antimicrobial nanomedicine provides potent and prospective ways to manage severe and refractory ocular infections.
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9
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Al-Shehri SS. Reactive oxygen and nitrogen species and innate immune response. Biochimie 2020; 181:52-64. [PMID: 33278558 DOI: 10.1016/j.biochi.2020.11.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 11/21/2020] [Accepted: 11/30/2020] [Indexed: 12/30/2022]
Abstract
The innate immune system is the first line of defense against pathogens and is characterized by its fast but nonspecific response. One important mechanism of this system is the production of the biocidal reactive oxygen and nitrogen species, which are widely distributed within biological systems, including phagocytes and secretions. Reactive oxygen and nitrogen species are short-lived intermediates that are biochemically synthesized by various enzymatic reactions in aerobic organisms and are regulated by antioxidants. The physiological levels of reactive species play important roles in cellular signaling and proliferation. However, higher concentrations and prolonged exposure can fight infections by damaging important microbial biomolecules. One feature of the reactive species generation system is the interaction between its components to produce more biocidal agents. For example, the phagocytic NADPH oxidase complex generates superoxide, which functions as a precursor for antimicrobial hydrogen peroxide synthesis. Peroxide is then used by myeloperoxidase in the same cells to generate hypochlorous acid, a highly microbicidal agent. Studies on animal models and microorganisms have shown that deficiency of these antimicrobial agents is associated with severe recurrent infections and immunocompromised diseases, such as chronic granulomatous disease. There is accumulating evidence that reactive species have important positive aspects on human health and immunity; however, some important promising features of this system remain obscure.
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Affiliation(s)
- Saad S Al-Shehri
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P. O. Box 11099, Taif, 21944, Saudi Arabia.
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10
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Abstract
We have previously shown that the host-derived antimicrobial mediator nitric oxide (NO·) mobilizes zinc from bacterial metalloproteins. The present study demonstrates that NO· inactivates the essential iron-containing enzyme peptide deformylase, both by promoting its mismetallation by zinc and by directly modifying its metal-binding site. We explain how free intracellular zinc is detrimental for cells and reveal a new mechanism of NO·-mediated bacterial growth inhibition that is distinct from previously known targets. Salmonella enterica serovar Typhimurium is an intracellular pathogen that elicits nitric oxide (NO·) production by host macrophages. NO· is a potent antimicrobial mediator with diverse targets, including protein thiols and metal centers. The mobilization of zinc from metalloproteins by NO· increases the availability of free intracellular zinc, which is detrimental to bacterial cells, but the precise mechanism of zinc cytotoxicity is uncertain. Here, we show that excess zinc results in the mismetallation of the essential iron-containing enzyme peptide deformylase (PDF), thereby diminishing its activity. PDF mismetallation is observed in zinc-treated bacteria lacking the zinc exporters ZntA and ZitB and is also observed during nitrosative stress, suggesting that NO·-mediated zinc mobilization results in PDF mismetallation. However, NO· also inhibits PDF directly by S-nitrosylating the metal-binding Cys90 residue. These observations identify PDF as an essential bacterial protein that is subject to both direct and indirect inactivation by NO·, providing a novel mechanism of zinc toxicity and NO·-mediated antibacterial activity.
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11
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Yousuf S, Karlinsey JE, Neville SL, McDevitt CA, Libby SJ, Fang FC, Frawley ER. Manganese import protects Salmonella enterica serovar Typhimurium against nitrosative stress. Metallomics 2020; 12:1791-1801. [PMID: 33078811 DOI: 10.1039/d0mt00178c] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Nitric oxide (NO˙) is a radical molecule produced by mammalian phagocytic cells as part of the innate immune response to bacterial pathogens. It exerts its antimicrobial activity in part by impairing the function of metalloproteins, particularly those containing iron and zinc cofactors. The pathogenic Gram-negative bacterium Salmonella enterica serovar typhimurium undergoes dynamic changes in its cellular content of the four most common metal cofactors following exposure to NO˙ stress. Zinc, iron and magnesium all decrease in response to NO˙ while cellular manganese increases significantly. Manganese acquisition is driven primarily by increased expression of the mntH and sitABCD transporters following derepression of MntR and Fur. ZupT also contributes to manganese acquisition in response to nitrosative stress. S. Typhimurium mutants lacking manganese importers are more sensitive to NO˙, indicating that manganese is important for resistance to nitrosative stress.
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Affiliation(s)
- Shehla Yousuf
- Rhodes College Biology Department, 2000 North Parkway, Memphis, TN 38112, USA.
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12
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von Pein JB, Stocks CJ, Schembri MA, Kapetanovic R, Sweet MJ. An alloy of zinc and innate immunity: Galvanising host defence against infection. Cell Microbiol 2020; 23:e13268. [PMID: 32975847 DOI: 10.1111/cmi.13268] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 12/16/2022]
Abstract
Innate immune cells such as macrophages and neutrophils initiate protective inflammatory responses and engage antimicrobial responses to provide frontline defence against invading pathogens. These cells can both restrict the availability of certain transition metals that are essential for microbial growth and direct toxic concentrations of metals towards pathogens as antimicrobial responses. Zinc is important for the structure and function of many proteins, however excess zinc can be cytotoxic. In recent years, several studies have revealed that innate immune cells can deliver toxic concentrations of zinc to intracellular pathogens. In this review, we discuss the importance of zinc status during infectious disease and the evidence for zinc intoxication as an innate immune antimicrobial response. Evidence for pathogen subversion of this response is also examined. The likely mechanisms, including the involvement of specific zinc transporters that facilitate delivery of zinc by innate immune cells for metal ion poisoning of pathogens are also considered. Precise mechanisms by which excess levels of zinc can be toxic to microorganisms are then discussed, particularly in the context of synergy with other antimicrobial responses. Finally, we highlight key unanswered questions in this emerging field, which may offer new opportunities for exploiting innate immune responses for anti-infective development.
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Affiliation(s)
- Jessica B von Pein
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Claudia J Stocks
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Mark A Schembri
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
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13
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Yu T, Jiang G, Gao R, Chen G, Ren Y, Liu J, van der Mei HC, Busscher HJ. Circumventing antimicrobial-resistance and preventing its development in novel, bacterial infection-control strategies. Expert Opin Drug Deliv 2020; 17:1151-1164. [PMID: 32510243 DOI: 10.1080/17425247.2020.1779697] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Development of new antimicrobials with ever 'better' bacterial killing has long been considered the appropriate response to the growing threat of antimicrobial-resistant infections. However, the time-period between the introduction of a new antibiotic and the appearance of resistance amongst bacterial pathogens is getting shorter and shorter. This suggests that alternative pathways than making ever 'better' antimicrobials should be taken. AREAS COVERED This review aims to answer the questions (1) whether we have means to circumvent existing antibiotic-resistance mechanisms, (2) whether we can revert existing antibiotic-resistance, (3) how we can prevent the development of antimicrobial-resistance against novel infection-control strategies, including nano-antimicrobials. EXPERT OPINION Relying on relieving antibiotic-pressure and natural outcompeting of antimicrobial-resistant bacteria seems an uncertain way out of the antibiotic-crisis facing us. Novel, non-antibiotic, nanotechnology-based infection control-strategies are promising. At the same time, rapid development of new resistance mechanisms once novel strategies is taken into global clinical use, may not be ruled out and must be closely monitored. This suggests focusing research and development on designing suitable combinations of existing antibiotics with new nano-antimicrobials in a way that induction of new antimicrobial-resistance mechanisms is avoided. The latter suggestion, however, requires a change of focus in research and development.
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Affiliation(s)
- Tianrong Yu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Jiangsu, P. R. China.,Department of Biomedical Engineering, University of Groningen and University Medical Center , Groningen, The Netherlands
| | - Guimei Jiang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Jiangsu, P. R. China.,Department of Biomedical Engineering, University of Groningen and University Medical Center , Groningen, The Netherlands
| | - Ruifang Gao
- Department of Biomedical Engineering, University of Groningen and University Medical Center , Groningen, The Netherlands.,College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou, P.R. China
| | - Gaojian Chen
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University , Suzhou, P.R. China
| | - Yijin Ren
- Department of Orthodontics, University of Groningen and University Medical Center of Groningen , Groningen, The Netherlands
| | - Jian Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Jiangsu, P. R. China
| | - Henny C van der Mei
- Department of Biomedical Engineering, University of Groningen and University Medical Center , Groningen, The Netherlands
| | - Henk J Busscher
- Department of Biomedical Engineering, University of Groningen and University Medical Center , Groningen, The Netherlands
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14
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Stocks CJ, von Pein JB, Curson JEB, Rae J, Phan MD, Foo D, Bokil NJ, Kambe T, Peters KM, Parton RG, Schembri MA, Kapetanovic R, Sweet MJ. Frontline Science: LPS-inducible SLC30A1 drives human macrophage-mediated zinc toxicity against intracellular Escherichia coli. J Leukoc Biol 2020; 109:287-297. [PMID: 32441444 PMCID: PMC7891337 DOI: 10.1002/jlb.2hi0420-160r] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/22/2020] [Accepted: 04/28/2020] [Indexed: 12/12/2022] Open
Abstract
TLR-inducible zinc toxicity is an antimicrobial mechanism utilized by macrophages, however knowledge of molecular mechanisms mediating this response is limited. Here, we show that E. coli exposed to zinc stress within primary human macrophages reside in membrane-bound vesicular compartments. Since SLC30A zinc exporters can deliver zinc into the lumen of vesicles, we examined LPS-regulated mRNA expression of Slc30a/SLC30A family members in primary mouse and human macrophages. A number of these transporters were dynamically regulated in both cell populations. In human monocyte-derived macrophages, LPS strongly up-regulated SLC30A1 mRNA and protein expression. In contrast, SLC30A1 was not LPS-inducible in macrophage-like PMA-differentiated THP-1 cells. We therefore ectopically expressed SLC30A1 in these cells, finding that this was sufficient to promote zinc-containing vesicle formation. The response was similar to that observed following LPS stimulation. Ectopically expressed SLC30A1 localized to both the plasma membrane and intracellular zinc-containing vesicles within LPS-stimulated THP-1 cells. Inducible overexpression of SLC30A1 in THP-1 cells infected with the Escherichia coli K-12 strain MG1655 augmented the zinc stress response of intracellular bacteria and promoted clearance. Furthermore, in THP-1 cells infected with an MG1655 zinc stress reporter strain, all bacteria contained within SLC30A1-positive compartments were subjected to zinc stress. Thus, SLC30A1 marks zinc-containing compartments associated with TLR-inducible zinc toxicity in human macrophages, and its ectopic over-expression is sufficient to initiate this antimicrobial pathway in these cells. Finally, SLC30A1 silencing did not compromise E. coli clearance by primary human macrophages, suggesting that other zinc exporters may also contribute to the zinc toxicity response.
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Affiliation(s)
- Claudia J Stocks
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Jessica B von Pein
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - James E B Curson
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - James Rae
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia
| | - Minh-Duy Phan
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Darren Foo
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Nilesh J Bokil
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kate M Peters
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland, Australia
| | - Mark A Schembri
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia.,School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, St. Lucia, Queensland, Australia.,IMB Centre for Inflammation and Disease Research, The University of Queensland, St. Lucia, Queensland, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland, Australia
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15
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Sinha AK, Possoz C, Leach DRF. The Roles of Bacterial DNA Double-Strand Break Repair Proteins in Chromosomal DNA Replication. FEMS Microbiol Rev 2020; 44:351-368. [PMID: 32286623 PMCID: PMC7326373 DOI: 10.1093/femsre/fuaa009] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/09/2020] [Indexed: 02/06/2023] Open
Abstract
It is well established that DNA double-strand break (DSB) repair is required to underpin chromosomal DNA replication. Because DNA replication forks are prone to breakage, faithful DSB repair and correct replication fork restart are critically important. Cells, where the proteins required for DSB repair are absent or altered, display characteristic disturbances to genome replication. In this review, we analyze how bacterial DNA replication is perturbed in DSB repair mutant strains and explore the consequences of these perturbations for bacterial chromosome segregation and cell viability. Importantly, we look at how DNA replication and DSB repair processes are implicated in the striking recent observations of DNA amplification and DNA loss in the chromosome terminus of various mutant Escherichia coli strains. We also address the mutant conditions required for the remarkable ability to copy the entire E. coli genome, and to maintain cell viability, even in the absence of replication initiation from oriC, the unique origin of DNA replication in wild type cells. Furthermore, we discuss the models that have been proposed to explain these phenomena and assess how these models fit with the observed data, provide new insights and enhance our understanding of chromosomal replication and termination in bacteria.
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Affiliation(s)
- Anurag Kumar Sinha
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen, 2200, Denmark
| | - Christophe Possoz
- Evolution and maintenance of circular chromosomes, Genome biology department, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, 1 avenue de la Terrasse Building 26, 91198 Gif-sur-Yvette, France
| | - David R F Leach
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh, EH9 3FF, United Kingdom
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16
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Jones-Carson J, Yahashiri A, Kim JS, Liu L, Fitzsimmons LF, Weiss DS, Vázquez-Torres A. Nitric oxide disrupts bacterial cytokinesis by poisoning purine metabolism. SCIENCE ADVANCES 2020; 6:eaaz0260. [PMID: 32133408 PMCID: PMC7043908 DOI: 10.1126/sciadv.aaz0260] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/04/2019] [Indexed: 06/02/2023]
Abstract
Cytostasis is the most salient manifestation of the potent antimicrobial activity of nitric oxide (NO), yet the mechanism by which NO disrupts bacterial cell division is unknown. Here, we show that in respiring Escherichia coli, Salmonella, and Bacillus subtilis, NO arrests the first step in division, namely, the GTP-dependent assembly of the bacterial tubulin homolog FtsZ into a cytokinetic ring. FtsZ assembly fails in respiring cells because NO inactivates inosine 5'-monophosphate dehydrogenase in de novo purine nucleotide biosynthesis and quinol oxidases in the electron transport chain, leading to drastic depletion of nucleoside triphosphates, including the GTP needed for the polymerization of FtsZ. Despite inhibiting respiration and dissipating proton motive force, NO does not destroy Z ring formation and only modestly decreases nucleoside triphosphates in glycolytic cells, which obtain much of their ATP by substrate-level phosphorylation and overexpress inosine 5'-monophosphate dehydrogenase. Purine metabolism dictates the susceptibility of early morphogenic steps in cytokinesis to NO toxicity.
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Affiliation(s)
- Jessica Jones-Carson
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
- Division of Infectious Diseases, University of Colorado School of Medicine, Aurora, CO, USA
| | - Atsushi Yahashiri
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, IA, USA
| | - Ju-Sim Kim
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lin Liu
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Liam F. Fitzsimmons
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - David S. Weiss
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, IA, USA
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
- Veterans Administration Eastern Colorado Health Care System, Aurora, CO, USA
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17
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Abstract
Staphylococcus aureus has the ability to cause infections in a variety of niches, suggesting a robust metabolic capacity facilitating proliferation under various nutrient conditions. The mature skin abscess is glucose depleted, indicating that peptides and free amino acids are important sources of nutrients for S. aureus. Our studies have found that mutations in both pyruvate carboxykinase and glutamate dehydrogenase, enzymes that function in essential gluconeogenesis reactions when amino acids serve as the major carbon source, reduce bacterial burden in a murine skin abscess model. Moreover, peptides liberated from collagen by host protease MMP-9 as well as the staphylococcal protease aureolysin support S. aureus growth in an Opp3-dependent manner under nutrient-limited conditions. Additionally, the presence of peptides induces aureolysin expression. Overall, these studies define one pathway by which S. aureus senses a nutrient-limiting environment and induces factors that function to acquire and utilize carbon from host-derived sources. Staphylococcus aureus has the ability to cause infections in multiple organ systems, suggesting an ability to rapidly adapt to changing carbon and nitrogen sources. Although there is little information about the nutrients available at specific sites of infection, a mature skin abscess has been characterized as glucose depleted, indicating that peptides and free amino acids are an important source of nutrients for the bacteria. Our studies have found that mutations in enzymes necessary for growth on amino acids, including pyruvate carboxykinase (ΔpckA) and glutamate dehydrogenase (ΔgudB), reduced the ability of the bacteria to proliferate within a skin abscess, suggesting that peptides and free amino acids are important for S. aureus growth. Furthermore, we found that collagen, an abundant host protein that is present throughout a skin abscess, serves as a reservoir of peptides. To liberate peptides from the collagen, we identified that the host protease, MMP-9, as well as the staphylococcal proteases aureolysin and staphopain B function to cleave collagen into peptide fragments that can support S. aureus growth under nutrient-limited conditions. Moreover, the oligopeptide transporter Opp3 is the primary staphylococcal transporter responsible for peptide acquisition. Lastly, we observed that the presence of peptides (3-mer to 7-mer) induces the expression of aureolysin, suggesting that S. aureus has the ability to detect peptides in the environment.
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18
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Yim B, Park JH, Jeong H, Hong J, Kim M, Chang M, Chuck RS, Park CY. Effect of Nitric Oxide on Acanthamoeba castellanii. Invest Ophthalmol Vis Sci 2019; 59:3239-3248. [PMID: 29971441 DOI: 10.1167/iovs.18-23786] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Acanthamoeba keratitis is a well-known intractable corneal infectious disease. We investigated the anti-Acanthamoeba effect of exogenous nitric oxide (NO). Methods Acanthamoeba castellanii was axenically cultured and exposed to various concentrations of NO donors, such as sodium nitrite, sodium nitroprusside (SNP), and NO-releasing silica nanoparticles (coated in branched polyethylene imine, size:100 nm), for 1 to 7 days (sodium nitrite and SNP: 0, 0.1, 1, 10, 100, and 1000 μM; silica nanoparticles: 0, 6.25, 12.5, 25, 50, and 100 μg/mL). Human corneal epithelial cells (HCECs) were cultured and exposed to sodium nitrite, SNP (0, 0.1, 1, 10, 100, and 1000 μM), and silica nanoparticles for 1, 2, and 3 days. Results Sodium nitrite and SNP showed a dose-dependent inhibitory effect on A. castellanii viability. A more prominent inhibitory effect was observed with SNP (less than 10% of organisms survived at 7-day culture with 1000 μM) compared with sodium nitrite. However, more cytotoxicity on HCEC was observed with SNP. NO-releasing silica nanoparticles were successfully internalized into the amoebic cytoplasm and accumulated in large vacuoles. Although blank silica nanoparticles had no inhibitory effect on A. castellanii viability, NO-releasing silica nanoparticles showed a dose-dependent amoebicidal effect. Furthermore, no cystic transformation of A. castellanii was observed under a phase contrast microscope or transmission electron microscope after exogenous NO treatment. Conclusions Our results demonstrated the anti-Acanthamoeba effect of exogenous NO. This finding suggests that NO-releasing drug platforms, including nano-carriers, can be a promising therapeutic strategy for Acanthamoeba keratitis.
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Affiliation(s)
- Bora Yim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Joo-Hee Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Hyejoong Jeong
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, South Korea
| | - Jinkee Hong
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, South Korea
| | - Martha Kim
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Minwook Chang
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
| | - Roy S Chuck
- Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York, United States
| | - Choul Yong Park
- Department of Ophthalmology, Dongguk University, Ilsan Hospital, Goyang, South Korea
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19
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Zinc-dependent substrate-level phosphorylation powers Salmonella growth under nitrosative stress of the innate host response. PLoS Pathog 2018; 14:e1007388. [PMID: 30365536 PMCID: PMC6221366 DOI: 10.1371/journal.ppat.1007388] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/07/2018] [Accepted: 10/07/2018] [Indexed: 12/13/2022] Open
Abstract
The metabolic processes that enable the replication of intracellular Salmonella under nitrosative stress conditions engendered in the innate response of macrophages are poorly understood. A screen of Salmonella transposon mutants identified the ABC-type high-affinity zinc uptake system ZnuABC as a critical determinant of the adaptation of Salmonella to the nitrosative stress generated by the enzymatic activity of inducible nitric oxide (NO) synthase of mononuclear phagocytic cells. NO limits the virulence of a znuB mutant in an acute murine model of salmonellosis. The ZnuABC transporter is crucial for the glycolytic function of fructose bisphosphate aldolase, thereby fueling growth of Salmonella during nitrosative stress produced in the innate response of macrophages. Our investigations demonstrate that glycolysis mediates resistance of Salmonella to the antimicrobial activity of NO produced in an acute model of infection. The ATP synthesized by substrate-level phosphorylation at the payoff phase of glycolysis and acetate fermentation powers the replication of Salmonella experiencing high levels of nitrosative stress. In contrast, despite its high potential for ATP synthesis, oxidative phosphorylation is a major target of inhibition by NO and contributes little to the antinitrosative defenses of intracellular Salmonella. Our investigations have uncovered a previously unsuspected conjunction between zinc homeostasis, glucose metabolism and cellular energetics in the adaptation of intracellular Salmonella to the reactive nitrogen species synthesized in the innate host response. Microbial pathogens are exposed to multiple antimicrobial defenses during their associations with host cells. Nitric oxide generated in the innate response exerts widespread antimicrobial activity against a variety of pathogenic microorganisms. Nitric oxide has high affinity for metal groups of terminal cytochromes of the respiratory chain, and thus nitrosative stress exerts extreme deleterious actions against the cellular energetics that rely on oxidative phosphorylation. Intracellular Salmonella have resolved this dilemma by satisfying a significant portion of their energetic demands via substrate level phosphorylation in the payoff phase of glycolysis and acetate fermentation. A high affinity zinc uptake system promotes antinitrosative defense of intracellular Salmonella by in great part supporting the enzymatic activity of an essential enzyme in the preparatory phase of glycolysis. Our research provides novel insights into the metabolic and energetic adaptations that allow a bacterial pathogen to thrive in the midst of the innate host response of vertebrate cells.
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20
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Abstract
Nitric oxide (NO·) produced by mammalian cells exerts antimicrobial actions that result primarily from the modification of protein thiols (S-nitrosylation) and metal centers. A comprehensive approach was used to identify novel targets of NO· in Salmonella enterica serovar Typhimurium (S. Typhimurium). Newly identified targets include zinc metalloproteins required for DNA replication and repair (DnaG, PriA, and TopA), protein synthesis (AlaS and RpmE), and various metabolic activities (ClpX, GloB, MetE, PepA, and QueC). The cytotoxic actions of free zinc are mitigated by the ZntA and ZitB zinc efflux transporters, which are required for S. Typhimurium resistance to zinc overload and nitrosative stress in vitro Zinc efflux also ameliorates NO·-dependent zinc mobilization following internalization by activated macrophages and is required for virulence in NO·-producing mice, demonstrating that host-derived NO· causes zinc stress in intracellular bacteria.IMPORTANCE Nitric oxide (NO·) is produced by macrophages in response to inflammatory stimuli and restricts the growth of intracellular bacteria. Mechanisms of NO·-dependent antimicrobial actions are incompletely understood. Here, we show that zinc metalloproteins are important targets of NO· in Salmonella, including the DNA replication proteins DnaG and PriA, which were hypothesized to be NO· targets in earlier studies. Like iron, zinc is a cofactor for several essential proteins but is toxic at elevated concentrations. This study demonstrates that NO· mobilizes free zinc in Salmonella and that specific efflux transporters ameliorate the cytotoxic effects of free zinc during infection.
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21
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Kim WS, Shin MK, Shin SJ. MAP1981c, a Putative Nucleic Acid-Binding Protein, Produced by Mycobacterium avium subsp. paratuberculosis, Induces Maturation of Dendritic Cells and Th1-Polarization. Front Cell Infect Microbiol 2018; 8:206. [PMID: 29977867 PMCID: PMC6021526 DOI: 10.3389/fcimb.2018.00206] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/05/2018] [Indexed: 12/23/2022] Open
Abstract
Mycobacterium avium subsp. paratuberculosis (MAP) is the causative pathogen of chronic granulomatous enteropathy (Johne's disease) in animals, and has been focused on its association with various autoimmune diseases in humans, including Crohn's disease. The discovery of novel mycobacterial antigens and exploring their role in host immunity can contribute to the advancement of effective defense strategies including vaccines and diagnostic tools. In a preliminary study, we identified cellular extract proteins of MAP that strongly react with the blood of patients with Crohn's disease. In particular, MAP1981c, a putative nucleic acid-binding protein, showed high expression levels and strong reactivity to IgG and IgM in the sera of patients. Here, we investigated the immunological features of MAP1981c and focused on its interaction with dendritic cells (DCs), confirming its immunomodulatory ability. MAP1981c was shown to recognize Toll-like receptor (TLR) 4, and induce DC maturation and activation by increasing the expression of co-stimulatory (CD80 and CD86) and MHC class I/II molecules and the secretion of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) in DCs. This DC activation by MAP1981c was mediated by downstream signaling of TLR4 via MyD88- and TRIF-, MAP kinase-, and NF-κB-dependent signaling pathways. In addition, MAP1981c-treated DCs activated naïve T cells and induced the differentiation of CD4+ and CD8+ T cells to express T-bet, IFN-γ, and/or IL-2, but not GATA-3 and IL-4, thus indicating that MAP1981c contributes to Th1-type immune responses both in vitro and in vivo. Taken together, these results suggest that MAP1981c is a novel immunocompetent antigen that induces DC maturation and a Th1-biased response upon DC activation, suggesting that MAP1981c can be an effective vaccine and diagnostic target.
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Affiliation(s)
- Woo Sik Kim
- Department of Microbiology and Institute for Immunology and Immunological Diseases, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea.,Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, South Korea
| | - Min-Kyoung Shin
- Department of Microbiology, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, South Korea
| | - Sung Jae Shin
- Department of Microbiology and Institute for Immunology and Immunological Diseases, Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
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22
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Abstract
In all organisms, replication impairments are an important source of genome rearrangements, mainly because of the formation of double-stranded DNA (dsDNA) ends at inactivated replication forks. Three reactions for the formation of dsDNA ends at replication forks were originally described for Escherichia coli and became seminal models for all organisms: the encounter of replication forks with preexisting single-stranded DNA (ssDNA) interruptions, replication fork reversal, and head-to-tail collisions of successive replication rounds. Here, we first review the experimental evidence that now allows us to know when, where, and how these three different reactions occur in E. coli. Next, we recall our recent studies showing that in wild-type E. coli, spontaneous replication fork breakage occurs in 18% of cells at each generation. We propose that it results from the replication of preexisting nicks or gaps, since it does not involve replication fork reversal or head-to-tail fork collisions. In the recB mutant, deficient for double-strand break (DSB) repair, fork breakage triggers DSBs in the chromosome terminus during cell division, a reaction that is heritable for several generations. Finally, we recapitulate several observations suggesting that restart from intact inactivated replication forks and restart from recombination intermediates require different sets of enzymatic activities. The finding that 18% of cells suffer replication fork breakage suggests that DNA remains intact at most inactivated forks. Similarly, only 18% of cells need the helicase loader for replication restart, which leads us to speculate that the replicative helicase remains on DNA at intact inactivated replication forks and is reactivated by the replication restart proteins.
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23
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Zhai D, Ye Z, Jiang Y, Xu C, Ruan B, Yang Y, Lei X, Xiang A, Lu H, Zhu Z, Yan Z, Wei D, Li Q, Wang L, Lu Z. MOTS-c peptide increases survival and decreases bacterial load in mice infected with MRSA. Mol Immunol 2017; 92:151-160. [DOI: 10.1016/j.molimm.2017.10.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/14/2017] [Accepted: 10/20/2017] [Indexed: 12/28/2022]
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24
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Ichimura K, Shimizu T, Matsumoto A, Hirai S, Yokoyama E, Takeuchi H, Yahiro K, Noda M. Nitric oxide-enhanced Shiga toxin production was regulated by Fur and RecA in enterohemorrhagic Escherichia coli O157. Microbiologyopen 2017; 6. [PMID: 28294553 PMCID: PMC5552940 DOI: 10.1002/mbo3.461] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/20/2017] [Accepted: 02/01/2017] [Indexed: 12/27/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) produces Shiga toxin 1 (Stx1) and Shiga toxin 2 (Stx2). Nitric oxide (NO), which acts as an antimicrobial defense molecule, was found to enhance the production of Stx1 and Stx2 in EHEC under anaerobic conditions. Although EHEC O157 has two types of anaerobic NO reductase genes, an intact norV and a deleted norV, in the deleted norV‐type EHEC, a high concentration of NO (12–29 μmol/L, maximum steady‐state concentration) is required for enhanced Stx1 production and a low concentration of NO (~12 μmol/L, maximum steady‐state concentration) is sufficient for enhanced Stx2 production under anaerobic conditions. These results suggested that different concentration thresholds of NO elicit a discrete set of Stx1 and Stx2 production pathways. Moreover, the enhancement of Shiga toxin production in the intact norV‐type EHEC required treatment with a higher concentration of NO than was required for enhancement of Shiga toxin production in the deleted norV‐type EHEC, suggesting that the specific NorV type plays an important role in the level of enhancement of Shiga toxin production in response to NO. Finally, Fur derepression and RecA activation in EHEC were shown to participate in the NO‐enhanced Stx1 and Stx2 production, respectively.
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Affiliation(s)
- Kimitoshi Ichimura
- Departments of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Takeshi Shimizu
- Departments of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Akio Matsumoto
- Pharmacology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Shinichiro Hirai
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, Chiba, Japan
| | - Eiji Yokoyama
- Division of Bacteriology, Chiba Prefectural Institute of Public Health, Chiba, Japan
| | - Hiroki Takeuchi
- Departments of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Kinnosuke Yahiro
- Departments of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Masatoshi Noda
- Departments of Molecular Infectiology, Graduate School of Medicine, Chiba University, Chiba, Japan
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25
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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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26
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Kurt-Kızıldoğan A, Abanoz B, Okay S. Global transcriptome analysis of Halolamina sp. to decipher the salt tolerance in extremely halophilic archaea. Gene 2016; 601:56-64. [PMID: 27919704 DOI: 10.1016/j.gene.2016.11.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 11/17/2016] [Accepted: 11/30/2016] [Indexed: 12/21/2022]
Abstract
Extremely halophilic archaea survive in the hypersaline environments such as salt lakes or salt mines. Therefore, these microorganisms are good sources to investigate the molecular mechanisms underlying the tolerance to high salt concentrations. In this study, a global transcriptome analysis was conducted in an extremely halophilic archaeon, Halolamina sp. YKT1, isolated from a salt mine in Turkey. A comparative RNA-seq analysis was performed using YKT1 isolate grown either at 2.7M NaCl or 5.5M NaCl concentrations. A total of 2149 genes were predicted to be up-regulated and 1638 genes were down-regulated in the presence of 5.5M NaCl. The salt tolerance of Halolamina sp. YKT1 involves the up-regulation of genes related with membrane transporters, CRISPR-Cas systems, osmoprotectant solutes, oxidative stress proteins, and iron metabolism. On the other hand, the genes encoding the proteins involved in DNA replication, transcription, translation, mismatch and nucleotide excision repair were down-regulated. The RNA-seq data were verified for seven up-regulated genes as well as six down-regulated genes via qRT-PCR analysis. This comprehensive transcriptome analysis showed that the halophilic archaeon canalizes its energy towards keeping the intracellular osmotic balance minimizing the production of nucleic acids and peptides.
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Affiliation(s)
- Aslıhan Kurt-Kızıldoğan
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139 Samsun, Turkey
| | - Büşra Abanoz
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayıs University, 55139 Samsun, Turkey
| | - Sezer Okay
- Department of Biology, Faculty of Science, Çankırı Karatekin University, 18100 Çankırı, Turkey.
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27
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Hepatic mobilization of zinc after an experimental surgery, and its relationship with inflammatory cytokines release, and expression of metallothionein and Zip14 transporter. Inflamm Res 2016; 66:167-175. [DOI: 10.1007/s00011-016-1003-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 08/04/2016] [Accepted: 10/21/2016] [Indexed: 11/26/2022] Open
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28
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Darrigo C, Guillemet E, Dervyn R, Ramarao N. The Bacterial Mfd Protein Prevents DNA Damage Induced by the Host Nitrogen Immune Response in a NER-Independent but RecBC-Dependent Pathway. PLoS One 2016; 11:e0163321. [PMID: 27711223 PMCID: PMC5053507 DOI: 10.1371/journal.pone.0163321] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 09/07/2016] [Indexed: 11/28/2022] Open
Abstract
Production of reactive nitrogen species is an important component of the host immune defence against bacteria. Here, we show that the bacterial protein Mfd (Mutation frequency decline), a highly conserved and ubiquitous bacterial protein involved in DNA repair, confers bacterial resistance to the eukaryotic nitrogen response produced by macrophage cells and during mice infection. In addition, we show that RecBC is also necessary to survive this stress. The inactivation of recBC and mfd genes is epistatic showing that Mfd follows the RecBC repair pathway to protect the bacteria against the genotoxic effect of nitrite. Surprisingly given the role of Mfd in transcription-coupled repair, UvrA is not necessary to survive the nitrite response. Taken together, our data reveal that during the eukaryotic nitrogen response, Mfd is required to maintain bacterial genome integrity in a NER-independent but RecBC-dependent pathway.
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Affiliation(s)
- Claire Darrigo
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Elisabeth Guillemet
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Rozenn Dervyn
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Nalini Ramarao
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
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29
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Abstract
Pathogenic bacteria must withstand diverse host environments during infection. Environmental signals, such as pH, temperature, nutrient limitation, etc., not only trigger adaptive responses within bacteria to these specific stress conditions but also direct the expression of virulence genes at an appropriate time and place. An appreciation of stress responses and their regulation is therefore essential for an understanding of bacterial pathogenesis. This review considers specific stresses in the host environment and their relevance to pathogenesis, with a particular focus on the enteric pathogen Salmonella.
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Affiliation(s)
- Ferric C Fang
- Department of Microbiology, University of Washington School of Medicine, Seattle, WA 98195-7735, USA; Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195-7735, USA.
| | - Elaine R Frawley
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle, WA 98195-7735, USA
| | - Timothy Tapscott
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Andrés Vázquez-Torres
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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The bacterial DNA repair protein Mfd confers resistance to the host nitrogen immune response. Sci Rep 2016; 6:29349. [PMID: 27435260 PMCID: PMC4951645 DOI: 10.1038/srep29349] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 06/17/2016] [Indexed: 01/23/2023] Open
Abstract
Production of reactive nitrogen species (NO) is a key step in the immune response following infections. NO induces lesions to bacterial DNA, thus limiting bacterial growth within hosts. Using two pathogenic bacteria, Bacillus cereus and Shigella flexneri, we show that the DNA-repair protein Mfd (Mutation-Frequency-Decline) is required for bacterial resistance to the host-NO-response. In both species, a mutant deficient for mfd does not survive to NO, produced in vitro or by phagocytic cells. In vivo, the ∆mfd mutant is avirulent and unable to survive the NO-stress. Moreover, NO induces DNA-double-strand-breaks and point mutations in the Δmfd mutant. In overall, these observations demonstrate that NO damages bacterial DNA and that Mfd is required to maintain bacterial genomic integrity. This unexpected discovery reveals that Mfd, a typical housekeeping gene, turns out to be a true virulence factor allowing survival and growth of the pathogen in its host, due to its capacity to protect the bacterium against NO, a key molecule of the innate immune defense. As Mfd is widely conserved in the bacterial kingdom, these data highlight a mechanism that may be used by a large spectrum of bacteria to overcome the host immune response and especially the mutagenic properties of NO.
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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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Runkel S, Wells HC, Rowley G. Living with Stress: A Lesson from the Enteric Pathogen Salmonella enterica. ADVANCES IN APPLIED MICROBIOLOGY 2016; 83:87-144. [PMID: 23651595 DOI: 10.1016/b978-0-12-407678-5.00003-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The ability to sense and respond to the environment is essential for the survival of all living organisms. Bacterial pathogens such as Salmonella enterica are of particular interest due to their ability to sense and adapt to the diverse range of conditions they encounter, both in vivo and in environmental reservoirs. During this cycling from host to non-host environments, Salmonella encounter a variety of environmental insults ranging from temperature fluctuations, nutrient availability and changes in osmolarity, to the presence of antimicrobial peptides and reactive oxygen/nitrogen species. Such fluctuating conditions impact on various areas of bacterial physiology including virulence, growth and antimicrobial resistance. A key component of the success of any bacterial pathogen is the ability to recognize and mount a suitable response to the discrete chemical and physical stresses elicited by the host. Such responses occur through a coordinated and complex programme of gene expression and protein activity, involving a range of transcriptional regulators, sigma factors and two component regulatory systems. This review briefly outlines the various stresses encountered throughout the Salmonella life cycle and the repertoire of regulatory responses with which Salmonella counters. In particular, how these Gram-negative bacteria are able to alleviate disruption in periplasmic envelope homeostasis through a group of stress responses, known collectively as the Envelope Stress Responses, alongside the mechanisms used to overcome nitrosative stress, will be examined in more detail.
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Affiliation(s)
- Sebastian Runkel
- School of Biological Sciences, University of East Anglia, Norwich, UK
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A novel nitro-dexamethasone inhibits agr system activity and improves therapeutic effects in MRSA sepsis models without antibiotics. Sci Rep 2016; 6:20307. [PMID: 26839286 PMCID: PMC4738243 DOI: 10.1038/srep20307] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 12/30/2015] [Indexed: 12/13/2022] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) sepsis is a life-threatening medical condition that involves systemic inflammation throughout the body. Glucocorticoids are widely used in combination with antibiotics in the treatment of MRSA sepsis to fight the overwhelming inflammation. Here, we describe the improved anti-inflammatory properties of a nitric oxide (NO)-releasing derivative of dexamethasone, ND8008. ND8008 affected MRSA biofilm formation, caused biofilm cell death, and reduced the effects of virulence factors, such as α-toxin, by inhibiting the activity of the Staphylococcus aureus accessory gene regulator (agr) system. Dosing of mice with ND8008 (127.4 nmol/kg, i.p.) alone greatly reduced the inflammatory response caused by MRSA blood stream infection and considerably increased the survival rate of septic mice. These findings suggest that this novel NO-releasing derivative of dexamethasone ND8008 could be helpful in the treatment of MRSA sepsis.
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Tikhomirova A, Jiang D, Kidd SP. A new insight into the role of intracellular nickel levels for the stress response, surface properties and twitching motility by Haemophilus influenzae. Metallomics 2016; 7:650-61. [PMID: 25350148 DOI: 10.1039/c4mt00245h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nickel acts as a co-factor for a small number of enzymes in bacteria. Urease is one of the two nickel-dependent enzymes that have been identified in Haemophilus influenzae; glyoxalase I is the other. However, nickel has been suggested to have roles in H. influenzae that can not attributed to the function of these enzymes. We have previously shown that in the H. influenzae strain Rd KW20 the inability to acquire nickel led to alterations to the cell-type; an increased biofilm formation and changes in cell surface properties. Here we report the differences in the genome wide gene expression between Rd KW20 and a strain incapable of importing nickel (nikQ); revealing a link between intracellular nickel levels and genes involved in metabolic pathways, stress responses and genes associated with surface factors such as type IV pili. We have then taken a strain previously shown to use type IV pili both in biofilm formation and for twitching motility (86-028NP) and have shown its homologous genes (NTHI1417-1422; annotated as cobalt transporter, cbiKLMOQ) did import nickel and mutations in this locus had pleiotropic effects correlating to stress response and motility. Compared to wild type cells, the nickel depleted cells were more electronegativity charged, they aggregated and formed a biofilm. Correct intracellular nickel levels were also important for resistance to oxidative stress; the nickel depleted cells were more sensitive to oxidative stress. The nickel depleted cells were also non-motile, but the addition specifically of nickel returned these cells to a wild type motility state. We have also analysed the role of nickel uptake in a naturally, urease negative strain (the blood isolate R2866) and depleting intracellular nickel (a nikQ mutant) in this strain effected a similar range of cell functions. These data reveal a role for the capacity to acquire nickel from the environment and for the correct intracellular nickel levels as part of H. influenzae stress response and in signalling for a switch to a sessile bacterial lifestyle.
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Affiliation(s)
- Alexandra Tikhomirova
- Research Centre for Infectious Disease, School of Molecular and Biomedical Science, The University of Adelaide, Adelaide, 5005, Australia.
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Alpha CJ, Campos M, Jacobs-Wagner C, Strobel SA. Mycofumigation by the volatile organic compound-producing Fungus Muscodor albus induces bacterial cell death through DNA damage. Appl Environ Microbiol 2015; 81:1147-56. [PMID: 25452287 PMCID: PMC4292491 DOI: 10.1128/aem.03294-14] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/24/2014] [Indexed: 12/18/2022] Open
Abstract
Muscodor albus belongs to a genus of endophytic fungi that inhibit and kill other fungi, bacteria, and insects through production of a complex mixture of volatile organic compounds (VOCs). This process of mycofumigation has found commercial application for control of human and plant pathogens, but the mechanism of the VOC toxicity is unknown. Here, the mode of action of these volatiles was investigated through a series of genetic screens and biochemical assays. A single-gene knockout screen revealed high sensitivity for Escherichia coli lacking enzymes in the pathways of DNA repair, DNA metabolic process, and response to stress when exposed to the VOCs of M. albus. Furthermore, the sensitivity of knockouts involved in the repair of specific DNA alkyl adducts suggests that the VOCs may induce alkylation. Evidence of DNA damage suggests that these adducts lead to breaks during DNA replication or transcription if not properly repaired. Additional cytotoxicity profiling indicated that during VOC exposure, E. coli became filamentous and demonstrated an increase in cellular membrane fluidity. The volatile nature of the toxic compounds produced by M. albus and their broad range of inhibition make this fungus an attractive biological agent. Understanding the antimicrobial effects and the VOC mode of action will inform the utility and safety of potential mycofumigation applications for M. albus.
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Affiliation(s)
- Cambria J Alpha
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Manuel Campos
- Microbial Diversity Institute, Department of Molecular, Cellular and Developmental Biology, and Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, USA
| | - Christine Jacobs-Wagner
- Microbial Diversity Institute, Department of Molecular, Cellular and Developmental Biology, and Howard Hughes Medical Institute, Yale University, New Haven, Connecticut, USA
| | - Scott A Strobel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
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Lu S. Zn2+ blocks annealing of complementary single-stranded DNA in a sequence-selective manner. Sci Rep 2014; 4:5464. [PMID: 24965053 PMCID: PMC4071324 DOI: 10.1038/srep05464] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/11/2014] [Indexed: 12/19/2022] Open
Abstract
Zinc is the second most abundant trace element essential for all living organisms. In human body, 30–40% of the total zinc ion (Zn2+) is localized in the nucleus. Intranuclear free Zn2+ sparks caused by reactive oxygen species have been observed in eukaryotic cells, but question if these free Zn2+ outrages could have affected annealing of complementary single-stranded (ss) DNA, a crucial step in DNA synthesis, repair and recombination, has never been raised. Here the author reports that Zn2+ blocks annealing of complementary ssDNA in a sequence-selective manner under near-physiological conditions as demonstrated in vitro using a low-temperature EDTA-free agarose gel electrophoresis (LTEAGE) procedure. Specifically, it is shown that Zn2+ does not block annealing of repetitive DNA sequences lacking CG/GC sites that are the major components of junk DNA. It is also demonstrated that Zn2+ blocks end-joining of double-stranded (ds) DNA fragments with 3′ overhangs mimicking double-strand breaks, and prevents renaturation of long stretches (>1 kb) of denatured dsDNA, in which Zn2+-tolerant intronic DNA provides annealing protection on otherwise Zn2+-sensitive coding DNA. These findings raise a challenging hypothesis that Zn2+-ssDNA interaction might be among natural forces driving eukaryotic genomes to maintain the Zn2+-tolerant repetitive DNA for adapting to the Zn2+-rich nucleus.
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Affiliation(s)
- Shunwen Lu
- USDA-ARS, Cereal Crops Research Unit, Fargo, ND 58102, USA
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Lin CD, Kou YY, Liao CY, Li CH, Huang SP, Cheng YW, Liao WC, Chen HX, Wu PL, Kang JJ, Lee CC, Lai CH. Zinc oxide nanoparticles impair bacterial clearance by macrophages. Nanomedicine (Lond) 2014; 9:1327-39. [PMID: 24628689 DOI: 10.2217/nnm.14.48] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM The extensive development of nanoparticles (NPs) and their widespread employment in daily life have led to an increase in environmental concentrations of substances that may pose a biohazard to humans. The aim of this work was to examine the effects of zinc oxide nanoparticles (ZnO-NPs) on the host's pulmonary immune system response to nontypeable Haemophilus influenzae (NTHi) infection. MATERIALS & METHODS A murine infection model was employed to assess pulmonary inflammation and bacterial clearance in response to exposure to ZnO-NPs. The molecular mechanisms underlying ZnO-NP-impaired macrophage activation were investigated. RESULTS Treatment with ZnO-NPs impaired macrophage activation, leading to a delay in NTHi clearance in the bronchial alveolar lavage fluids and lungs. Exposure to ZnO-NPs followed by NTHi challenge decreased levels of nitric oxide compared with NTHi infection alone. The effects of ZnO-NPs involved downregulation of NTHi-activated expression of inducible nitric oxide synthase and the translocation of active NF-kB into the nucleus. CONCLUSION These results demonstrate that exposure to ZnO-NPs can impair innate immune responses and attenuate macrophage responses to bacterial infection.
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Affiliation(s)
- Chia-Der Lin
- Department of Otolaryngology-Head & Neck Surgery, China Medical University Hospital, Taichung, Taiwan
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Stern AM, Zhu J. An introduction to nitric oxide sensing and response in bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2014; 87:187-220. [PMID: 24581392 DOI: 10.1016/b978-0-12-800261-2.00005-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nitric oxide (NO) is a radical gas that has been intensively studied for its role as a bacteriostatic agent. NO reacts in complex ways with biological molecules, especially metal centers and other radicals, to generate other bioactive compounds that inhibit enzymes, oxidize macromolecules, and arrest bacterial growth. Bacteria encounter not only NO derived from the host during infection but also NO derived from other bacteria and inorganic sources. The transcriptional responses used by bacteria to respond to NO are diverse but usually involve an iron-containing transcription factor that binds NO and alters its affinity for either DNA or factors involved in transcription, leading to the production of enzymatic tolerance systems. Some of these systems, such as flavohemoglobin and flavorubredoxin, directly remove NO. Some do not but are still important for NO tolerance through other mechanisms. The targets of NO that are protected by these systems include many metabolic pathways such as the tricarboxylic acid cycle and branched chain amino acid synthesis. This chapter discusses these topics and others and serves as a general introduction to microbial NO biology.
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Lyu LD, Tang BK, Fan XY, Ma H, Zhao GP. Mycobacterial MazG safeguards genetic stability via housecleaning of 5-OH-dCTP. PLoS Pathog 2013; 9:e1003814. [PMID: 24339782 PMCID: PMC3855555 DOI: 10.1371/journal.ppat.1003814] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/23/2013] [Indexed: 01/05/2023] Open
Abstract
Generation of reactive oxygen species and reactive nitrogen species in phagocytes is an important innate immune response mechanism to eliminate microbial pathogens. It is known that deoxynucleotides (dNTPs), the precursor nucleotides to DNA synthesis, are one group of the significant targets for these oxidants and incorporation of oxidized dNTPs into genomic DNA may cause mutations and even cell death. Here we show that the mycobacterial dNTP pyrophosphohydrolase MazG safeguards the bacilli genome by degrading 5-OH-dCTP, thereby, preventing it from incorporation into DNA. Deletion of the (d)NTP pyrophosphohydrolase-encoding mazG in mycobacteria leads to a mutator phenotype both under oxidative stress and in the stationary phase of growth, resulting in increased CG to TA mutations. Biochemical analyses demonstrate that mycobacterial MazG can efficiently hydrolyze 5-OH-dCTP, an oxidized nucleotide that induces CG to TA mutation upon incorporation by polymerase. Moreover, chemical genetic analyses show that direct incorporation of 5-OH-dCTP into mazG-null mutant strain of Mycobacterium smegmatis (Msm) leads to a dose-dependent mutagenesis phenotype, indicating that 5-OH-dCTP is a natural substrate of mycobacterial MazG. Furthermore, deletion of mazG in Mycobacterium tuberculosis (Mtb) leads to reduced survival in activated macrophages and in the spleen of infected mice. This study not only characterizes the mycobacterial MazG as a novel pyrimidine-specific housecleaning enzyme that prevents CG to TA mutation by degrading 5-OH-dCTP but also reveals a genome-safeguarding mechanism for survival of Mtb in vivo. The cellular nucleotide pool is a significant target for oxidation by reactive oxygen species and reactive nitrogen species. Misincorporation of these oxidized non-canonical nucleotides into DNA is known to cause mutations, and may be related to carcinogenesis, aging and neurodegeneration. Cells have evolved a group of bio-degradation housecleaning enzymes that may specifically eliminate certain non-canonical nucleotide from the nucleotide pool and thus prevent their incorporation into DNA. The most well-characterized housecleaning enzymes are the MutT-like proteins which specifically hydrolyze the oxidized purine nucleotides, such as 8-oxo-dGTP and 2-OH-dATP. Lack of MutT activity in cells leads to significant increase of AT-CG mutation and genetic instability. However, housecleaning enzymes specific for oxidized pyrimidine nucleotides are yet to be identified. Here we show that the dNTP pyrophosphohydrolase MazG from mycobacteria is a 5-OH-dCTP-specific housecleaning enzyme. Deletion of mazG in mycobacteria results in increased CG to TA mutation under oxidative stress and in the stationary phase of growth. Both biochemical and chemical genetic analyses demonstrate that 5-OH-dCTP is a natural substrate of mycobacterial MazG. Furthermore, deletion of mazG in Mtb leads to reduced survival in activated macrophages and in the spleen of infected mice. These results reveal a novel housecleaning pathway for mycobacteria to maintain genetic stability and survival in vivo.
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Affiliation(s)
- Liang-Dong Lyu
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Department of Microbiology and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
- * E-mail: (LDL); (GPZ)
| | - Bi-Kui Tang
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Anhui Key Laboratory of Infection and Immunity, Department of Life Science, Bengbu Medical College, Bengbu, China
| | - Xiao-Yong Fan
- Shanghai Public Health Clinical Center Affiliated with Fudan University, Shanghai, China
| | - Hui Ma
- Shanghai Public Health Clinical Center Affiliated with Fudan University, Shanghai, China
| | - Guo-Ping Zhao
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Department of Microbiology and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
- Key Laboratory of Medical Molecular Virology affiliated with the Ministry of Education and Health, Shanghai Medical College, Department of Microbiology, School of Life Sciences, Fudan University, Shanghai, China
- Shanghai-MOST Key Laboratory for Health and Disease Genomics, Chinese National Human Genome Center, Shanghai, China
- * E-mail: (LDL); (GPZ)
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Abstract
SIGNIFICANCE In bacteria, transcriptional responses to reactive oxygen and nitrogen species (ROS and RNS, respectively) are typically coordinated by regulatory proteins that employ metal centers or reactive thiols to detect the presence of those species. This review is focused on the structure, function and mechanism of three regulatory proteins (Fur, PerR, and NorR) that contain non-heme iron and regulate the transcription of target genes in response to ROS and/or RNS. The targets for regulation include genes encoding detoxification activities, and genes encoding proteins involved in the repair of the damage caused by ROS and RNS. RECENT ADVANCES Three-dimensional structures of several Fur proteins and of PerR are revealing important details of the metal binding sites of these proteins, showing a surprising degree of structural diversity in the Fur family. CRITICAL ISSUES Discussion of the interaction of Fur with ROS and RNS will illustrate the difficulty that sometimes exists in distinguishing between true physiological responses and adventitious reactions of a regulatory protein with a reactive ligand. FUTURE DIRECTIONS Consideration of these three sensor proteins illuminates some of the key questions that remain unanswered, for example, the nature of the biochemical determinants that dictate the sensitivity and specificity of the interaction of the sensor proteins with their cognate signals.
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Affiliation(s)
- Stephen Spiro
- Department of Molecular and Cell Biology, University of Texas at Dallas, Richardson, Texas 75080, USA.
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Ponnusamy D, Clinkenbeard KD. Yersinia pestis intracellular parasitism of macrophages from hosts exhibiting high and low severity of plague. PLoS One 2012; 7:e42211. [PMID: 22848745 PMCID: PMC3407133 DOI: 10.1371/journal.pone.0042211] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 07/03/2012] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Yersinia pestis causes severe disease in natural rodent hosts, but mild to inapparent disease in certain rodent predators such as dogs. Y. pestis initiates infection in susceptible hosts by parasitizing and multiplying intracellularly in local macrophages prior to systemic dissemination. Thus, we hypothesize that Y. pestis disease severity may depend on the degree to which intracellular Y. pestis overcomes the initial host macrophage imposed stress. METHODOLOGY/PRINCIPAL FINDINGS To test this hypothesis, the progression of in vitro infection by Y. pestis KIM62053.1+ of mouse splenic and RAW264.7 tissue culture macrophages and dog peripheral blood-derived and DH82 tissue culture macrophages was studied using microscopy and various parameters of infection. The study showed that during the early stage of infection, intracellular Y. pestis assumed filamentous cellular morphology with multiple copies of the genome per bacterium in both mouse and dog macrophages. Later, in mouse macrophages, the infection elicited spacious vacuolar extension of Yersinia containing vacuoles (YCV), and the filamentous Y. pestis reverted to coccobacillary morphology with genomic equivalents approximately equaling colony forming units. In contrast, Y. pestis infected dog macrophages did not show noticeable extension of YCV, and intracellular Y. pestis retained the filamentous cellular morphology for the entire experiment in DH82 cells or were killed by blood-derived macrophages. In addition, during the later stage of infection, Y. pestis infected mouse macrophages exhibited cell lysis whereas dog macrophages did not. CONCLUSION/SIGNIFICANCE Overall, these results support our hypothesis that Y. pestis in mouse macrophages can overcome the initial intracellular stress necessary for subsequent systemic infection. However, in dogs, failure of Y. pestis to overcome macrophage imposed stress may result in mild or in apparent disease in dogs.
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Affiliation(s)
- Duraisamy Ponnusamy
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Kenneth D. Clinkenbeard
- Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma, United States of America
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Vitamin B12-mediated restoration of defective anaerobic growth leads to reduced biofilm formation in Pseudomonas aeruginosa. Infect Immun 2012; 80:1639-49. [PMID: 22371376 DOI: 10.1128/iai.06161-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Pseudomonas aeruginosa undergoes cell elongation and forms robust biofilms during anaerobic respiratory growth using nitrate (NO(3)(-)) as an alternative electron acceptor. Understanding the mechanism of cell shape change induced upon anaerobiosis is crucial to the development of effective treatments against P. aeruginosa biofilm infection. Here, we uncovered the molecular basis of anaerobiosis-triggered cell elongation and identified vitamin B(12) to be a molecule that can reinstate defective anaerobic growth of P. aeruginosa. The ratio of total cellular DNA content to protein content was significantly decreased in the PAO1 strain grown under anaerobic conditions, indicating that DNA replication is impaired during anaerobic growth. Anaerobic growth of PAO1 reached a higher cell density in the presence of vitamin B(12), an essential coenzyme of class II ribonucleotide reductase. In addition, cell morphology returned to a normal rod shape and transcription of stress-response genes was downregulated under the same anaerobic growth conditions. These results suggest that vitamin B(12), the production of which was suppressed during anaerobic growth, can restore cellular machineries for DNA replication and therefore facilitate better anaerobic growth of P. aeruginosa with normal cell division. Importantly, biofilm formation was substantially decreased when grown with vitamin B(12), further demonstrating that anaerobiosis-induced cell elongation is responsible for robust biofilm formation. Taken together, our data reveal mechanistic details of a morphological change that naturally occurs during anaerobic growth of P. aeruginosa and illustrates the ability of vitamin B(12) to modulate the biofilm-forming capacity of P. aeruginosa under such condition.
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Goclaw-Binder H, Sendersky E, Shimoni E, Kiss V, Reich Z, Perelman A, Schwarz R. Nutrient-associated elongation and asymmetric division of the cyanobacterium Synechococcus PCC 7942. Environ Microbiol 2011; 14:680-90. [DOI: 10.1111/j.1462-2920.2011.02620.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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The role of DNA base excision repair in filamentation in Escherichia coli K-12 adhered to epithelial HEp-2 cells. Antonie van Leeuwenhoek 2011; 101:423-31. [PMID: 21965040 DOI: 10.1007/s10482-011-9649-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/20/2011] [Indexed: 12/19/2022]
Abstract
Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species generated by chemical and physical agents or by metabolism which can react with DNA and cause a variety of mutations. Epithelial cells are typically the first type of host cell to come into contact with potential microbial invaders. In this work, we have evaluated whether the adherence to human epithelial cells causes DNA damage and associated filamentation. Experiments concerning adherence to HEp-2 cells were carried out with mutants deficient in BER that were derived from Escherichia coli K-12. Since the removal of mannose during bacterial interaction with HEp-2 cells allows adhesion through mannose-sensitive adhesins, the experiments were also performed in the presence and the absence of mannose. Our results showed enhanced filamentation for the single xth (BW9091) and triple xth nfo nth (BW535) mutants in adherence assays with HEp-2 cells performed without D: -mannose. The increased filamentation growth was inhibited by complementation of BER mutants with a wild type xth gene. Moreover, we measured SOS induction of bacteria adhered to HEp-2 cells in the presence and absence of D: -mannose through of SOS-chromotest assay and we observed a higher β-galactosidase expression in the absence of mannose. In this context, data showed evidence that bacterial attachment to HEp-2 epithelial surfaces can generate DNA lesions and SOS induction.
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Abstract
Everything should be as simple as it can be, but not simpler. —Attributed to Albert Einstein (1)
Reactive oxygen species (ROS) are produced by host phagocytes and exert antimicrobial actions against a broad range of pathogens. The observable antimicrobial actions of ROS are highly dependent on experimental conditions. This perspective reviews recent controversies regarding ROS in Salmonella-phagocyte interactions and attempts to reconcile conflicting observations from different laboratories.
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Mraheil MA, Billion A, Mohamed W, Rawool D, Hain T, Chakraborty T. Adaptation of Listeria monocytogenes to oxidative and nitrosative stress in IFN-γ-activated macrophages. Int J Med Microbiol 2011; 301:547-55. [PMID: 21697010 DOI: 10.1016/j.ijmm.2011.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 03/29/2011] [Accepted: 05/01/2011] [Indexed: 11/26/2022] Open
Abstract
IFN-γ-activated macrophages are considered to be the primary effector cells in host defense against Listeria monocytogenes infections. However despite the induction of the complex host defense mechanisms, survival of L. monocytogenes in activated macrophages is still observed. Here we used a whole genome-based transcriptome approach to examine for bacterial genes specifically induced in IFN-γ-activated macrophages. We demonstrated that cells activated by IFN-γ had elevated oxidative and nitrosative stress levels in both the activated macrophages as well as in the intracellular replicating bacteria isolated from these infected cells. We found that a subset of 21 transcripts were specifically differentially regulated in bacteria growing in cells pretreated with IFN-γ. Bioinformatics and functional analysis revealed that many of these genes have roles involved in overcoming oxidative stress and contribute to bacterial survival within activated macrophages. We detected increased transcription of the putative trpE gene of L. monocytogenes, encoding an anthranilate synthase, in bacteria growing in IFN-γ cells indicating host cell metabolic restriction of bacterial growth. Indeed we found enhanced activation of host cell genes involved in the kynurenine pathway indicating an increased need of L. monocytogenes for tryptophan during replication in IFN-γ-activated macrophages.
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Affiliation(s)
- Mobarak Abu Mraheil
- Institute for Medical Microbiology, Justus-Liebig-University, Giessen, Germany.
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Bourret TJ, Boylan JA, Lawrence KA, Gherardini FC. Nitrosative damage to free and zinc-bound cysteine thiols underlies nitric oxide toxicity in wild-type Borrelia burgdorferi. Mol Microbiol 2011; 81:259-73. [PMID: 21564333 PMCID: PMC3147059 DOI: 10.1111/j.1365-2958.2011.07691.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Borrelia burgdorferi encounters potentially harmful reactive nitrogen species (RNS) throughout its infective cycle. In this study, diethylamine NONOate (DEA/NO) was used to characterize the lethal effects of RNS on B. burgdorferi. RNS produce a variety of DNA lesions in a broad spectrum of microbial pathogens; however, levels of the DNA deamination product, deoxyinosine, and the numbers of apurinic/apyrimidinic (AP) sites were identical in DNA isolated from untreated and DEA/NO-treated B. burgdorferi cells. Strains with mutations in the nucleotide excision repair (NER) pathway genes uvrC or uvrB treated with DEA/NO had significantly higher spontaneous mutation frequencies, increased numbers of AP sites in DNA and reduced survival compared with wild-type controls. Polyunsaturated fatty acids in B. burgdorferi cell membranes, which are susceptible to peroxidation by reactive oxygen species (ROS), were not sensitive to RNS-mediated lipid peroxidation. However, treatment of B. burgdorferi cells with DEA/NO resulted in nitrosative damage to several proteins, including the zinc-dependent glycolytic enzyme fructose-1,6-bisphosphate aldolase (BB0445), the Borrelia oxidative stress regulator (BosR) and neutrophil-activating protein (NapA). Collectively, these data suggested that nitrosative damage to proteins harbouring free or zinc-bound cysteine thiols, rather than DNA or membrane lipids underlies RNS toxicity in wild-type B. burgdorferi.
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Affiliation(s)
- Travis J Bourret
- Laboratory of Zoonotic Pathogens, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT 59840, USA
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Qu W, Zhou Y, Sun Y, Fang M, Yu H, Li W, Liu Z, Zeng J, Chen C, Gao C, Jia J. Identification of S-nitrosylation of proteins of Helicobacter pylori in response to nitric oxide stress. J Microbiol 2011; 49:251-6. [PMID: 21538246 DOI: 10.1007/s12275-011-0262-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 11/10/2010] [Indexed: 12/16/2022]
Abstract
Innate and adaptive immune responses are activated in humans when Helicobacter pylori invades the gastric mucosa. Nitric oxide (NO) and reactive nitrogen species are important immune effectors, which can exert their functions through oxidation and S-nitrosylation of proteins. S-nitrosoglutathione and sodium nitroprus-side were used as NO donors and H. pylori cells were incubated with these compounds to analyze the inhibitory effect of NO. The suppressing effect of NO on H. pylori has been shown in vitro. Furthermore, the proteins modified by S-nitrosylation in H. pylori were identified through the biotin switch method in association with matrix-assisted laser desorption ionization/time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS). Five S-nitrosylated proteins identified were a chaperone and heat-shock protein (GroEL), alkyl hydroperoxide reductase (TsaA), urease alpha subunit (UreA), HP0721, and HP0129. Importantly, S-nitrosylation of TsaA and UreA were confirmed using purified recombinant proteins. Considering the importance of these enzymes in antioxidant defenses, adherence, and colonization, NO may exert its antibacterial actions by targeting enzymes through S-nitrosylation. Identification of protein S-nitrosylation may contribute to an understanding of the antibacterial actions of NO. Our findings provide an insight into potential targets for the development of novel therapeutic agents against H. pylori infection.
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Affiliation(s)
- Wei Qu
- Department of Microbiology and Immunology, Key Laboratory for Experimental Teratology of Chinese Ministry of Education, School of Medicine, Shandong University, Jinan, Shandong 250012, P R China
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Henard CA, Vázquez-Torres A. Nitric oxide and salmonella pathogenesis. Front Microbiol 2011; 2:84. [PMID: 21833325 PMCID: PMC3153045 DOI: 10.3389/fmicb.2011.00084] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 04/08/2011] [Indexed: 12/12/2022] Open
Abstract
Nitric oxide (NO) and its congeners contribute to the innate immune response to Salmonella. This enteric pathogen is exposed to reactive nitrogen species (RNS) in the environment and at different anatomical locations during its infectious cycle in vertebrate hosts. Chemical generation of RNS enhances the gastric barrier to enteropathogenic bacteria, while products of the Salmonella pathogenicity island 1 type III secretion system and Salmonella-associated molecular patterns stimulate transcription of inducible NO synthase (iNOS) by cells of the mononuclear phagocytic cell lineage. The resulting NO, or products that arise from its interactions with oxygen (O2) or iron and low-molecular weight thiols, are preferentially bacteriostatic against Salmonella, while reaction of NO and superoxide (O2−) generates the bactericidal compound peroxynitrite (ONOO−). The anti-Salmonella activity of RNS emanates from the modification of redox active thiols and metal prosthetic groups of key molecular targets of the electron transport chain, central metabolic enzymes, transcription factors, and DNA and DNA-associated proteins. In turn, Salmonella display a plethora of defenses that modulate the delivery of iNOS-containing vesicles to phagosomes, scavenge and detoxify RNS, and repair biomolecules damaged by these toxic species. Traditionally, RNS have been recognized as important mediators of host defense against Salmonella. However, exciting new findings indicate that Salmonella can exploit the RNS produced during the infection to foster virulence. More knowledge of the primary RNS produced in response to Salmonella infection, the bacterial processes affected by these toxic species, and the adaptive bacterial responses that protect Salmonella from nitrosative and oxidative stress associated with NO will increase our understanding of Salmonella pathogenesis. This information may assist in the development of novel therapeutics against this common enteropathogen.
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Affiliation(s)
- Calvin A Henard
- Department of Microbiology, University of Colorado School of Medicine Aurora, CO, USA
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Privett BJ, Deupree SM, Backlund CJ, Rao KS, Johnson CB, Coneski PN, Schoenfisch MH. Synergy of nitric oxide and silver sulfadiazine against gram-negative, gram-positive, and antibiotic-resistant pathogens. Mol Pharm 2010; 7:2289-96. [PMID: 20939612 DOI: 10.1021/mp100248e] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The synergistic activity between nitric oxide (NO) released from diazeniumdiolate-modified proline (PROLI/NO) and silver(I) sulfadiazine (AgSD) was evaluated against Escherichia coli, Enterococcus faecalis, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis using a modified broth microdilution technique and a checkerboard-type assay. The combination of NO and AgSD was defined as synergistic when the fractional bactericidal concentration (FBC) was calculated to be <0.5. Gram-negative species were generally more susceptible to the individual antimicrobial agents than the Gram-positive bacteria, while Gram-positive bacteria were more susceptible to combination therapy. The in vitro synergistic activity of AgSD and NO observed against a range of pathogens strongly supports future investigation of this therapeutic combination, particularly for its potential use in the treatment of burns and chronic wounds.
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Affiliation(s)
- Benjamin J Privett
- Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina 27599, United States
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