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Majdi C, Meffre P, Benfodda Z. Recent advances in the development of bacterial response regulators inhibitors as antibacterial and/or antibiotic adjuvant agent: A new approach to combat bacterial resistance. Bioorg Chem 2024; 150:107606. [PMID: 38968903 DOI: 10.1016/j.bioorg.2024.107606] [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: 03/25/2024] [Revised: 06/21/2024] [Accepted: 06/28/2024] [Indexed: 07/07/2024]
Abstract
The number of new antibacterial agents currently being discovered is insufficient to combat bacterial resistance. It is extremely challenging to find new antibiotics and to introduce them to the pharmaceutical market. Therefore, special attention must be given to find new strategies to combat bacterial resistance and prevent bacteria from developing resistance. Two-component system is a transduction system and the most prevalent mechanism employed by bacteria to respond to environmental changes. This signaling system consists of a membrane sensor histidine kinase that perceives environmental stimuli and a response regulator which acts as a transcription factor. The approach consisting of developing response regulators inhibitors with antibacterial activity or antibiotic adjuvant activity is a novel approach that has never been previously reviewed. In this review we report for the first time, the importance of targeting response regulators and summarizing all existing studies carried out from 2008 until now on response regulators inhibitors as antibacterial agents or / and antibiotic adjuvants. Moreover, we describe the antibacterial activity and/or antibiotic adjuvants activity against the studied bacterial strains and the mechanism of different response regulator inhibitors when it's possible.
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2
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Espinasse A, Goswami M, Yang J, Vorasin O, Ji Y, Carlson EE. Targeting multidrug resistant Staphylococcus infections with bacterial histidine kinase inhibitors. Chem Sci 2023; 14:5028-5037. [PMID: 37206395 PMCID: PMC10189854 DOI: 10.1039/d2sc05369a] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 04/10/2023] [Indexed: 05/21/2023] Open
Abstract
The emergence of drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), which are not susceptible to current antibiotics has necessitated the development of novel approaches and targets to tackle this growing challenge. Bacterial two-component systems (TCSs) play a central role in the adaptative response of bacteria to their ever-changing environment. They are linked to antibiotic resistance and bacterial virulence making the proteins of the TCSs, histidine kinases and response regulators, attractive for the development of novel antibacterial drugs. Here, we developed a suite of maleimide-based compounds that we evaluated against a model histidine kinase, HK853, in vitro and in silico. The most potent leads were then assessed for their ability to decrease the pathogenicity and virulence of MRSA, resulting in the identification of a molecule that decreased the lesion size caused by a methicillin-resistant S. aureus skin infection by 65% in a murine model.
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Affiliation(s)
- Adeline Espinasse
- Department of Chemistry, University of Minnesota 225 Pleasant St. SE Minneapolis 55454 MN USA
| | - Manibarsha Goswami
- Department of Chemistry, University of Minnesota 225 Pleasant St. SE Minneapolis 55454 MN USA
| | - Junshu Yang
- Department of Veterinary and Biomedical Sciences, University of Minnesota 1971 Commonwealth Ave Falcon Heights 55108 MN USA
| | - Onanong Vorasin
- Department of Chemistry, University of Minnesota 225 Pleasant St. SE Minneapolis 55454 MN USA
- Department of Chemistry, Faculty of Science, Mahidol University Rama 6 Road Bangkok 10400 Thailand
| | - Yinduo Ji
- Department of Veterinary and Biomedical Sciences, University of Minnesota 1971 Commonwealth Ave Falcon Heights 55108 MN USA
| | - Erin E Carlson
- Department of Chemistry, University of Minnesota 225 Pleasant St. SE Minneapolis 55454 MN USA
- Department of Medicinal Chemistry, University of Minnesota 208 Harvard Street SE Minneapolis 55454 Minnesota USA
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota 321 Church St SE Minneapolis 55454 Minnesota USA
- Department of Pharmacology, University of Minnesota 321 Church St SE Minneapolis 55454 Minnesota USA
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3
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Chen H, Yu C, Wu H, Li G, Li C, Hong W, Yang X, Wang H, You X. Recent Advances in Histidine Kinase-Targeted Antimicrobial Agents. Front Chem 2022; 10:866392. [PMID: 35860627 PMCID: PMC9289397 DOI: 10.3389/fchem.2022.866392] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/16/2022] [Indexed: 11/15/2022] Open
Abstract
The prevalence of antimicrobial-resistant pathogens significantly limited the number of effective antibiotics available clinically, which urgently requires new drug targets to screen, design, and develop novel antibacterial drugs. Two-component system (TCS), which is comprised of a histidine kinase (HK) and a response regulator (RR), is a common mechanism whereby bacteria can sense a range of stimuli and make an appropriate adaptive response. HKs as the sensor part of the bacterial TCS can regulate various processes such as growth, vitality, antibiotic resistance, and virulence, and have been considered as a promising target for antibacterial drugs. In the current review, we highlighted the structural basis and functional importance of bacterial TCS especially HKs as a target in the discovery of new antimicrobials, and summarize the latest research progress of small-molecule HK-inhibitors as potential novel antimicrobial drugs reported in the past decade.
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Affiliation(s)
- Hongtong Chen
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chengqi Yu
- School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Han Wu
- School of Pharmacy, Minzu University of China, Beijing, China
- Key Laboratory of Ethnomedicine (Minzu University of China), Ministry of Education, Beijing, China
| | - Guoqing Li
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Congran Li
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Hong
- Beijing Institute of Collaborative Innovation, Beijing, China
| | - Xinyi Yang
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hao Wang
- School of Pharmacy, Minzu University of China, Beijing, China
- Key Laboratory of Ethnomedicine (Minzu University of China), Ministry of Education, Beijing, China
- Institute of National Security, Minzu University of China, Beijing, China
| | - Xuefu You
- Laboratory of Pharmacology/Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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4
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Bertram R, Neumann B, Schuster CF. Status quo of tet regulation in bacteria. Microb Biotechnol 2022; 15:1101-1119. [PMID: 34713957 PMCID: PMC8966031 DOI: 10.1111/1751-7915.13926] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/02/2021] [Accepted: 09/04/2021] [Indexed: 11/27/2022] Open
Abstract
The tetracycline repressor (TetR) belongs to the most popular, versatile and efficient transcriptional regulators used in bacterial genetics. In the tetracycline (Tc) resistance determinant tet(B) of transposon Tn10, tetR regulates the expression of a divergently oriented tetA gene that encodes a Tc antiporter. These components of Tn10 and of other natural or synthetic origins have been used for tetracycline-dependent gene regulation (tet regulation) in at least 40 bacterial genera. Tet regulation serves several purposes such as conditional complementation, depletion of essential genes, modulation of artificial genetic networks, protein overexpression or the control of gene expression within cell culture or animal infection models. Adaptations of the promoters employed have increased tet regulation efficiency and have made this system accessible to taxonomically distant bacteria. Variations of TetR, different effector molecules and mutated DNA binding sites have enabled new modes of gene expression control. This article provides a current overview of tet regulation in bacteria.
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Affiliation(s)
- Ralph Bertram
- Institute of Clinical Hygiene, Medical Microbiology and InfectiologyParacelsus Medical UniversityProf.‐Ernst‐Nathan‐Straße 1Nuremberg90419Germany
| | - Bernd Neumann
- Institute of Clinical Hygiene, Medical Microbiology and InfectiologyParacelsus Medical UniversityProf.‐Ernst‐Nathan‐Straße 1Nuremberg90419Germany
| | - Christopher F. Schuster
- Department of Infectious DiseasesDivision of Nosocomial Pathogens and Antibiotic ResistancesRobert Koch InstituteBurgstraße 37Wernigerode38855Germany
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5
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Párraga Solórzano PK, Shupe AC, Kehl-Fie TE. The Sensor Histidine Kinase ArlS Is Necessary for Staphylococcus aureus To Activate ArlR in Response to Nutrient Availability. J Bacteriol 2021; 203:e0042221. [PMID: 34606376 PMCID: PMC8604075 DOI: 10.1128/jb.00422-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 09/25/2021] [Indexed: 12/12/2022] Open
Abstract
Staphylococcus aureus is a versatile opportunistic pathogen whose success is driven by its ability to adapt to diverse environments and host-imposed stresses. Two-component signal transduction systems, such as ArlRS, often mediate these adaptations. Loss of ArlRS or the response regulator ArlR alone impairs the ability of S. aureus to respond to host-imposed manganese starvation and glucose limitation. As sensor histidine kinases and response regulators frequently work as pairs, it has been assumed that ArlS senses and activates ArlR in response to these stimuli. However, recent work suggests that the sensor histidine kinase GraS can also activate ArlR, calling the contribution of ArlS in responding to manganese and glucose availability into question. The results of current studies reveal that ArlS is necessary to activate ArlR in response to manganese sequestration by the host immune effector calprotectin and glucose limitation. Although the loss of ArlS does not completely eliminate ArlR activity, this response regulator is no longer responsive to manganese or glucose availability in the absence of its cognate histidine kinase. Despite the residual activity of ArlR in the absence of ArlS, ArlR phosphorylation by ArlS is required for S. aureus to resist calprotectin-imposed metal starvation. Cumulatively, these findings contribute to the understanding of S. aureus signal transduction in response to nutritional immunity and support the previous observation indicating that ArlRS is activated by a common signal derived from host-imposed manganese and glucose limitation. IMPORTANCE The ability of pathogens, including Staphylococcus aureus, to sense and adapt to diverse environments partially relies on two-component systems, such as ArlRS. Recent work revealed that the response regulator ArlR can be cross-activated by the sensor histidine kinase GraS, rendering the role of its cognate partner, ArlS, in response to manganese and glucose limitation uncertain. The results of this study reveal that ArlS is necessary for the activation of ArlR in response to calprotectin and glucose limitation. Although a low level of ArlR activity remains in the absence of ArlS, ArlS phosphotransfer to ArlR is required for S. aureus to overcome calprotectin-induced nutritional stress. Collectively, this study provides fundamental information to understand how ArlRS mediates staphylococcal adaptation during infection.
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Affiliation(s)
| | - Angela C. Shupe
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Thomas E. Kehl-Fie
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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6
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Identification of cbiO Gene Critical for Biofilm Formation by MRSA CFSa36 Strain Isolated from Pediatric Patient with Cystic Fibrosis. Pathogens 2021; 10:pathogens10111363. [PMID: 34832519 PMCID: PMC8622116 DOI: 10.3390/pathogens10111363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 10/18/2021] [Accepted: 10/19/2021] [Indexed: 11/23/2022] Open
Abstract
The colonization of Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), has a detrimental effect on the respiratory care of pediatric patients with cystic fibrosis (CF). In addition to being resistant to multiple antibiotics, S. aureus also has the ability to form biofilms, which makes the infection more difficult to treat and eradicate. In this study, we examined the ability of S. aureus strains isolated from pediatric patients with CF to form biofilms. We screened a transposon mutant library of MRSA and identified a putative cobalt transporter ATP binding domain (cbiO) that is required for biofilm formation. We discovered that deleting cbiO creating a cbiO null mutant in CFSa36 (an MRSA strain isolated from a patient with cystic fibrosis) significantly hinders the ability of CFSa36 to form biofilm. The complementation of cbiO restored the ability of the cbiO deletion mutant to generate biofilm. Interestingly, we revealed that incorporating extra copper ions to the chemically defined medium (CDM) complemented the function of cbiO for biofilm formation in a dose-dependent manner, while the addition of extra iron ions in CDM enhanced the effect of cbiO null mutation on biofilm formation. In addition, neither the addition of certain extra amounts of copper ions nor iron ions in CDM had an impact on bacterial growth. Taken together, our findings suggest that cbiO mediates biofilm formation by affecting the transportation of copper ions in the MRSA CFSa36 strain. This study provides new insights into the molecular basis of biofilm formation by S. aureus.
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7
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Carbon Source-Dependent Reprogramming of Anaerobic Metabolism in Staphylococcus aureus. J Bacteriol 2021; 203:JB.00639-20. [PMID: 33526614 DOI: 10.1128/jb.00639-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/28/2021] [Indexed: 11/20/2022] Open
Abstract
To be a successful pathogen, Staphylococcus aureus has to adapt its metabolism to the typically oxygen- and glucose-limited environment of the host. Under fermenting conditions and in the presence of glucose, S. aureus uses glycolysis to generate ATP via substrate-level phosphorylation and mainly lactic acid fermentation to maintain the redox balance by reoxidation of NADH equivalents. However, it is less clear how S. aureus proceeds under anoxic conditions and glucose limitation, likely representing the bona fide situation in the host. Using a combination of proteomic, transcriptional, and metabolomic analyses, we show that in the absence of an abundant glycolysis substrate, the available carbon source pyruvate is converted to acetyl coenzyme A (AcCoA) in a pyruvate formate-lyase (PflB)-dependent reaction to produce ATP and acetate. This process critically depends on derepression of the catabolite control protein A (CcpA), leading to upregulation of pflB transcription. Under these conditions, ethanol production is repressed to prevent wasteful consumption of AcCoA. In addition, our global and quantitative characterization of the metabolic switch prioritizing acetate over lactate fermentation when glucose is absent illustrates examples of carbon source-dependent control of colonization and pathogenicity factors.IMPORTANCE Under infection conditions, S. aureus needs to ensure survival when energy production via oxidative phosphorylation is not possible, e.g., either due to the lack of terminal electron acceptors or by the inactivation of components of the respiratory chain. Under these conditions, S. aureus can switch to mixed-acid fermentation to sustain ATP production by substrate level phosphorylation. The drop in the cellular NAD+/NADH ratio is sensed by the repressor Rex, resulting in derepression of fermentation genes. Here, we show that expression of fermentation pathways is further controlled by CcpA in response to the availability of glucose to ensure optimal resource utilization under growth-limiting conditions. We provide evidence for carbon source-dependent control of colonization and virulence factors. These findings add another level to the regulatory network controlling mixed-acid fermentation in S. aureus and provide additional evidence for the lifestyle-modulating effect of carbon sources available to S. aureus.
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8
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Wu S, Lin K, Liu Y, Zhang H, Lei L. Two-component signaling pathways modulate drug resistance of Staphylococcus aureus (Review). Biomed Rep 2020; 13:5. [PMID: 32607234 PMCID: PMC7323452 DOI: 10.3892/br.2020.1312] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 05/07/2020] [Indexed: 02/05/2023] Open
Abstract
As the issues surrounding antibiotic-resistant strains of Staphylococcus aureus (S. aureus) are becoming increasingly serious concerns, it is imperative to investigate new therapeutic targets to successfully treat patients with S. aureus infections. The two-component signal transduction system is one of the primary pathways by which bacteria adapt to the external environment, and it serves an important role in regulating virulence gene expression, cell wall synthesis, biofilm formation and bacterial activity. There are 17 two-component signaling pathways in S. aureus, among which WalKR/VicSR/YycGF, AirSR/YhcSR, vancomycin resistance associated regulator/sensor and LytRS have been demonstrated to serve vital roles in regulating bacterial resistance, and are hypothesized to be potential targets for the treatment of S. aureus infections. The present review assesses the mechanism of the two-component signaling pathways associated with the development of S. aureus resistance.
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Affiliation(s)
- Shizhou Wu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China.,State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Kaifeng Lin
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Yunjie Liu
- West China School of Public Health, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Hui Zhang
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Lei Lei
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China
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9
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Klein R, Kretzschmar A, Unden G. Control of the bifunctional O
2
‐sensor kinase NreB of
Staphylococcus carnosus
by the nitrate sensor NreA: Switching from kinase to phosphatase state. Mol Microbiol 2019; 113:369-380. [DOI: 10.1111/mmi.14425] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Robin Klein
- Microbiology and Wine Research, Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Germany
| | - Ann‐Katrin Kretzschmar
- Microbiology and Wine Research, Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Germany
| | - Gottfried Unden
- Microbiology and Wine Research, Institute for Molecular Physiology Johannes Gutenberg‐University Mainz Germany
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10
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Párraga Solórzano PK, Yao J, Rock CO, Kehl-Fie TE. Disruption of Glycolysis by Nutritional Immunity Activates a Two-Component System That Coordinates a Metabolic and Antihost Response by Staphylococcus aureus. mBio 2019; 10:e01321-19. [PMID: 31387906 PMCID: PMC6686040 DOI: 10.1128/mbio.01321-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/09/2019] [Indexed: 02/01/2023] Open
Abstract
During infection, bacteria use two-component signal transduction systems to sense and adapt to the dynamic host environment. Despite critically contributing to infection, the activating signals of most of these regulators remain unknown. This also applies to the Staphylococcus aureus ArlRS two-component system, which contributes to virulence by coordinating the production of toxins, adhesins, and a metabolic response that enables the bacterium to overcome host-imposed manganese starvation. Restricting the availability of essential transition metals, a strategy known as nutritional immunity, constitutes a critical defense against infection. In this work, expression analysis revealed that manganese starvation imposed by the immune effector calprotectin or by the absence of glycolytic substrates activates ArlRS. Manganese starvation imposed by calprotectin also activated the ArlRS system even when glycolytic substrates were present. A combination of metabolomics, mutational analysis, and metabolic feeding experiments revealed that ArlRS is activated by alterations in metabolic flux occurring in the latter half of the glycolytic pathway. Moreover, calprotectin was found to induce expression of staphylococcal leukocidins in an ArlRS-dependent manner. These studies indicated that ArlRS is a metabolic sensor that allows S. aureus to integrate multiple environmental stresses that alter glycolytic flux to coordinate an antihost response and to adapt to manganese starvation. They also established that the latter half of glycolysis represents a checkpoint to monitor metabolic state in S. aureus Altogether, these findings contribute to understanding how invading pathogens, such as S. aureus, adapt to the host during infection and suggest the existence of similar mechanisms in other bacterial species.IMPORTANCE Two-component regulatory systems enable bacteria to adapt to changes in their environment during infection by altering gene expression and coordinating antihost responses. Despite the critical role of two-component systems in bacterial survival and pathogenesis, the activating signals for most of these regulators remain unidentified. This is exemplified by ArlRS, a Staphylococcus aureus global regulator that contributes to virulence and to resisting host-mediated restriction of essential nutrients, such as manganese. In this report, we demonstrate that manganese starvation and the absence of glycolytic substrates activate ArlRS. Further investigations revealed that ArlRS is activated when the latter half of glycolysis is disrupted, suggesting that S. aureus monitors flux through the second half of this pathway. Host-imposed manganese starvation also induced the expression of pore-forming toxins in an ArlRS-dependent manner. Cumulatively, this work reveals that ArlRS acts as a sensor that links nutritional status, cellular metabolism, and virulence regulation.
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Affiliation(s)
- Paola K Párraga Solórzano
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Departmento de Ciencias de la Vida, Universidad de las Fuerzas Armadas ESPE, Sangolquí, Ecuador
| | - Jiangwei Yao
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Charles O Rock
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, USA
| | - Thomas E Kehl-Fie
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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11
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Casabona MG, Buchanan G, Zoltner M, Harkins CP, Holden MTG, Palmer T. Functional analysis of the EsaB component of the Staphylococcus aureus Type VII secretion system. MICROBIOLOGY-SGM 2017; 163:1851-1863. [PMID: 29165232 PMCID: PMC5845737 DOI: 10.1099/mic.0.000580] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Type VII secretion systems (T7SS) are found in many bacteria and secrete proteins involved in virulence and bacterial competition. In Staphylococcus aureus the small ubiquitin-like EsaB protein has been previously implicated as having a regulatory role in the production of the EsxC substrate. Here we show that in the S. aureus RN6390 strain, EsaB does not genetically regulate production of any T7 substrates or components, but is indispensable for secretion activity. Consistent with EsaB being an essential component of the T7SS, loss of either EsaB or EssC are associated with upregulation of a common set of iron acquisition genes. However, a further subset of genes were dysregulated only in the absence of EsaB. Quantitative western blotting indicates that EsaB is present at very low levels in cells. Substitution of a highly conserved threonine for alanine or arginine resulted in a loss of EsaB activity and destabilisation of the protein. Taken together our findings show that EsaB is essential for T7SS activity in RN6390.
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Affiliation(s)
- M Guillermina Casabona
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | - Grant Buchanan
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | - Martin Zoltner
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
| | | | | | - Tracy Palmer
- Division of Molecular Microbiology School of Life Sciences, University of Dundee, Dundee, UK
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12
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Balasubramanian D, Harper L, Shopsin B, Torres VJ. Staphylococcus aureus pathogenesis in diverse host environments. Pathog Dis 2017; 75:ftx005. [PMID: 28104617 DOI: 10.1093/femspd/ftx005] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/18/2017] [Indexed: 12/21/2022] Open
Abstract
Staphylococcus aureus is an eminent human pathogen that can colonize the human host and cause severe life-threatening illnesses. This bacterium can reside in and infect a wide range of host tissues, ranging from superficial surfaces like the skin to deeper tissues such as in the gastrointestinal tract, heart and bones. Due to its multifaceted lifestyle, S. aureus uses complex regulatory networks to sense diverse signals that enable it to adapt to different environments and modulate virulence. In this minireview, we explore well-characterized environmental and host cues that S. aureus responds to and describe how this pathogen modulates virulence in response to these signals. Lastly, we highlight therapeutic approaches undertaken by several groups to inhibit both signaling and the cognate regulators that sense and transmit these signals downstream.
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Affiliation(s)
- Divya Balasubramanian
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Lamia Harper
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
| | - Bo Shopsin
- Department of Medicine, Division of Infectious Diseases, New York University School of Medicine, New York, NY 10016 USA
| | - Victor J Torres
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA
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13
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Cardona ST, Choy M, Hogan AM. Essential Two-Component Systems Regulating Cell Envelope Functions: Opportunities for Novel Antibiotic Therapies. J Membr Biol 2017; 251:75-89. [DOI: 10.1007/s00232-017-9995-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 10/20/2017] [Indexed: 01/22/2023]
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14
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Tanner AW, Carabetta VJ, Martinie RJ, Mashruwala AA, Boyd JM, Krebs C, Dubnau D. The RicAFT (YmcA-YlbF-YaaT) complex carries two [4Fe-4S] 2+ clusters and may respond to redox changes. Mol Microbiol 2017; 104:837-850. [PMID: 28295778 DOI: 10.1111/mmi.13667] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2017] [Indexed: 01/10/2023]
Abstract
During times of environmental insult, Bacillus subtilis undergoes developmental changes leading to biofilm formation, sporulation and competence. Each of these states is regulated in part by the phosphorylated form of the master response regulator Spo0A (Spo0A∼P). The phosphorylation state of Spo0A is controlled by a multi-component phosphorelay. RicA, RicF and RicT (previously YmcA, YlbF and YaaT) have been shown to be important regulatory proteins for multiple developmental fates. These proteins directly interact and form a stable complex, which has been proposed to accelerate the phosphorelay. Indeed, this complex is sufficient to stimulate the rate of phosphotransfer amongst the phosphorelay proteins in vitro. In this study, we demonstrate that two [4Fe-4S]2+ clusters can be assembled on the complex. As with other iron-sulfur cluster-binding proteins, the complex was also found to bind FAD, hinting that these cofactors may be involved in sensing the cellular redox state. This work provides the first comprehensive characterization of an iron-sulfur protein complex that regulates Spo0A∼P levels. Phylogenetic and genetic evidence suggests that the complex plays a broader role beyond stimulation of the phosphorelay.
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Affiliation(s)
- Andrew W Tanner
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Valerie J Carabetta
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.,Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Ryan J Martinie
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ameya A Mashruwala
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Jeffrey M Boyd
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA.,Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - David Dubnau
- Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.,Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
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The Staphylococcus aureus AirSR Two-Component System Mediates Reactive Oxygen Species Resistance via Transcriptional Regulation of Staphyloxanthin Production. Infect Immun 2017; 85:IAI.00838-16. [PMID: 27872240 DOI: 10.1128/iai.00838-16] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 11/18/2016] [Indexed: 01/22/2023] Open
Abstract
Staphylococcus aureus is an important opportunistic pathogen and is the etiological agent of many hospital- and community-acquired infections. The golden pigment, staphyloxanthin, of S. aureus colonies distinguishes it from other staphylococci and related Gram-positive cocci. Staphyloxanthin is the product of a series of biosynthetic steps that produce a unique membrane-embedded C30 golden carotenoid and is an important antioxidant. We observed that a strain with an inducible airR overexpression cassette had noticeably increased staphyloxanthin production compared to the wild-type strain under aerobic culturing conditions. Further analysis revealed that depletion or overproduction of the AirR response regulator resulted in a corresponding decrease or increase in staphyloxanthin production and susceptibility to killing by hydrogen peroxide, respectively. Furthermore, the genetic elimination of staphyloxanthin during AirR overproduction abolished the protective phenotype of increased staphyloxanthin production in a whole-blood survival assay. Promoter reporter and gel shift assays determined that the AirR response regulator is a direct positive regulator of the staphyloxanthin-biosynthetic operon, crtOPQMN, but is epistatic to alternative sigma factor B. Taken together, these data indicate that AirSR positively regulates the staphyloxanthin-biosynthetic operon crtOPQMN, promoting survival of S. aureus in the presence of oxidants.
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Hall JW, Yang J, Guo H, Ji Y. The AirSR two-component system contributes to Staphylococcus aureus survival in human blood and transcriptionally regulates sspABC operon. Front Microbiol 2015; 6:682. [PMID: 26191060 PMCID: PMC4490255 DOI: 10.3389/fmicb.2015.00682] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022] Open
Abstract
To date, genes identified and transcriptionally regulated by the AirSR TCS have been involved in energy production and cellular homeostasis of the staphylococcal cell. It is well accepted that the state of cellular metabolism impacts the expression of virulence factors in Staphylococcus aureus. For this reason, we conducted experiments to determine if the AirSR TCS contributes to the pathogenesis of S. aureus using an antisense RNA interference technology, an inducible overexpression system, and gene deletions. Depletion of AirSR by antisense RNA expression or deletion of the genes, results in significant decrease in bacterial survival in human blood. Conversely, overexpression of AirR significantly promotes survival of S. aureus in blood. AirR promotes the secretion of virulence factors that inhibits opsonin-based phagocytosis. This enhanced survival is partially linked to the transcriptional regulation of the sspABC operon, encoding V8 protease (SspA), staphopain B (SspB) and staphostatin B (SspC). SspA and SspB are known virulence factors which proteolytically digest opsonins and inhibit killing of S. aureus by professional phagocytes. This is the first evidence linking the AirSR TCS to pathogenesis of S. aureus.
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Affiliation(s)
- Jeffrey W Hall
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN USA
| | - Junshu Yang
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN USA
| | - Haiyong Guo
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN USA
| | - Yinduo Ji
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN USA
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Yang J, Liang X, Ji Y. The novel transcriptional regulator SA1804 Is involved in mediating the invasion and cytotoxicity of Staphylococcus aureus. Front Microbiol 2015; 6:174. [PMID: 25806024 PMCID: PMC4353350 DOI: 10.3389/fmicb.2015.00174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 02/16/2015] [Indexed: 11/24/2022] Open
Abstract
The two-component regulatory system, SaeRS, controls expression of important virulence factors, including toxins and invasins, which contribute to the pathogenicity of Staphylococcus aureus. Previously, we conducted a transcriptomics study for identification of SaeRS regulon and found that inactivation of SaeRS dramatically enhances the transcription of a novel transcriptional regulator (SA1804). This led us to question whether SA1804 is involved in bacterial pathogenicity by regulating the expression of virulence factors. To address this question, we created sa1804, saeRS, and sa1804/saeRS double deletion mutants in a USA300 community-acquired MRSA strain, 923, and determined their impact on the pathogenicity. The deletion of sa1804 dramatically increased the cytotoxicity and enhanced the capacity of bacteria to invade into the epithelial cells (A549), whereas the deletion of saeRS eliminated the cytotoxicity and abolished the bacterial ability to invade into the epithelial cells. Moreover, the double deletions of sa1804 and saeRS appeared a similar phenotype with the saeRS null mutation. Furthermore, we determined the regulatory mechanism of SA1804 using qPCR and gel-shift approaches. Our data indicate that the novel virulence repressor SA1804 is dependent on the regulation of SaeRS. This study sheds light on the regulatory mechanism of virulence factors and allows for us further elucidate the molecular pathogenesis of S. aureus.
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Affiliation(s)
- Junshu Yang
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota Saint Paul, MN, USA
| | - Xudong Liang
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota Saint Paul, MN, USA
| | - Yinduo Ji
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota Saint Paul, MN, USA
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18
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The Role of Two-Component Signal Transduction Systems in Staphylococcus aureus Virulence Regulation. Curr Top Microbiol Immunol 2015; 409:145-198. [PMID: 26728068 DOI: 10.1007/82_2015_5019] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Staphylococcus aureus is a versatile, opportunistic human pathogen that can asymptomatically colonize a human host but can also cause a variety of cutaneous and systemic infections. The ability of S. aureus to adapt to such diverse environments is reflected in the presence of complex regulatory networks fine-tuning metabolic and virulence gene expression. One of the most widely distributed mechanisms is the two-component signal transduction system (TCS) which allows a pathogen to alter its gene expression profile in response to environmental stimuli. The simpler TCSs consist of only a transmembrane histidine kinase (HK) and a cytosolic response regulator. S. aureus encodes a total of 16 conserved pairs of TCSs that are involved in diverse signalling cascades ranging from global virulence gene regulation (e.g. quorum sensing by the Agr system), the bacterial response to antimicrobial agents, cell wall metabolism, respiration and nutrient sensing. These regulatory circuits are often interconnected and affect each other's expression, thus fine-tuning staphylococcal gene regulation. This manuscript gives an overview of the current knowledge of staphylococcal environmental sensing by TCS and its influence on virulence gene expression and virulence itself. Understanding bacterial gene regulation by TCS can give major insights into staphylococcal pathogenicity and has important implications for knowledge-based drug design and vaccine formulation.
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Mettert EL, Kiley PJ. Fe-S proteins that regulate gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:1284-93. [PMID: 25450978 DOI: 10.1016/j.bbamcr.2014.11.018] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/24/2014] [Accepted: 11/13/2014] [Indexed: 02/06/2023]
Abstract
Iron-sulfur (Fe-S) cluster containing proteins that regulate gene expression are present in most organisms. The innate chemistry of their Fe-S cofactors makes these regulatory proteins ideal for sensing environmental signals, such as gases (e.g. O2 and NO), levels of Fe and Fe-S clusters, reactive oxygen species, and redox cycling compounds, to subsequently mediate an adaptive response. Here we review the recent findings that have provided invaluable insight into the mechanism and function of these highly significant Fe-S regulatory proteins. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.
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Affiliation(s)
- Erin L Mettert
- University of Wisconsin-Madison, Department of Biomolecular Chemistry, 440 Henry Mall, Biochemical Sciences Building, Room 4204C, Madison, WI 53706, USA.
| | - Patricia J Kiley
- University of Wisconsin-Madison, Department of Biomolecular Chemistry, 440 Henry Mall, Biochemical Sciences Building, Room 4204C, Madison, WI 53706, USA.
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Sun H, Yang Y, Xue T, Sun B. Modulation of cell wall synthesis and susceptibility to vancomycin by the two-component system AirSR in Staphylococcus aureus NCTC8325. BMC Microbiol 2013; 13:286. [PMID: 24320748 PMCID: PMC4029521 DOI: 10.1186/1471-2180-13-286] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 12/04/2013] [Indexed: 11/30/2022] Open
Abstract
Background Vancomycin has been the medication of last resort to cure infections caused by Staphylococcus aureus since the increase in the prevalence of methicillin-resistant Staphylococcus aureus (MRSA). Some strains have developed vancomycin-intermediate resistance, which is generally associated with altered expression of or mutations in some part of the two-component system (TCS), such as GraSR, VraSR, and WalKR. Results We deleted the AirSR TCS in S. aureus NCTC8325 and compared the resultant transcript levels with those of its parent strain using microarray analysis. The results indicated that more than 20 genes that are related to cell wall metabolism were down-regulated in the airSR mutant. The airSR mutant exhibited reduced autolysis rates and reduced viability in the presence of vancomycin. Real-time reverse transcription PCR and DNA mobility shift assays verified that AirR can directly bind to and regulate genes that function in cell wall metabolism (cap, pbp1, and ddl) and autolysis (lytM). Conclusions AirSR acts as a positive regulator in cell wall biosynthesis and turnover in Staphylococcus aureus NCTC8325.
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Affiliation(s)
| | | | - Ting Xue
- Department of Microbiology and Immunology, School of Life Sciences, University of Science and Technology of China, Huangshan Road, Hefei, Anhui 230027, China.
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Njoroge JW, Sperandio V. Interference with Bacterial Cell-to-Cell Chemical Signaling in Development of New Anti-Infectives. Antibiotics (Basel) 2013. [DOI: 10.1002/9783527659685.ch10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Ji Y, Lei T. Antisense RNA regulation and application in the development of novel antibiotics to combat multidrug resistant bacteria. Sci Prog 2013; 96:43-60. [PMID: 23738437 PMCID: PMC10365521 DOI: 10.3184/003685013x13617194309028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Despite the availability of antibiotics and vaccines, infectious diseases remain one of most dangerous threats to humans and animals. The overuse and misuse of antibacterial agents have led to the emergence of multidrug resistant bacterial pathogens. Bacterial cells are often resilient enough to survive in even the most extreme environments. To do so, the organisms have evolved different mechanisms, including a variety of two-component signal transduction systems, which allow the bacteria to sense the surrounding environment and regulate gene expression in order to adapt and respond to environmental stimuli. In addition, some bacteria evolve resistance to antibacterial agents while many bacterial cells are able to acquire resistance genes from other bacterial species to enable them to survive in the presence of toxic antimicrobial agents. The crisis of antimicrobial resistance is an unremitting menace to human health and a burden on public health. The rapid increase in antimicrobial resistant organisms and limited options for development of new classes of antibiotics heighten the urgent need to develop novel potent antibacterial therapeutics in order to combat multidrug resistant infections. In this review, we introduce the regulatory mechanisms of antisense RNA and significant applications of regulated antisense RNA interference technology in early drug discovery. This includes the identification and evaluation of drug targets in vitro and in vivo, the determination of mode of action for antibiotics and new antibacterial agents, as well as the development of peptide-nucleic acid conjugates as novel antibacterials.
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Hall JW, Ji Y. Sensing and Adapting to Anaerobic Conditions by Staphylococcus aureus. ADVANCES IN APPLIED MICROBIOLOGY 2013; 84:1-25. [PMID: 23763757 DOI: 10.1016/b978-0-12-407673-0.00001-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A highly adaptive commensal organism, Staphylococcus aureus, possesses an array of genes that allow the bacterium to survive and grow in a wide variety of niches. Several of these niches are known to be or become anaerobic during the course of an infection; additionally, biofilms that develop, commonly on implanted medical devices, become anaerobic. The metabolic capability of S. aureus provides the organism with the essential nutrients needed to continue to grow, divide, and thwart the host immune system in the presence or absence of oxygen. In order to utilize the ATP-producing pathways and maintain cellular health S. aureus has evolved a series of regulatory systems that regulate these ATP-producing pathways. In this review, we discuss the protein signaling systems that sense, indirectly and directly, anaerobic conditions, their sensory mechanisms and signals, and outline the genes that are altered due to the absence of oxygen and the subsequent response by the bacterial cell. The switch from aerobic to anaerobic growth in S. aureus is complex and highly regulated, with some metabolic pathways regulated by multiple regulatory systems to ensure maximal utilization of each pathway and substrate.
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Affiliation(s)
- Jeffrey W Hall
- Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, St. Paul, Minneapolis, Minnesota, USA
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24
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The essential yhcSR two-component signal transduction system directly regulates the lac and opuCABCD operons of Staphylococcus aureus. PLoS One 2012; 7:e50608. [PMID: 23226327 PMCID: PMC3511567 DOI: 10.1371/journal.pone.0050608] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/26/2012] [Indexed: 01/27/2023] Open
Abstract
Our previous studies suggested that the essential two-component signal transduction system, YhcSR, regulates the opuCABCD operon at the transcriptional level, and the Pspac-driven opuCABCD partially complements the lethal effects of yhcS antisense RNA expression in Staphylococcus aureus. However, the reason why yhcSR regulon is required for growth is still unclear. In this report, we present that the lac and opuC operons are directly transcriptionally regulated by YhcSR. Using real-time RT-PCR we showed that the down-regulation of yhcSR expression affected the transcription of lacA encoding galactose-6-phosphotase isomerase subunit LacA, and opuCA encoding a subunit of a glycine betaine/carnitine/choline ABC transporter. Promoter-lux reporter fusion studies further confirmed the transcriptional regulation of lac by YhcSR. Gel shift assays revealed that YhcR binds to the promoter regions of the lac and opuC operons. Moreover, the Pspac-driven lacABC expression in trans was able to partially complement the lethal effect of induced yhcS antisense RNA. Likewise, the Pspac-driven opuCABCD expression in trans complemented the growth defect of S. aureus in a high osmotic strength medium during the depletion of YhcSR. Taken together, the above data indicate that the yhcSR system directly regulates the expression of lac and opuC operons, which, in turn, may be partially associated with the essentiality of yhcSR in S. aureus. These results provide a new insight into the biological functions of the yhcSR, a global regulator.
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Jeong DW, Cho H, Jones MB, Shatzkes K, Sun F, Ji Q, Liu Q, Peterson SN, He C, Bae T. The auxiliary protein complex SaePQ activates the phosphatase activity of sensor kinase SaeS in the SaeRS two-component system of Staphylococcus aureus. Mol Microbiol 2012; 86:331-48. [PMID: 22882143 DOI: 10.1111/j.1365-2958.2012.08198.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2012] [Indexed: 12/21/2022]
Abstract
In bacterial two-component regulatory systems (TCSs), dephosphorylation of phosphorylated response regulators is essential for resetting the activated systems to the pre-activation state. However, in the SaeRS TCS, a major virulence TCS of Staphylococcus aureus, the mechanism for dephosphorylation of the response regulator SaeR has not been identified. Here we report that two auxiliary proteins from the sae operon, SaeP and SaeQ, form a protein complex with the sensor kinase SaeS and activate the sensor kinase's phosphatase activity. Efficient activation of the phosphatase activity required the presence of both SaeP and SaeQ. When SaeP and SaeQ were ectopically expressed, the expression of coagulase, a sae target with low affinity for phosphorylated SaeR, was greatly reduced, while the expression of alpha-haemolysin, a sae target with high affinity for phosphorylated SaeR, was not, demonstrating a differential effect of SaePQ on sae target gene expression. When expression of SaePQ was abolished, most sae target genes were induced at an elevated level. Since the expression of SaeP and SaeQ is induced by the SaeRS TCS, these results suggest that the SaeRS TCS returns to the pre-activation state by a negative feedback mechanism.
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Affiliation(s)
- Do-Won Jeong
- Department of Microbiology and Immunology, Indiana University School of Medicine-Northwest, Gary, IN 46408, USA
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