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Howell A, Chogule S, Djoko KY. Copper homeostasis in Streptococcus and Neisseria: Known knowns and unknown knowns. Adv Microb Physiol 2025; 86:99-140. [PMID: 40404273 DOI: 10.1016/bs.ampbs.2024.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2025]
Abstract
Our research group studies copper (Cu) homeostasis in Streptococcus and Neisseria, with a current focus on species that colonise the human oral cavity. Our early ventures into this field very quickly revealed major differences between well-characterised Cu homeostasis systems in species with well-known pathogenic potential and the uncharacterised systems in species that are considered as components of the normal healthy human microflora. In this article, we summarise the known and predicted mechanisms of Cu homeostasis in Streptococcus and Neisseria. We focus exclusively on proteins that directly sense and change (increase or decrease) cellular Cu availability. Where relevant, we make comparisons with examples from species isolated from outside the human oral cavity and from animal hosts. The emerging picture depicts diverse cellular strategies for handling Cu, even among closely related bacterial species.
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Affiliation(s)
- Archie Howell
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Safa Chogule
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Karrera Y Djoko
- Department of Biosciences, Durham University, Durham, United Kingdom.
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2
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Diaz Dilernia F, Watson D, Heinrichs D, Vasarhelyi E. The antimicrobial properties of exogenous copper in human synovial fluid against Staphylococcus aureus. Bone Joint Res 2024; 13:632-646. [PMID: 39504990 PMCID: PMC11540464 DOI: 10.1302/2046-3758.1311.bjr-2024-0148.r1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2024] Open
Abstract
Aims The mechanism by which synovial fluid (SF) kills bacteria has not yet been elucidated, and a better understanding is needed. We sought to analyze the antimicrobial properties of exogenous copper in human SF against Staphylococcus aureus. Methods We performed in vitro growth and viability assays to determine the capability of S. aureus to survive in SF with the addition of 10 µM of copper. We determined the minimum bactericidal concentration of copper (MBC-Cu) and evaluated its sensitivity to killing, comparing wild type (WT) and CopAZB-deficient USA300 strains. Results UAMS-1 demonstrated a greater sensitivity to SF compared to USA300 WT at 12 hours (p = 0.001) and 24 hours (p = 0.027). UAMS-1 died in statistically significant quantities at 24 hours (p = 0.017), and USA300 WT survived at 24 hours. UAMS-1 was more susceptible to the addition of copper at four (p = 0.001), 12 (p = 0.005), and 24 hours (p = 0.006). We confirmed a high sensitivity to killing with the addition of exogenous copper on both strains at four (p = 0.011), 12 (p = 0.011), and 24 hours (p = 0.011). WT and CopAZB-deficient USA300 strains significantly died in SF, demonstrating a MBC-Cu of 50 µM against USA300 WT (p = 0.011). Conclusion SF has antimicrobial properties against S. aureus, and UAMS-1 was more sensitive than USA300 WT. Adding 10 µM of copper was highly toxic, confirming its bactericidal effect. We found CopAZB proteins to be involved in copper effluxion by demonstrating the high sensitivity of mutant strains to lower copper concentrations. Thus, we propose CopAZB proteins as potential targets and use exogenous copper as a treatment alternative against S. aureus.
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Affiliation(s)
- Fernando Diaz Dilernia
- Adult Hip and Knee Reconstructive Surgery, London Health Sciences Centre, Division of Orthopedic Surgery, Department of Surgery, Schulich School of Medicine & Dentistry, Western University, London, Canada
- Division of Orthopedic Surgery, Department of Surgery, Kingston Health Sciences Center, Queen’s University, Kingston, Canada
| | - David Watson
- Adult Hip and Knee Reconstructive Surgery, London Health Sciences Centre, Division of Orthopedic Surgery, Department of Surgery, Schulich School of Medicine & Dentistry, Western University, London, Canada
| | - David Heinrichs
- Adult Hip and Knee Reconstructive Surgery, London Health Sciences Centre, Division of Orthopedic Surgery, Department of Surgery, Schulich School of Medicine & Dentistry, Western University, London, Canada
| | - Edward Vasarhelyi
- Adult Hip and Knee Reconstructive Surgery, London Health Sciences Centre, Division of Orthopedic Surgery, Department of Surgery, Schulich School of Medicine & Dentistry, Western University, London, Canada
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3
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Rivera-Millot A, Harrison LB, Veyrier FJ. Copper management strategies in obligate bacterial symbionts: balancing cost and benefit. Emerg Top Life Sci 2024; 8:29-35. [PMID: 38095549 PMCID: PMC10903467 DOI: 10.1042/etls20230113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/22/2023] [Accepted: 11/26/2023] [Indexed: 02/23/2024]
Abstract
Bacteria employ diverse mechanisms to manage toxic copper in their environments, and these evolutionary strategies can be divided into two main categories: accumulation and rationalization of metabolic pathways. The strategies employed depend on the bacteria's lifestyle and environmental context, optimizing the metabolic cost-benefit ratio. Environmental and opportunistically pathogenic bacteria often possess an extensive range of copper regulation systems in order to respond to variations in copper concentrations and environmental conditions, investing in diversity and/or redundancy as a safeguard against uncertainty. In contrast, obligate symbiotic bacteria, such as Neisseria gonorrhoeae and Bordetella pertussis, tend to have specialized and more parsimonious copper regulation systems designed to function in the relatively stable host environment. These evolutionary strategies maintain copper homeostasis even in challenging conditions like encounters within phagocytic cells. These examples highlight the adaptability of bacterial copper management systems, tailored to their specific lifestyles and environmental requirements, in the context of an evolutionary the trade-off between benefits and energy costs.
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Affiliation(s)
- Alex Rivera-Millot
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, Quebec H7V 1B7, Canada
| | - Luke B. Harrison
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, Quebec H7V 1B7, Canada
| | - Frédéric J. Veyrier
- INRS-Centre Armand-Frappier Santé Biotechnologie, Bacterial Symbionts Evolution, Laval, Quebec H7V 1B7, Canada
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4
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Yun Z, Xianghong L, Qianhua G, Qin D. Copper ions inhibit Streptococcus mutans-Veillonella parvula dual biofilm by activating Streptococcus mutans reactive nitrogen species. BMC Oral Health 2023; 23:48. [PMID: 36709299 PMCID: PMC9883903 DOI: 10.1186/s12903-023-02738-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Accepted: 01/11/2023] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND To investigate the inhibition mechanism of copper ions on Streptococcus mutans-Veillonella parvula dual biofilm. METHODS S. mutans-V. parvula dual biofilm was constructed and copper ions were added at different concentrations. After the biofilm was collected, RNA-seq and qRT-PCR were then performed to get gene information. RESULTS The coculture of S. mutans and V. parvula formed a significantly better dual biofilm of larger biomass than S. mutans mono biofilm. And copper ions showed a more significant inhibitory effect on S. mutans-V. parvula dual biofilm than on S. mutans mono biofilm when copper ions concentration reached 100 µM, and copper ions showed a decreased inhibitory effect on S. gordonii-V. parvula dual biofilm and S. sanguis-V.parvula dual biofilm than on the two mono biofilms as the concentration of copper ions increased. And common trace elements such as iron, magnesium, and zinc showed no inhibitory effect difference on S. mutans-V. parvula dual biofilm. The RNA-seq results showed a significant difference in the expression of a new ABC transporter SMU_651c, SMU_652c, SMU_653c, and S. mutans copper chaperone copYAZ. SMU_651c, SMU_652c, and SMU_653c were predicted to function as nitrite/nitrate transporter-related proteins, which suggested the specific inhibition of copper ions on S. mutans-V. parvula dual biofilm may be caused by the activation of S. mutans reactive nitrogen species. CONCLUSIONS Streptococcus mutans and Veillonella parvula are symbiotic, forming a dual biofilm of larger biomass to better resist the external antibacterial substances, which may increase the virulence of S. mutans. While common trace elements such as iron, magnesium, and zinc showed no specific inhibitory effect on S. mutans-V. parvula dual biofilm, copper ion had a unique inhibitory effect on S. mutans-V. parvula dual biofilm which may be caused by activating S. mutans RNS when copper ions concentration reached 250 µM.
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Affiliation(s)
- Zhang Yun
- grid.13291.380000 0001 0807 1581State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, 610041 Sichuan China ,grid.13291.380000 0001 0807 1581Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041 Sichuan China
| | - Liu Xianghong
- grid.54549.390000 0004 0369 4060Department of Stomatology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 610072 China
| | - Gao Qianhua
- grid.54549.390000 0004 0369 4060Department of Stomatology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 610072 China
| | - Du Qin
- grid.54549.390000 0004 0369 4060Department of Stomatology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, 610072 China
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Host-Mediated Copper Stress Is Not Protective against Streptococcus pneumoniae D39 Infection. Microbiol Spectr 2022; 10:e0249522. [PMID: 36413018 PMCID: PMC9769658 DOI: 10.1128/spectrum.02495-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Metal ions are required by all organisms for the chemical processes that support life. However, in excess they can also exert toxicity within biological systems. During infection, bacterial pathogens such as Streptococcus pneumoniae are exposed to host-imposed metal intoxication, where the toxic properties of metals, such as copper, are exploited to aid in microbial clearance. However, previous studies investigating the antimicrobial efficacy of copper in vivo have reported variable findings. Here, we use a highly copper-sensitive strain of S. pneumoniae, lacking both copper efflux and intracellular copper buffering by glutathione, to investigate how copper stress is managed and where it is encountered during infection. We show that this strain exhibits highly dysregulated copper homeostasis, leading to the attenuation of growth and hyperaccumulation of copper in vitro. In a murine infection model, whole-tissue copper quantitation and elemental bioimaging of the murine lung revealed that infection with S. pneumoniae resulted in increased copper abundance in specific tissues, with the formation of spatially discrete copper hot spots throughout the lung. While the increased copper was able to reduce the viability of the highly copper-sensitive strain in a pneumonia model, copper levels in professional phagocytes and in a bacteremic model were insufficient to prosecute bacterial clearance. Collectively, this study reveals that host copper is redistributed to sites of infection and can impact bacterial viability in a hypersusceptible strain. However, in wild-type S. pneumoniae, the concerted actions of the copper homeostatic mechanisms are sufficient to facilitate continued viability and virulence of the pathogen. IMPORTANCE Streptococcus pneumoniae (the pneumococcus) is one of the world's foremost bacterial pathogens. Treatment of both localized and systemic pneumococcal infection is becoming complicated by increasing rates of multidrug resistance globally. Copper is a potent antimicrobial agent used by the mammalian immune system in the defense against bacterial pathogens. However, unlike other bacterial species, this copper stress is unable to prosecute pneumococcal clearance. This study determines how the mammalian host inflicts copper stress on S. pneumoniae and the bacterial copper tolerance mechanisms that contribute to maintenance of viability and virulence in vitro and in vivo. This work has provided insight into the chemical biology of the host-pneumococcal interaction and identified a potential avenue for novel antimicrobial development.
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6
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Focarelli F, Giachino A, Waldron KJ. Copper microenvironments in the human body define patterns of copper adaptation in pathogenic bacteria. PLoS Pathog 2022; 18:e1010617. [PMID: 35862345 PMCID: PMC9302775 DOI: 10.1371/journal.ppat.1010617] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Copper is an essential micronutrient for most organisms that is required as a cofactor for crucial copper-dependent enzymes encoded by both prokaryotes and eukaryotes. Evidence accumulated over several decades has shown that copper plays important roles in the function of the mammalian immune system. Copper accumulates at sites of infection, including the gastrointestinal and respiratory tracts and in blood and urine, and its antibacterial toxicity is directly leveraged by phagocytic cells to kill pathogens. Copper-deficient animals are more susceptible to infection, whereas those fed copper-rich diets are more resistant. As a result, copper resistance genes are important virulence factors for bacterial pathogens, enabling them to detoxify the copper insult while maintaining copper supply to their essential cuproenzymes. Here, we describe the accumulated evidence for the varied roles of copper in the mammalian response to infections, demonstrating that this metal has numerous direct and indirect effects on immune function. We further illustrate the multifaceted response of pathogenic bacteria to the elevated copper concentrations that they experience when invading the host, describing both conserved and species-specific adaptations to copper toxicity. Together, these observations demonstrate the roles of copper at the host–pathogen interface and illustrate why bacterial copper detoxification systems can be viable targets for the future development of novel antibiotic drug development programs. Copper is required by both animals and bacteria in small quantities as a micronutrient. During infection, the mammalian immune system increases the local concentration of copper, which gives rise to copper toxicity in the pathogen. In turn, bacterial pathogens possess specialized systems to resist this copper toxicity. Copper also plays important, indirect roles in the function of the immune system. In this review, we explain the diverse roles of copper in the human body with a focus on its functions within the immune system. We also describe how bacterial pathogens respond to the copper toxicity that they experience within the host during infection, illustrating both conserved copper homeostasis and detoxification systems in bacteria and species-specific adaptations that have been shown to be important to pathogenicity. The key role of copper at the host–pathogen interface and the essential requirement for pathogenic bacteria to resist copper toxicity makes the protein components that confer resistance on pathogens potential targets for future development of novel antibiotic drugs.
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Affiliation(s)
- Francesca Focarelli
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrea Giachino
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kevin John Waldron
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail:
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7
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Branch AH, Stoudenmire JL, Seib KL, Cornelissen CN. Acclimation to Nutritional Immunity and Metal Intoxication Requires Zinc, Manganese, and Copper Homeostasis in the Pathogenic Neisseriae. Front Cell Infect Microbiol 2022; 12:909888. [PMID: 35846739 PMCID: PMC9280163 DOI: 10.3389/fcimb.2022.909888] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/18/2022] [Indexed: 12/15/2022] Open
Abstract
Neisseria gonorrhoeae and Neisseria meningitidis are human-specific pathogens in the Neisseriaceae family that can cause devastating diseases. Although both species inhabit mucosal surfaces, they cause dramatically different diseases. Despite this, they have evolved similar mechanisms to survive and thrive in a metal-restricted host. The human host restricts, or overloads, the bacterial metal nutrient supply within host cell niches to limit pathogenesis and disease progression. Thus, the pathogenic Neisseria require appropriate metal homeostasis mechanisms to acclimate to such a hostile and ever-changing host environment. This review discusses the mechanisms by which the host allocates and alters zinc, manganese, and copper levels and the ability of the pathogenic Neisseria to sense and respond to such alterations. This review will also discuss integrated metal homeostasis in N. gonorrhoeae and the significance of investigating metal interplay.
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Affiliation(s)
- Alexis Hope Branch
- Center for Translational Immunology, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
| | - Julie L. Stoudenmire
- Center for Translational Immunology, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
| | - Kate L. Seib
- Institute for Glycomics, Griffith University, Gold Coast, QLD, Australia
| | - Cynthia Nau Cornelissen
- Center for Translational Immunology, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, United States
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8
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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: 0.7] [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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9
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Malych R, Füssy Z, Ženíšková K, Arbon D, Hampl V, Hrdý I, Sutak R. The response of Naegleria gruberi to oxidative stress. Metallomics 2022; 14:6527579. [PMID: 35150262 DOI: 10.1093/mtomcs/mfac009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 02/06/2022] [Indexed: 11/14/2022]
Abstract
Aerobic organisms require oxygen for respiration but must simultaneously cope with oxidative damages inherently linked with this molecule. Unicellular amoeboflagellates of the genus Naegleria, containing both free-living species and opportunistic parasite, thrive in aerobic environments. However, they are also known to maintain typical features of anaerobic organisms. Here, we describe the mechanisms of oxidative damage mitigation in Naegleria gruberi and focus on the molecular characteristics of three noncanonical proteins interacting with oxygen and its derived reactive forms. We show that this protist expresses hemerythrin, protoglobin and an aerobic-type rubrerythrin, with spectral properties characteristic of the cofactors they bind. We provide evidence that protoglobin and hemerythrin interact with oxygen in vitro and confirm the mitochondrial localization of rubrerythrin by immunolabeling. Our proteomic analysis and immunoblotting following heavy metal treatment revealed upregulation of hemerythrin, while rotenone treatment resulted in an increase in rubrerythrin protein levels together with vast upregulation of alternative oxidase. Our study provided new insights into the mechanisms employed by N. gruberi to cope with different types of oxidative stress and allowed us to propose specific roles for three unique and understudied proteins: hemerythrin, protoglobin and rubrerythrin.
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Affiliation(s)
- Ronald Malych
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Zoltán Füssy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Kateřina Ženíšková
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Dominik Arbon
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Vladimír Hampl
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Robert Sutak
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
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10
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Hyre A, Casanova-Hampton K, Subashchandrabose S. Copper Homeostatic Mechanisms and Their Role in the Virulence of Escherichia coli and Salmonella enterica. EcoSal Plus 2021; 9:eESP00142020. [PMID: 34125582 PMCID: PMC8669021 DOI: 10.1128/ecosalplus.esp-0014-2020] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Copper is an essential micronutrient that also exerts toxic effects at high concentrations. This review summarizes the current state of knowledge on copper handling and homeostasis systems in Escherichia coli and Salmonella enterica. We describe the mechanisms by which transcriptional regulators, efflux pumps, detoxification enzymes, metallochaperones, and ancillary copper response systems orchestrate cellular response to copper stress. E. coli and S. enterica are important pathogens of humans and animals. We discuss the critical role of copper during killing of these pathogens by macrophages and in nutritional immunity at the bacterial-pathogen-host interface. In closing, we identify opportunities to advance our understanding of the biological roles of copper in these model enteric bacterial pathogens.
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Affiliation(s)
- Amanda Hyre
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC
| | - Kaitlin Casanova-Hampton
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Sargurunathan Subashchandrabose
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
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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: 1.3] [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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12
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Copper intoxication in group B Streptococcus triggers transcriptional activation of the cop operon that contributes to enhanced virulence during acute infection. J Bacteriol 2021; 203:e0031521. [PMID: 34251869 DOI: 10.1128/jb.00315-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria can utilize Copper (Cu) as a trace element to support cellular processes; however, excess Cu can intoxicate bacteria. Here, we characterize the cop operon in group B streptococcus (GBS), and establish its role in evasion of Cu intoxication and the response to Cu stress on virulence. Growth of GBS mutants deficient in either the copA Cu exporter, or the copY repressor, were severely compromised in Cu-stress conditions. GBS survival of Cu stress reflected a mechanism of CopY de-repression of the CopA efflux system. However, neither mutant was attenuated for intracellular survival in macrophages. Analysis of global transcriptional responses to Cu by RNA-sequencing revealed a stress signature encompassing homeostasis of multiple metals. Genes induced by Cu stress included putative metal transporters for manganese import, whereas a system for iron export was repressed. In addition, copA promoted the ability of GBS to colonize the blood, liver and spleen of mice following disseminated infection. Together, these findings show that GBS copA mediates resistance to Cu intoxication, via regulation by the Cu-sensing transcriptional repressor, copY. Cu stress responses in GBS reflect a transcriptional signature that heightens virulence and represents an important part of the bacteria's ability to survive in different environments. Importance Understanding how bacteria manage cellular levels of metal ions, such as copper, helps to explain how microbial cells can survive in different stressful environments. We show how the opportunistic pathogen group B Streptococcus (GBS) achieves homeostasis of intracellular copper through the activities of the genes that comprise the cop operon, and describe how this helps GBS survive in stressful environments, including in the mammalian host during systemic disseminated infection.
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13
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Culbertson EM, Khan AA, Muchenditsi A, Lutsenko S, Sullivan DJ, Petris MJ, Cormack BP, Culotta VC. Changes in mammalian copper homeostasis during microbial infection. Metallomics 2021; 12:416-426. [PMID: 31976503 DOI: 10.1039/c9mt00294d] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Animals carefully control homeostasis of Cu, a metal that is both potentially toxic and an essential nutrient. During infection, various shifts in Cu homeostasis can ensue. In mice infected with Candida albicans, serum Cu progressively rises and at late stages of infection, liver Cu rises, while kidney Cu declines. The basis for these changes in Cu homeostasis was poorly understood. We report here that the progressive rise in serum Cu is attributable to liver production of the multicopper oxidase ceruloplasmin (Cp). Through studies using Cp-/- mice, we find this elevated Cp helps recover serum Fe levels at late stages of infection, consistent with a role for Cp in loading transferrin with Fe. Cp also accounts for the elevation in liver Cu seen during infection, but not for the fluctuations in kidney Cu. The Cu exporting ATPase ATP7B is one candidate for kidney Cu control, but we find no change in the pattern of kidney Cu loss during infection of Atp7b-/- mice, implying alternative mechanisms. To test whether fungal infiltration of kidney tissue was required for kidney Cu loss, we explored other paradigms of infection. Infection with the intravascular malaria parasite Plasmodium berghei caused a rise in serum Cu and decrease in kidney Cu similar to that seen with C. albicans. Thus, dynamics in kidney Cu homeostasis appear to be a common feature among vastly different infection paradigms. The implications for such Cu homeostasis control in immunity are discussed.
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Affiliation(s)
- Edward M Culbertson
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Aslam A Khan
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Abigael Muchenditsi
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Svetlana Lutsenko
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - David J Sullivan
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Michael J Petris
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Valeria C Culotta
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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14
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Andrei A, Öztürk Y, Khalfaoui-Hassani B, Rauch J, Marckmann D, Trasnea PI, Daldal F, Koch HG. Cu Homeostasis in Bacteria: The Ins and Outs. MEMBRANES 2020; 10:E242. [PMID: 32962054 PMCID: PMC7558416 DOI: 10.3390/membranes10090242] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential trace element for all living organisms and used as cofactor in key enzymes of important biological processes, such as aerobic respiration or superoxide dismutation. However, due to its toxicity, cells have developed elaborate mechanisms for Cu homeostasis, which balance Cu supply for cuproprotein biogenesis with the need to remove excess Cu. This review summarizes our current knowledge on bacterial Cu homeostasis with a focus on Gram-negative bacteria and describes the multiple strategies that bacteria use for uptake, storage and export of Cu. We furthermore describe general mechanistic principles that aid the bacterial response to toxic Cu concentrations and illustrate dedicated Cu relay systems that facilitate Cu delivery for cuproenzyme biogenesis. Progress in understanding how bacteria avoid Cu poisoning while maintaining a certain Cu quota for cell proliferation is of particular importance for microbial pathogens because Cu is utilized by the host immune system for attenuating pathogen survival in host cells.
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Affiliation(s)
- Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
- Fakultät für Biologie, Albert-Ludwigs Universität Freiburg; Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | - Dorian Marckmann
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
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15
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Williams CL, Neu HM, Alamneh YA, Reddinger RM, Jacobs AC, Singh S, Abu-Taleb R, Michel SLJ, Zurawski DV, Merrell DS. Characterization of Acinetobacter baumannii Copper Resistance Reveals a Role in Virulence. Front Microbiol 2020; 11:16. [PMID: 32117089 PMCID: PMC7015863 DOI: 10.3389/fmicb.2020.00016] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
Acinetobacter baumannii is often highly drug-resistant and causes severe infections in compromised patients. These infections can be life threatening due to limited treatment options. Copper is inherently antimicrobial and increasing evidence indicates that copper containing formulations may serve as non-traditional therapeutics against multidrug-resistant bacteria. We previously reported that A. baumannii is sensitive to high concentrations of copper. To understand A. baumannii copper resistance at the molecular level, herein we identified putative copper resistance components and characterized 21 strains bearing mutations in these genes. Eight of the strains displayed a copper sensitive phenotype (pcoA, pcoB, copB, copA/cueO, copR/cusR, copS/cusS, copC, copD); the putative functions of these proteins include copper transport, oxidation, sequestration, and regulation. Importantly, many of these mutant strains still showed increased sensitivity to copper while in a biofilm. Inductively coupled plasma mass spectrometry revealed that many of these strains had defects in copper mobilization, as the mutant strains accumulated more intracellular copper than the wild-type strain. Given the crucial antimicrobial role of copper-mediated killing employed by the immune system, virulence of these mutant strains was investigated in Galleria mellonella; many of the mutant strains were attenuated. Finally, the cusR and copD strains were also investigated in the murine pneumonia model; both were found to be important for full virulence. Thus, copper possesses antimicrobial activity against multidrug-resistant A. baumannii, and copper sensitivity is further increased when copper homeostasis mechanisms are interrupted. Importantly, these proteins are crucial for full virulence of A. baumannii and may represent novel drug targets.
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Affiliation(s)
- Caitlin L Williams
- Department of Microbiology & Immunology, Uniformed Services University, Bethesda, MD, United States
| | - Heather M Neu
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Yonas A Alamneh
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Ryan M Reddinger
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Anna C Jacobs
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Shweta Singh
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Rania Abu-Taleb
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Sarah L J Michel
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Baltimore, MD, United States
| | - Daniel V Zurawski
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - D Scott Merrell
- Department of Microbiology & Immunology, Uniformed Services University, Bethesda, MD, United States
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16
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Zhu T, McClure R, Harrison OB, Genco C, Massari P. Integrated Bioinformatic Analyses and Immune Characterization of New Neisseria gonorrhoeae Vaccine Antigens Expressed during Natural Mucosal Infection. Vaccines (Basel) 2019; 7:E153. [PMID: 31627489 PMCID: PMC6963464 DOI: 10.3390/vaccines7040153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 10/11/2019] [Accepted: 10/14/2019] [Indexed: 02/07/2023] Open
Abstract
There is an increasingly severe trend of antibiotic-resistant Neisseria gonorrhoeae strains worldwide and new therapeutic strategies are needed against this sexually-transmitted pathogen. Despite the urgency, progress towards a gonococcal vaccine has been slowed by a scarcity of suitable antigens, lack of correlates of protection in humans and limited animal models of infection. N. gonorrhoeae gene expression levels in the natural human host does not reflect expression in vitro, further complicating in vitro-basedvaccine analysis platforms. We designed a novel candidate antigen selection strategy (CASS), based on a reverse vaccinology-like approach coupled with bioinformatics. We utilized the CASS to mine gonococcal proteins expressed during human mucosal infection, reported in our previous studies, and focused on a large pool of hypothetical proteins as an untapped source of potential new antigens. Via two discovery and analysis phases (DAP), we identified 36 targets predicted to be immunogenic, membrane-associated proteins conserved in N. gonorrhoeae and suitable for recombinant expression. Six initial candidates were produced and used to immunize mice. Characterization of the immune responses indicated cross-reactive antibodies and serum bactericidal activity against different N. gonorrhoeae strains. These results support the CASS as a tool for the discovery of new vaccine candidates.
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Affiliation(s)
- Tianmou Zhu
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Ryan McClure
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | - Odile B Harrison
- Department of Zoology, University of Oxford, Oxford OX1 3SY, UK.
| | - Caroline Genco
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA.
| | - Paola Massari
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA.
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17
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CopA Protects Streptococcus suis against Copper Toxicity. Int J Mol Sci 2019; 20:ijms20122969. [PMID: 31216645 PMCID: PMC6628060 DOI: 10.3390/ijms20122969] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/15/2019] [Accepted: 06/16/2019] [Indexed: 12/17/2022] Open
Abstract
Streptococcus suis is a zoonotic pathogen that causes great economic losses to the swine industry and severe threats to public health. A better understanding of its physiology would contribute to the control of its infections. Although copper is an essential micronutrient for life, it is toxic to cells when present in excessive amounts. Herein, we provide evidence that CopA is required for S. suis resistance to copper toxicity. Quantitative PCR analysis showed that copA expression was specifically induced by copper. Growth curve analyses and spot dilution assays showed that the ΔcopA mutant was defective in media supplemented with elevated concentrations of copper. Spot dilution assays also revealed that CopA protected S. suis against the copper-induced bactericidal effect. Using inductively coupled plasma-optical emission spectroscopy, we demonstrated that the role of CopA in copper resistance was mediated by copper efflux. Collectively, our data indicated that CopA protects S. suis against the copper-induced bactericidal effect via copper efflux.
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18
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The role of metal ions in the virulence and viability of bacterial pathogens. Biochem Soc Trans 2019; 47:77-87. [PMID: 30626704 DOI: 10.1042/bst20180275] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/08/2018] [Accepted: 11/29/2018] [Indexed: 01/18/2023]
Abstract
Metal ions fulfil a plethora of essential roles within bacterial pathogens. In addition to acting as necessary cofactors for cellular proteins, making them indispensable for both protein structure and function, they also fulfil roles in signalling and regulation of virulence. Consequently, the maintenance of cellular metal ion homeostasis is crucial for bacterial viability and pathogenicity. It is therefore unsurprising that components of the immune response target and exploit both the essentiality of metal ions and their potential toxicity toward invading bacteria. This review provides a brief overview of the transition metal ions iron, manganese, copper and zinc during infection. These essential metal ions are discussed in the context of host modulation of bioavailability, bacterial acquisition and efflux, metal-regulated virulence factor expression and the molecular mechanisms that contribute to loss of viability and/or virulence during host-imposed metal stress.
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19
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Crawford CL, Dalecki AG, Narmore WT, Hoff J, Hargett AA, Renfrow MB, Zhang M, Kalubowilage M, Bossmann SH, Queern SL, Lapi SE, Hunter RN, Bao D, Augelli-Szafran CE, Kutsch O, Wolschendorf F. Pyrazolopyrimidinones, a novel class of copper-dependent bactericidal antibiotics against multi-drug resistant S. aureus. Metallomics 2019; 11:784-798. [DOI: 10.1039/c8mt00316e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pyrazolopyrimidinones traffic copper into S. aureus, depleting ATP and altering essential ion concentrations, resulting in the death of the bacteria.
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Affiliation(s)
| | - Alex G. Dalecki
- Department of Medicine
- University of Alabama at Birmingham
- Birmingham
- USA
| | | | - Jessica Hoff
- Department of Medicine
- University of Alabama at Birmingham
- Birmingham
- USA
| | - Audra A. Hargett
- Department of Biochemistry and Molecular Genetics
- University of Alabama at Birmingham
- Birmingham
- USA
| | - Matthew B. Renfrow
- Department of Biochemistry and Molecular Genetics
- University of Alabama at Birmingham
- Birmingham
- USA
| | - Man Zhang
- Department of Chemistry
- Kansas State University
- Manhattan
- USA
| | | | | | - Stacy L. Queern
- Department of Radiology
- University of Alabama at Birmingham
- Birmingham
- USA
- Department of Chemistry
| | - Suzanne E. Lapi
- Department of Radiology
- University of Alabama at Birmingham
- Birmingham
- USA
- Department of Chemistry
| | - Robert N. Hunter
- Department of Chemistry
- Drug Discovery Division
- Southern Research
- Birmingham
- USA
| | - Donghui Bao
- Department of Chemistry
- Drug Discovery Division
- Southern Research
- Birmingham
- USA
| | | | - Olaf Kutsch
- Department of Medicine
- University of Alabama at Birmingham
- Birmingham
- USA
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20
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Marsh JW, Djoko KY, McEwan AG, Huston WM. Copper(II)-bis(thiosemicarbazonato) complexes as anti-chlamydial agents. Pathog Dis 2018; 75:4033033. [PMID: 28830076 DOI: 10.1093/femspd/ftx084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 07/20/2017] [Indexed: 11/14/2022] Open
Abstract
Lipophilic copper (Cu)-containing complexes have shown promising antibacterial activity against a range of bacterial pathogens. To examine the susceptibility of the intracellular human pathogen Chlamydia trachomatis to copper complexes containing bis(thiosemicarbazone) ligands [Cu(btsc)], we tested the in vitro effect of CuII-diacetyl- and CuII-glyoxal-bis[N(4)-methylthiosemicarbazonato] (Cu(atsm) and Cu(gtsm), respectively) on C. trachomatis. Cu(atsm) and to a greater extent, Cu(gtsm), prevented the formation of infectious chlamydial progeny. Impacts on host cell viability and respiration were also observed in addition to the Chlamydia impacts. This work suggests that copper-based complexes may represent a new lead approach for future development of new therapeutics against chlamydial infections, although host cell impacts need to be fully explored.
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Affiliation(s)
- James W Marsh
- The iThree Institute, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia
| | - Karrera Y Djoko
- School of Chemistry and Molecular Biosciences and Australian Centre for Infectious Disease Research, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Alastair G McEwan
- School of Chemistry and Molecular Biosciences and Australian Centre for Infectious Disease Research, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Wilhelmina M Huston
- School of Life Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW 2007, Australia
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21
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Cytoplasmic Copper Detoxification in Salmonella Can Contribute to SodC Metalation but Is Dispensable during Systemic Infection. J Bacteriol 2017; 199:JB.00437-17. [PMID: 28924031 DOI: 10.1128/jb.00437-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/12/2017] [Indexed: 12/21/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a leading cause of foodborne disease worldwide. Severe infections result from the ability of S Typhimurium to survive within host immune cells, despite being exposed to various host antimicrobial factors. SodCI, a copper-zinc-cofactored superoxide dismutase, is required to defend against phagocytic superoxide. SodCII, an additional periplasmic superoxide dismutase, although produced during infection, does not function in the host. Previous studies suggested that CueP, a periplasmic copper binding protein, facilitates acquisition of copper by SodCII. CopA and GolT, both inner membrane ATPases that pump copper from the cytoplasm to the periplasm, are a source of copper for CueP. Using in vitro SOD assays, we found that SodCI can also utilize CueP to acquire copper. However, both SodCI and SodCII have a significant fraction of activity independent of CueP and cytoplasmic copper export. We utilized a series of mouse competition assays to address the in vivo role of CueP-mediated SodC activation. A copA golT cueP triple mutant was equally as competitive as the wild type, suggesting that sufficient SodCI is active to defend against phagocytic superoxide independent of CueP and cytoplasmic copper export. We also confirmed that a strain containing a modified SodCII, which is capable of complementing a sodCI deletion, was fully virulent in a copA golT cueP background competed against the wild type. These competitions also address the potential impact of cytoplasmic copper toxicity within the phagosome. Our data suggest that Salmonella does not encounter inhibitory concentrations of copper during systemic infection.IMPORTANCESalmonella is a leading cause of gastrointestinal disease worldwide. In severe cases, Salmonella can cause life-threatening systemic infections, particularly in very young children, the elderly, or people who are immunocompromised. To cause disease, Salmonella must survive the hostile environment inside host immune cells, a location in which most bacteria are killed. Our work examines how one particular metal, copper, is acquired by Salmonella to activate a protein important for survival within immune cells. At high levels, copper itself can inhibit Salmonella Using a strain of Salmonella that cannot detoxify intracellular copper, we also addressed the in vivo role of copper as an antimicrobial agent.
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22
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Jamrozy D, Coll F, Mather AE, Harris SR, Harrison EM, MacGowan A, Karas A, Elston T, Estée Török M, Parkhill J, Peacock SJ. Evolution of mobile genetic element composition in an epidemic methicillin-resistant Staphylococcus aureus: temporal changes correlated with frequent loss and gain events. BMC Genomics 2017; 18:684. [PMID: 28870171 PMCID: PMC5584012 DOI: 10.1186/s12864-017-4065-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/15/2017] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Horizontal transfer of mobile genetic elements (MGEs) that carry virulence and antimicrobial resistance genes mediates the evolution of methicillin-resistant Staphylococcus aureus, and the emergence of new MRSA clones. Most MRSA lineages show an association with specific MGEs and the evolution of MGE composition following clonal expansion has not been widely studied. RESULTS We investigated the genomes of 1193 S. aureus bloodstream isolates, 1169 of which were MRSA, collected in the UK and the Republic of Ireland between 2001 and 2010. The majority of isolates belonged to clonal complex (CC)22 (n = 923), which contained diverse MGEs including elements that were found in other MRSA lineages. Several MGEs showed variable distribution across the CC22 phylogeny, including two antimicrobial resistance plasmids (pWBG751-like and SAP078A-like, carrying erythromycin and heavy metal resistance genes, respectively), a pathogenicity island carrying the enterotoxin C gene and two phage types Sa1int and Sa6int. Multiple gains and losses of these five MGEs were identified in the CC22 phylogeny using ancestral state reconstruction. Analysis of the temporal distribution of the five MGEs between 2001 and 2010 revealed an unexpected reduction in prevalence of the two plasmids and the pathogenicity island, and an increase in the two phage types. This occurred across the lineage and was not correlated with changes in the relative prevalence of CC22, or of any sub-lineages within in. CONCLUSIONS Ancestral state reconstruction coupled with temporal trend analysis demonstrated that epidemic MRSA CC22 has an evolving MGE composition, and indicates that this important MRSA lineage has continued to adapt to changing selective pressure since its emergence.
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Affiliation(s)
- Dorota Jamrozy
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Francesc Coll
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | - Alison E. Mather
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES UK
| | - Simon R. Harris
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Ewan M. Harrison
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
| | - Alasdair MacGowan
- British Society for Antimicrobial Chemotherapy, B1 3NJ, Birmingham, UK
| | - Andreas Karas
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge, CB21 5XA UK
| | - Tony Elston
- Colchester Hospital University NHS Foundation Trust, Colchester, CO4 5JL UK
| | - M. Estée Török
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
- Public Health England, Clinical Microbiology and Public Health Laboratory, Cambridge, CB21 5XA UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ UK
| | - Julian Parkhill
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Sharon J. Peacock
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SA UK
- London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
- Department of Medicine, University of Cambridge, Addenbrooke’s Hospital, Cambridge, CB2 0QQ UK
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, CB2 0QQ UK
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23
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Abstract
Bacterial pathogens have evolved to exploit humans as a rich source of nutrients to support survival and replication. The pathways of bacterial metabolism that permit successful colonization are surprisingly varied and highlight remarkable metabolic flexibility. The constraints and immune pressures of distinct niches within the human body set the stage for understanding the mechanisms by which bacteria acquire critical nutrients. In this article we discuss how different bacterial pathogens carry out carbon and energy metabolism in the host and how they obtain or use key nutrients for replication and immune evasion.
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24
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Interplay between tolerance mechanisms to copper and acid stress in Escherichia coli. Proc Natl Acad Sci U S A 2017; 114:6818-6823. [PMID: 28611214 DOI: 10.1073/pnas.1620232114] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Copper (Cu) is a key antibacterial component of the host innate immune system and almost all bacterial species possess systems that defend against the toxic effects of excess Cu. The Cu tolerance system in Gram-negative bacteria is composed minimally of a Cu sensor (CueR) and a Cu export pump (CopA). The cueR and copA genes are encoded on the chromosome typically as a divergent but contiguous operon. In Escherichia coli, cueR and copA are separated by two additional genes, ybaS and ybaT, which confer glutamine (Gln)-dependent acid tolerance and contribute to the glutamate (Glu)-dependent acid resistance system in this organism. Here we show that Cu strongly inhibits growth of a ∆copA mutant strain in acidic cultures. We further demonstrate that Cu stress impairs the pathway for Glu biosynthesis via glutamate synthase, leading to decreased intracellular levels of Glu. Addition of exogenous Glu rescues the ∆copA mutant from Cu stress in acidic conditions. Gln is also protective but this relies on the activities of YbaS and YbaT. Notably, expression of both enzymes is up-regulated during Cu stress. These results demonstrate a link between Cu stress, acid stress, and Glu/Gln metabolism, establish a role for YbaS and YbaT in Cu tolerance, and suggest that subtle changes in core metabolic pathways may contribute to overcoming host-imposed copper toxicity.
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25
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Dalecki AG, Crawford CL, Wolschendorf F. Copper and Antibiotics: Discovery, Modes of Action, and Opportunities for Medicinal Applications. Adv Microb Physiol 2017; 70:193-260. [PMID: 28528648 DOI: 10.1016/bs.ampbs.2017.01.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Copper is a ubiquitous element in the environment as well as living organisms, with its redox capabilities and complexation potential making it indispensable for many cellular functions. However, these same properties can be highly detrimental to prokaryotes and eukaryotes when not properly controlled, damaging many biomolecules including DNA, lipids, and proteins. To restrict free copper concentrations, all bacteria have developed mechanisms of resistance, sequestering and effluxing labile copper to minimize its deleterious effects. This weakness is actively exploited by phagocytes, which utilize a copper burst to destroy pathogens. Though administration of free copper is an unreasonable therapeutic antimicrobial itself, due to insufficient selectivity between host and pathogen, small-molecule ligands may provide an opportunity for therapeutic mimicry of the immune system. By modulating cellular entry, complex stability, resistance evasion, and target selectivity, ligand/metal coordination complexes can synergistically result in high levels of antibacterial activity. Several established therapeutic drugs, such as disulfiram and pyrithione, display remarkable copper-dependent inhibitory activity. These findings have led to development of new drug discovery techniques, using copper ions as the focal point. High-throughput screens for copper-dependent inhibitors against Mycobacterium tuberculosis and Staphylococcus aureus uncovered several new compounds, including a new class of inhibitors, the NNSNs. In this review, we highlight the microbial biology of copper, its antibacterial activities, and mechanisms to discover new inhibitors that synergize with copper.
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Affiliation(s)
- Alex G Dalecki
- The University of Alabama at Birmingham, Birmingham, AL, United States
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26
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Abstract
Transition metals are required trace elements for all forms of life. Due to their unique inorganic and redox properties, transition metals serve as cofactors for enzymes and other proteins. In bacterial pathogenesis, the vertebrate host represents a rich source of nutrient metals, and bacteria have evolved diverse metal acquisition strategies. Host metal homeostasis changes dramatically in response to bacterial infections, including production of metal sequestering proteins and the bombardment of bacteria with toxic levels of metals. In response, bacteria have evolved systems to subvert metal sequestration and toxicity. The coevolution of hosts and their bacterial pathogens in the battle for metals has uncovered emerging paradigms in social microbiology, rapid evolution, host specificity, and metal homeostasis across domains. This review focuses on recent advances and open questions in our understanding of the complex role of transition metals at the host-pathogen interface.
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Affiliation(s)
- Lauren D Palmer
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37212;
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37212;
- Tennessee Valley Healthcare System, US Department of Veterans Affairs, Nashville, Tennessee 37212
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27
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Zheng C, Ren S, Xu J, Zhao X, Shi G, Wu J, Li J, Chen H, Bei W. Contribution of NADH oxidase to oxidative stress tolerance and virulence of Streptococcus suis serotype 2. Virulence 2016; 8:53-65. [PMID: 27315343 DOI: 10.1080/21505594.2016.1201256] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Streptococcus suis is a major swine and zoonotic pathogen that causes severe infections. Previously, we identified 2 Spx regulators in S. suis, and demonstrated that SpxA1 affects oxidative stress tolerance and virulence. However, the mechanism behind SpxA1 function remains unclear. In this study, we targeted 4 genes that were expressed at significantly reduced levels in the spxA1 mutant, to determine their specific roles in adaptation to oxidative stress and virulence potential. The Δnox strain exhibited impaired growth under oxidative stress conditions, suggesting that NADH oxidase is involved in oxidative stress tolerance. Using murine and pig infection models, we demonstrate for the first time that NADH oxidase is required for virulence in S. suis 2. Furthermore, the enzymatic activity of NADH oxidase has a key role in oxidative stress tolerance and a secondary role in virulence. Collectively, our findings reveal that NADH oxidase plays an important part in SpxA1 function and provide a new insight into the pathogenesis of S. suis 2.
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Affiliation(s)
- Chengkun Zheng
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
| | - Sujing Ren
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
| | - Jiali Xu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
| | - Xigong Zhao
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
| | - Guolin Shi
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
| | - Jianping Wu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China
| | - Jinquan Li
- d College of Food Science and Technology, Huazhong Agricultural University , Wuhan , China
| | - Huanchun Chen
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
| | - Weicheng Bei
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University , Wuhan , China.,b Key Laboratory of Development of Veterinary Diagnostic Products, Ministry of Agriculture, Huazhong Agricultural University , Wuhan , China.,c The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University , Wuhan , China
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Passalacqua KD, Charbonneau ME, O'Riordan MXD. Bacterial Metabolism Shapes the Host-Pathogen Interface. Microbiol Spectr 2016; 4:10.1128/microbiolspec.VMBF-0027-2015. [PMID: 27337445 PMCID: PMC4922512 DOI: 10.1128/microbiolspec.vmbf-0027-2015+10.1128/microbiolspec.vmbf-0027-2015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2024] Open
Abstract
Bacterial pathogens have evolved to exploit humans as a rich source of nutrients to support survival and replication. The pathways of bacterial metabolism that permit successful colonization are surprisingly varied and highlight remarkable metabolic flexibility. The constraints and immune pressures of distinct niches within the human body set the stage for understanding the mechanisms by which bacteria acquire critical nutrients. In this article we discuss how different bacterial pathogens carry out carbon and energy metabolism in the host and how they obtain or use key nutrients for replication and immune evasion.
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Affiliation(s)
- Karla D Passalacqua
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Marie-Eve Charbonneau
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Mary X D O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
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Passalacqua KD, Charbonneau ME, O'Riordan MXD. Bacterial Metabolism Shapes the Host-Pathogen Interface. Microbiol Spectr 2016; 4:10.1128/microbiolspec.VMBF-0027-2015. [PMID: 27337445 PMCID: PMC4922512 DOI: 10.1128/microbiolspec.vmbf-0027-2015 10.1128/microbiolspec.vmbf-0027-2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Indexed: 01/23/2024] Open
Abstract
Bacterial pathogens have evolved to exploit humans as a rich source of nutrients to support survival and replication. The pathways of bacterial metabolism that permit successful colonization are surprisingly varied and highlight remarkable metabolic flexibility. The constraints and immune pressures of distinct niches within the human body set the stage for understanding the mechanisms by which bacteria acquire critical nutrients. In this article we discuss how different bacterial pathogens carry out carbon and energy metabolism in the host and how they obtain or use key nutrients for replication and immune evasion.
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Affiliation(s)
- Karla D Passalacqua
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Marie-Eve Charbonneau
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
| | - Mary X D O'Riordan
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109
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30
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Dalecki AG, Malalasekera AP, Schaaf K, Kutsch O, Bossmann SH, Wolschendorf F. Combinatorial phenotypic screen uncovers unrecognized family of extended thiourea inhibitors with copper-dependent anti-staphylococcal activity. Metallomics 2016; 8:412-21. [PMID: 26935206 PMCID: PMC4838501 DOI: 10.1039/c6mt00003g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The continuous rise of multi-drug resistant pathogenic bacteria has become a significant challenge for the health care system. In particular, novel drugs to treat infections of methicillin-resistant Staphylococcus aureus strains (MRSA) are needed, but traditional drug discovery campaigns have largely failed to deliver clinically suitable antibiotics. More than simply new drugs, new drug discovery approaches are needed to combat bacterial resistance. The recently described phenomenon of copper-dependent inhibitors has galvanized research exploring the use of metal-coordinating molecules to harness copper's natural antibacterial properties for therapeutic purposes. Here, we describe the results of the first concerted screening effort to identify copper-dependent inhibitors of Staphylococcus aureus. A standard library of 10 000 compounds was assayed for anti-staphylococcal activity, with hits defined as those compounds with a strict copper-dependent inhibitory activity. A total of 53 copper-dependent hit molecules were uncovered, similar to the copper independent hit rate of a traditionally executed campaign conducted in parallel on the same library. Most prominent was a hit family with an extended thiourea core structure, termed the NNSN motif. This motif resulted in copper-dependent and copper-specific S. aureus inhibition, while simultaneously being well tolerated by eukaryotic cells. Importantly, we could demonstrate that copper binding by the NNSN motif is highly unusual and likely responsible for the promising biological qualities of these compounds. A subsequent chemoinformatic meta-analysis of the ChEMBL chemical database confirmed the NNSNs as an unrecognized staphylococcal inhibitor, despite the family's presence in many chemical screening libraries. Thus, our copper-biased screen has proven able to discover inhibitors within previously screened libraries, offering a mechanism to reinvigorate exhausted molecular collections.
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Affiliation(s)
- Alex G Dalecki
- Department of Medicine, University of Alabama at Birmingham, 845 19th Street S, Birmingham, AL 35294, USA.
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31
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Jen FEC, Djoko KY, Bent SJ, Day CJ, McEwan AG, Jennings MP. A genetic screen reveals a periplasmic copper chaperone required for nitrite reductase activity in pathogenicNeisseria. FASEB J 2015; 29:3828-38. [DOI: 10.1096/fj.15-270751] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/18/2015] [Indexed: 01/21/2023]
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Copper(II)-Bis(Thiosemicarbazonato) Complexes as Antibacterial Agents: Insights into Their Mode of Action and Potential as Therapeutics. Antimicrob Agents Chemother 2015; 59:6444-53. [PMID: 26239980 DOI: 10.1128/aac.01289-15] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 07/23/2015] [Indexed: 12/21/2022] Open
Abstract
There is increasing interest in the use of lipophilic copper (Cu)-containing complexes to combat bacterial infections. In this work, we showed that Cu complexes with bis(thiosemicarbazone) ligands [Cu(btsc)] exert antibacterial activity against a range of medically significant pathogens. Previous work using Neisseria gonorrhoeae showed that Cu(btsc) complexes may act as inhibitors of respiratory dehydrogenases in the electron transport chain. We now show that these complexes are also toxic against pathogens that lack a respiratory chain. Respiration in Escherichia coli was slightly affected by Cu(btsc) complexes, but our results indicate that, in this model bacterium, the complexes act primarily as agents that deliver toxic Cu ions efficiently into the cytoplasm. Although the chemistry of Cu(btsc) complexes may dictate their mechanism of action, their efficacy depends heavily on bacterial physiology. This is linked to the ability of the target bacterium to tolerate Cu and, additionally, the susceptibility of the respiratory chain to direct inhibition by Cu(btsc) complexes. The physiology of N. gonorrhoeae, including multidrug-resistant strains, makes it highly susceptible to damage by Cu ions and Cu(btsc) complexes, highlighting the potential of Cu(btsc) complexes (and Cu-based therapeutics) as a promising treatment against this important bacterial pathogen.
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Djoko KY, Ong CLY, Walker MJ, McEwan AG. The Role of Copper and Zinc Toxicity in Innate Immune Defense against Bacterial Pathogens. J Biol Chem 2015; 290:18954-61. [PMID: 26055706 DOI: 10.1074/jbc.r115.647099] [Citation(s) in RCA: 270] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Zinc (Zn) and copper (Cu) are essential for optimal innate immune function, and nutritional deficiency in either metal leads to increased susceptibility to bacterial infection. Recently, the decreased survival of bacterial pathogens with impaired Cu and/or Zn detoxification systems in phagocytes and animal models of infection has been reported. Consequently, a model has emerged in which the host utilizes Cu and/or Zn intoxication to reduce the intracellular survival of pathogens. This review describes and assesses the potential role for Cu and Zn intoxication in innate immune function and their direct bactericidal function.
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Affiliation(s)
- Karrera Y Djoko
- From the School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Cheryl-lynn Y Ong
- From the School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Mark J Walker
- From the School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Alastair G McEwan
- From the School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia
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Role of copper efflux in pneumococcal pathogenesis and resistance to macrophage-mediated immune clearance. Infect Immun 2015; 83:1684-94. [PMID: 25667262 DOI: 10.1128/iai.03015-14] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In bacteria, the intracellular levels of metals are mediated by tightly controlled acquisition and efflux systems. This is particularly true of copper, a trace element that is universally toxic in excess. During infection, the toxic properties of copper are exploited by the mammalian host to facilitate bacterial clearance. To better understand the role of copper during infection, we characterized the contribution of the cop operon to copper homeostasis and virulence in Streptococcus pneumoniae. Deletion of either the exporter, encoded by copA, or the chaperone, encoded by cupA, led to hypersensitivity to copper stress. We further demonstrated that loss of the copper exporter encoded by copA led to decreased virulence in pulmonary, intraperitoneal, and intravenous models of infection. Deletion of copA resulted in enhanced macrophage-mediated bacterial clearance in vitro. The attenuation phenotype of the copA mutant in the lung was found to be dependent on pulmonary macrophages, underscoring the importance of copper efflux in evading immune defenses. Overall, these data provide insight into the role of the cop operon in pneumococcal pathogenesis.
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Djoko KY, Paterson BM, Donnelly PS, McEwan AG. Antimicrobial effects of copper(II) bis(thiosemicarbazonato) complexes provide new insight into their biochemical mode of action. Metallomics 2014; 6:854-63. [PMID: 24435165 DOI: 10.1039/c3mt00348e] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The copper(II) complexes of bis-thiosemicarbazones (Cu(btsc)) such as Cu(atsm) and Cu(gtsm) are neutral, lipophilic compounds that show promise as therapeutics for the treatment of certain neurological diseases and cancers. Although the effects of these compounds have been described at the cellular level, there is almost no information about their biochemical mode of action. In this work, we showed that Cu(atsm) and Cu(gtsm) displayed antimicrobial activities against the human obligate pathogen Neisseria gonorrhoeae that were more than 100 times more potent than Cu(NO3)2 salt alone. Treatment with Cu(btsc) also produced phenotypes that were consistent with copper poisoning, but the levels of intracellular copper were undetectable by ICP MS. We observed that Cu(btsc) interacted with proteins in the cell membrane. Systematic measurements of O2 uptake further demonstrated that treatment with both Cu(atsm) and Cu(gtsm) led to dose-dependent inhibition of respiratory electron transfer processes via succinate and NADH dehydrogenases. These dehydrogenases were not inhibited by a non-btsc source of Cu(II). The results led us to conclude that the biochemical mechanism of Cu(btsc) action is likely more complex than the present, simplistic model of copper release into the cytoplasm.
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Affiliation(s)
- Karrera Y Djoko
- School of Chemistry and Molecular Biosciences and Australian Centre for Infectious Diseases Research, University of Queensland, Bdg 76 Cooper Road, St Lucia, QLD 4127, Australia.
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Metal ion homeostasis in Listeria monocytogenes and importance in host-pathogen interactions. Adv Microb Physiol 2014; 65:83-123. [PMID: 25476765 DOI: 10.1016/bs.ampbs.2014.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Listeria monocytogenes is responsible for one of the most life-threatening food-borne infections and the leading cause of food-poisoning associated deaths in the UK. Infection may be of the unborn/newly born infant where disease may manifest as listeric abortion, stillbirth or late-onset neonatal listeriosis, while in adults, infection usually affects the central nervous system causing meningitis. Crucial to the survival of L. monocytogenes, both inside and outside the host, is its ability to acquire metals which act as cofactors for a broad range of its cellular proteins. However, L. monocytogenes must also protect itself against the innate toxicity of metals. The importance of metals in host-pathogen interactions is illustrated by the restriction of metals (including zinc and iron) in vertebrates in response to infection and the use of high levels of metals (copper and zinc) as part of the antimicrobial defences within host phagocytes. As such, L. monocytogenes is equipped with various mechanisms to tightly control its cellular metal pools and avoid metal poisoning. These include multiple DNA-binding metal-responsive transcription factors, metal-acquisition, metal-detoxification and metal-storage systems, some of which represent key L. monocytogenes virulence determinants. This review discusses current knowledge of the role of metals in L. monocytogenes infections, with a focus on the mechanisms that contribute to zinc and copper homeostasis in this organism. The requirement to precisely control cellular metal levels may impose a vulnerability to L. monocytogenes which can be exploited in antimicrobials and therapeutics.
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Chaturvedi KS, Henderson JP. Pathogenic adaptations to host-derived antibacterial copper. Front Cell Infect Microbiol 2014; 4:3. [PMID: 24551598 PMCID: PMC3909829 DOI: 10.3389/fcimb.2014.00003] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 01/06/2014] [Indexed: 12/11/2022] Open
Abstract
Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu(+)) in its reduced form and copper (II) (Cu(2+)) in its oxidized form under physiologic conditions. Cu(+) is significantly more bactericidal than Cu(2+) due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it.
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Affiliation(s)
- Kaveri S Chaturvedi
- Division of Infectious Diseases, Department of Internal Medicine, Center for Women's Infectious Diseases Research, Washington University School of Medicine St. Louis, MO, USA
| | - Jeffrey P Henderson
- Division of Infectious Diseases, Department of Internal Medicine, Center for Women's Infectious Diseases Research, Washington University School of Medicine St. Louis, MO, USA
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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: 49] [Impact Index Per Article: 4.5] [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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Djoko KY, McEwan AG. Antimicrobial action of copper is amplified via inhibition of heme biosynthesis. ACS Chem Biol 2013; 8:2217-23. [PMID: 23895035 DOI: 10.1021/cb4002443] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Copper (Cu) is a potent antimicrobial agent. Its use as a disinfectant goes back to antiquity, but this metal ion has recently emerged to have a physiological role in the host innate immune response. Recent studies have identified iron-sulfur containing proteins as key targets for inhibition by Cu. However, the way in these effects at the molecular level translate into a global effect on cell physiology is not fully understood. Here, we provide a new insight into the way in which Cu poisons bacteria. Using a copA mutant of the obligate human pathogen Neisseria gonorrhoeae that lacks a Cu efflux pump, we showed that Cu overloading led to an increased sensitivity to hydrogen peroxide. However, instead of promoting disproportionation of H2O2 via Fenton chemistry, Cu treatment led to an increased lifetime of H2O2 in cultures as a result of a marked decrease in catalase activity. We showed that this observation correlated with a loss of intracellular heme. We further established that Cu inhibited the pathway for heme biosynthesis. We proposed that this impaired ability to produce heme during Cu stress would lead to the failure to activate hemoproteins that participate in key processes, such as the detoxification of various reactive oxygen and nitrogen species, and aerobic respiration. The impact would be a global disruption of cellular biochemistry and an amplified Cu toxicity.
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Affiliation(s)
- Karrera Y. Djoko
- School of Chemistry and Molecular
Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Alastair G. McEwan
- School of Chemistry and Molecular
Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
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40
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Szumowski JD, Adams KN, Edelstein PH, Ramakrishnan L. Antimicrobial efflux pumps and Mycobacterium tuberculosis drug tolerance: evolutionary considerations. Curr Top Microbiol Immunol 2013; 374:81-108. [PMID: 23242857 PMCID: PMC3859842 DOI: 10.1007/82_2012_300] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The need for lengthy treatment to cure tuberculosis stems from phenotypic drug resistance, also known as drug tolerance, which has been previously attributed to slowed bacterial growth in vivo. We discuss recent findings that challenge this model and instead implicate macrophage-induced mycobacterial efflux pumps in antimicrobial tolerance. Although mycobacterial efflux pumps may have originally served to protect against environmental toxins, in the pathogenic mycobacteria, they appear to have been repurposed for intracellular growth. In this light, we discuss the potential of efflux pump inhibitors such as verapamil to shorten tuberculosis treatment by their dual inhibition of tolerance and growth.
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Affiliation(s)
- John D Szumowski
- Department of Medicine (Division of Infectious Diseases), University of Washington, Seattle, WA, USA,
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41
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Nutritional immunity: transition metals at the pathogen-host interface. Nat Rev Microbiol 2012; 10:525-37. [PMID: 22796883 DOI: 10.1038/nrmicro2836] [Citation(s) in RCA: 1122] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Transition metals occupy an essential niche in biological systems. Their electrostatic properties stabilize substrates or reaction intermediates in the active sites of enzymes, and their heightened reactivity is harnessed for catalysis. However, this heightened activity also renders transition metals toxic at high concentrations. Bacteria, like all living organisms, must regulate their intracellular levels of these elements to satisfy their physiological needs while avoiding harm. It is therefore not surprising that the host capitalizes on both the essentiality and toxicity of transition metals to defend against bacterial invaders. This Review discusses established and emerging paradigms in nutrient metal homeostasis at the pathogen-host interface.
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