1
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Reslane I, Handke LD, Watson GF, Shinde D, Ahn JS, Endres JL, Razvi F, Gilbert EA, Bayles KW, Thomas VC, Lehman MK, Fey PD. Glutamate -dependent arginine biosynthesis requires the inactivation of spoVG, sarA, and ahrC in Staphylococcus aureus. J Bacteriol 2024; 206:e0033723. [PMID: 38299858 PMCID: PMC10883023 DOI: 10.1128/jb.00337-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/09/2024] [Indexed: 02/02/2024] Open
Abstract
Genome sequencing has demonstrated that Staphylococcus aureus encodes arginine biosynthetic genes argDCJBFGH synthesizing proteins that mediate arginine biosynthesis using glutamate as a substrate. Paradoxically, however, S. aureus does not grow in a defined, glutamate-replete medium lacking arginine and glucose (CDM-R). Studies from our laboratory have found that specific mutations are selected by S. aureus that facilitate growth in CDM-R. However, these selected mutants synthesize arginine utilizing proline as a substrate rather than glutamate. In this study, we demonstrate that the ectopic expression of the argDCJB operon supports the growth of S. aureus in CDM-R, thus documenting the functionality of this pathway. Furthermore, suppressor mutants of S. aureus JE2 putA::Tn, which is defective in synthesizing arginine from proline, were selected on CDM-R agar. Genome sequencing revealed that these mutants had compensatory mutations within both spoVG, encoding an ortholog of the Bacillus subtilis stage V sporulation protein, and sarA, encoding the staphylococcal accessory regulator. Transcriptional studies document that argD expression is significantly increased when JE2 spoVG sarA was grown in CDM-R. Lastly, we found that a mutation in ahrC was required to induce argD expression in JE2 spoVG sarA when grown in an arginine-replete medium (CDM), suggesting that AhrC also functions to repress argDCJB in an arginine-dependent manner. In conclusion, these data indicate that the argDCJB operon is functional when transcribed in vitro and that SNPs within potential putative regulatory proteins are required to alleviate the repression.IMPORTANCEAlthough Staphylococcus aureus has the capability to synthesize all 20 amino acids, it is phenotypically auxotrophic for several amino acids including arginine. This work identifies putative regulatory proteins, including SpoVG, SarA, and AhrC, that function to inhibit the arginine biosynthetic pathways using glutamate as a substrate. Understanding the ultimate mechanisms of why S. aureus is selected to repress arginine biosynthetic pathways even in the absence of arginine will add to the growing body of work assessing the interactions between metabolism and S. aureus pathogenesis.
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Affiliation(s)
- Itidal Reslane
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Luke D. Handke
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Gabrielle F. Watson
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Dhananjay Shinde
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Jong-Sam Ahn
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Jennifer L. Endres
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Fareha Razvi
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Emily A. Gilbert
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Vinai C. Thomas
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - McKenzie K. Lehman
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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2
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Dailey KM, Small JM, Pullan JE, Winfree S, Vance KE, Orr M, Mallik S, Bayles KW, Hollingsworth MA, Brooks AE. An intravenous pancreatic cancer therapeutic: Characterization of CRISPR/Cas9n-modified Clostridium novyi-Non Toxic. PLoS One 2023; 18:e0289183. [PMID: 37963142 PMCID: PMC10645340 DOI: 10.1371/journal.pone.0289183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/12/2023] [Indexed: 11/16/2023] Open
Abstract
Clostridium novyi has demonstrated selective efficacy against solid tumors largely due to the microenvironment contained within dense tumor cores. The core of a solid tumor is typically hypoxic, acidic, and necrotic-impeding the penetration of current therapeutics. C. novyi is attracted to the tumor microenvironment and once there, can both lyse and proliferate while simultaneously re-activating the suppressed immune system. C. novyi systemic toxicity is easily mitigated by knocking out the phage DNA plasmid encoded alpha toxin resulting in C. novyi-NT; but, after intravenous injection spores are quickly cleared by phagocytosis before accomplishing significant tumor localization. C. novyi-NT could be designed to accomplish intravenous delivery with the potential to target all solid tumors and their metastases in a single dose. This study characterizes CRISPR/Cas9 modified C. novyi-NT to insert the gene for RGD, a tumor targeting peptide, expressed within the promoter region of a spore coat protein. Expression of the RGD peptide on the outer spore coat of C. novyi-NT indicates an increased capacity for tumor localization of C. novyi upon intravenous introduction based on the natural binding of RGD with the αvβ3 integrin commonly overexpressed on the epithelial tissue surrounding a tumor, and lead to immune stimulation.
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Affiliation(s)
- Kaitlin M. Dailey
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, United States of America
- Cell and Molecular Biology Program, North Dakota State University, Fargo, ND, United States of America
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, United States of America
| | - James M. Small
- Department of Pathology and Microbiology, Rocky Vista University, Parker, CO, United States of America
| | - Jessica E. Pullan
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, United States of America
- Department of Physical Science, Southern Utah University, Cedar City, UT, United States of America
| | - Seth Winfree
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, United States of America
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Krysten E. Vance
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Megan Orr
- Department of Statistics, North Dakota State University, Fargo, ND, United States of America
- Center for Diagnostics and Therapeutic Strategies in Pancreatic Cancer Biostatistics Core Facility, North Dakota State University, Fargo, ND, United States of America
| | - Sanku Mallik
- Cell and Molecular Biology Program, North Dakota State University, Fargo, ND, United States of America
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, United States of America
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Michael A. Hollingsworth
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, United States of America
| | - Amanda E. Brooks
- Cell and Molecular Biology Program, North Dakota State University, Fargo, ND, United States of America
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, United States of America
- Department of Research and Scholarly Activity, Rocky Vista University, Ivins, UT, United States of America
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3
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Sorlin A, López-Álvarez M, Rabbitt SJ, Alanizi AA, Shuere R, Bobba KN, Blecha J, Sakhamuri S, Evans MJ, Bayles KW, Flavell RR, Rosenberg OS, Sriram R, Desmet T, Nidetzky B, Engel J, Ohliger MA, Fraser JS, Wilson DM. Chemoenzymatic Syntheses of Fluorine-18-Labeled Disaccharides from [ 18F] FDG Yield Potent Sensors of Living Bacteria In Vivo. J Am Chem Soc 2023; 145:17632-17642. [PMID: 37535945 PMCID: PMC10436271 DOI: 10.1021/jacs.3c03338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Indexed: 08/05/2023]
Abstract
Chemoenzymatic techniques have been applied extensively to pharmaceutical development, most effectively when routine synthetic methods fail. The regioselective and stereoselective construction of structurally complex glycans is an elegant application of this approach that is seldom applied to positron emission tomography (PET) tracers. We sought a method to dimerize 2-deoxy-[18F]-fluoro-d-glucose ([18F]FDG), the most common tracer used in clinical imaging, to form [18F]-labeled disaccharides for detecting microorganisms in vivo based on their bacteria-specific glycan incorporation. When [18F]FDG was reacted with β-d-glucose-1-phosphate in the presence of maltose phosphorylase, the α-1,4- and α-1,3-linked products 2-deoxy-[18F]-fluoro-maltose ([18F]FDM) and 2-deoxy-2-[18F]-fluoro-sakebiose ([18F]FSK) were obtained. This method was further extended with the use of trehalose (α,α-1,1), laminaribiose (β-1,3), and cellobiose (β-1,4) phosphorylases to synthesize 2-deoxy-2-[18F]fluoro-trehalose ([18F]FDT), 2-deoxy-2-[18F]fluoro-laminaribiose ([18F]FDL), and 2-deoxy-2-[18F]fluoro-cellobiose ([18F]FDC). We subsequently tested [18F]FDM and [18F]FSK in vitro, showing accumulation by several clinically relevant pathogens including Staphylococcus aureus and Acinetobacter baumannii, and demonstrated their specific uptake in vivo. Both [18F]FDM and [18F]FSK were stable in human serum with high accumulation in preclinical infection models. The synthetic ease and high sensitivity of [18F]FDM and [18F]FSK to S. aureus including methicillin-resistant (MRSA) strains strongly justify clinical translation of these tracers to infected patients. Furthermore, this work suggests that chemoenzymatic radiosyntheses of complex [18F]FDG-derived oligomers will afford a wide array of PET radiotracers for infectious and oncologic applications.
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Affiliation(s)
- Alexandre
M. Sorlin
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Marina López-Álvarez
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Sarah J. Rabbitt
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Aryn A. Alanizi
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Rebecca Shuere
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Kondapa Naidu Bobba
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Joseph Blecha
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Sasank Sakhamuri
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Michael J. Evans
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Kenneth W. Bayles
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Robert R. Flavell
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
| | - Oren S. Rosenberg
- Department
of Medicine University of California, San
Francisco, San Francisco, California 94158, United States
| | - Renuka Sriram
- Department
of Biotechnology, Ghent University, Gent B-9000, Belgium
| | - Tom Desmet
- Department
of Biotechnology, Ghent University, Gent B-9000, Belgium
| | - Bernd Nidetzky
- Institute
of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz 8010, Austria
| | - Joanne Engel
- Department
of Biotechnology, Ghent University, Gent B-9000, Belgium
| | - Michael A. Ohliger
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
- Department
of Radiology Zuckerberg San Francisco General
Hospital, San Francisco, California 94110, United States
| | - James S. Fraser
- Department
of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California 94158, United States
| | - David M. Wilson
- Department
of Radiology and Biomedical Imaging, University
of California, San Francisco, San Francisco, California 94158, United States
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4
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Roe JM, Seely K, Bussard CJ, Eischen Martin E, Mouw EG, Bayles KW, Hollingsworth MA, Brooks AE, Dailey KM. Hacking the Immune Response to Solid Tumors: Harnessing the Anti-Cancer Capacities of Oncolytic Bacteria. Pharmaceutics 2023; 15:2004. [PMID: 37514190 PMCID: PMC10384176 DOI: 10.3390/pharmaceutics15072004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/13/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
Oncolytic bacteria are a classification of bacteria with a natural ability to specifically target solid tumors and, in the process, stimulate a potent immune response. Currently, these include species of Klebsiella, Listeria, Mycobacteria, Streptococcus/Serratia (Coley's Toxin), Proteus, Salmonella, and Clostridium. Advancements in techniques and methodology, including genetic engineering, create opportunities to "hijack" typical host-pathogen interactions and subsequently harness oncolytic capacities. Engineering, sometimes termed "domestication", of oncolytic bacterial species is especially beneficial when solid tumors are inaccessible or metastasize early in development. This review examines reported oncolytic bacteria-host immune interactions and details the known mechanisms of these interactions to the protein level. A synopsis of the presented membrane surface molecules that elicit particularly promising oncolytic capacities is paired with the stimulated localized and systemic immunogenic effects. In addition, oncolytic bacterial progression toward clinical translation through engineering efforts are discussed, with thorough attention given to strains that have accomplished Phase III clinical trial initiation. In addition to therapeutic mitigation after the tumor has formed, some bacterial species, referred to as "prophylactic", may even be able to prevent or "derail" tumor formation through anti-inflammatory capabilities. These promising species and their particularly favorable characteristics are summarized as well. A complete understanding of the bacteria-host interaction will likely be necessary to assess anti-cancer capacities and unlock the full cancer therapeutic potential of oncolytic bacteria.
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Affiliation(s)
- Jason M Roe
- College of Osteopathic Medicine, Rocky Vista University, Ivins, UT 84738, USA
| | - Kevin Seely
- College of Osteopathic Medicine, Rocky Vista University, Ivins, UT 84738, USA
| | - Caleb J Bussard
- College of Osteopathic Medicine, Rocky Vista University, Parker, CO 80130, USA
| | | | - Elizabeth G Mouw
- College of Osteopathic Medicine, Rocky Vista University, Ivins, UT 84738, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Michael A Hollingsworth
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Amanda E Brooks
- College of Osteopathic Medicine, Rocky Vista University, Ivins, UT 84738, USA
- College of Osteopathic Medicine, Rocky Vista University, Parker, CO 80130, USA
- Office of Research & Scholarly Activity, Rocky Vista University, Ivins, UT 84738, USA
| | - Kaitlin M Dailey
- Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, NE 68198, USA
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5
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Sorlin AM, López-Álvarez M, Rabbitt SJ, Alanizi AA, Shuere R, Bobba KN, Blecha J, Sakhamuri S, Evans MJ, Bayles KW, Flavell RR, Rosenberg OS, Sriram R, Desmet T, Nidetzky B, Engel J, Ohliger MA, Fraser JS, Wilson DM. Chemoenzymatic syntheses of fluorine-18-labeled disaccharides from [ 18 F]FDG yield potent sensors of living bacteria in vivo. bioRxiv 2023:2023.05.20.541529. [PMID: 37293043 PMCID: PMC10245702 DOI: 10.1101/2023.05.20.541529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chemoenzymatic techniques have been applied extensively to pharmaceutical development, most effectively when routine synthetic methods fail. The regioselective and stereoselective construction of structurally complex glycans is an elegant application of this approach, that is seldom applied to positron emission tomography (PET) tracers. We sought a method to dimerize 2-deoxy-[ 18 F]-fluoro-D-glucose ([ 18 F]FDG), the most common tracer used in clinical imaging, to form [ 18 F]-labeled disaccharides for detecting microorganisms in vivo based on their bacteria-specific glycan incorporation. When [ 18 F]FDG was reacted with β-D-glucose-1-phosphate in the presence of maltose phosphorylase, both the α-1,4 and α-1,3-linked products 2-deoxy-[ 18 F]-fluoro-maltose ([ 18 F]FDM) and 2-deoxy-2-[ 18 F]-fluoro-sakebiose ([ 18 F]FSK) were obtained. This method was further extended with the use of trehalose (α,α-1,1), laminaribiose (β-1,3), and cellobiose (β-1,4) phosphorylases to synthesize 2-deoxy-2-[ 18 F]fluoro-trehalose ([ 18 F]FDT), 2-deoxy-2-[ 18 F]fluoro-laminaribiose ([ 18 F]FDL), and 2-deoxy-2-[ 18 F]fluoro-cellobiose ([ 18 F]FDC). We subsequently tested [ 18 F]FDM and [ 18 F]FSK in vitro, showing accumulation by several clinically relevant pathogens including Staphylococcus aureus and Acinetobacter baumannii, and demonstrated their specific uptake in vivo. The lead sakebiose-derived tracer [ 18 F]FSK was stable in human serum and showed high uptake in preclinical models of myositis and vertebral discitis-osteomyelitis. Both the synthetic ease, and high sensitivity of [ 18 F]FSK to S. aureus including methicillin-resistant (MRSA) strains strongly justify clinical translation of this tracer to infected patients. Furthermore, this work suggests that chemoenzymatic radiosyntheses of complex [ 18 F]FDG-derived oligomers will afford a wide array of PET radiotracers for infectious and oncologic applications.
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6
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Shakyawar SK, Mishra NK, Vellichirammal NN, Cary L, Helikar T, Powers R, Oberley-Deegan RE, Berkowitz DB, Bayles KW, Singh VK, Guda C. A Review of Radiation-Induced Alterations of Multi-Omic Profiles, Radiation Injury Biomarkers, and Countermeasures. Radiat Res 2023; 199:89-111. [PMID: 36368026 PMCID: PMC10279411 DOI: 10.1667/rade-21-00187.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/24/2022] [Indexed: 11/13/2022]
Abstract
Increasing utilization of nuclear power enhances the risks associated with industrial accidents, occupational hazards, and the threat of nuclear terrorism. Exposure to ionizing radiation interferes with genomic stability and gene expression resulting in the disruption of normal metabolic processes in cells and organs by inducing complex biological responses. Exposure to high-dose radiation causes acute radiation syndrome, which leads to hematopoietic, gastrointestinal, cerebrovascular, and many other organ-specific injuries. Altered genomic variations, gene expression, metabolite concentrations, and microbiota profiles in blood plasma or tissue samples reflect the whole-body radiation injuries. Hence, multi-omic profiles obtained from high-resolution omics platforms offer a holistic approach for identifying reliable biomarkers to predict the radiation injury of organs and tissues resulting from radiation exposures. In this review, we performed a literature search to systematically catalog the radiation-induced alterations from multi-omic studies and radiation countermeasures. We covered radiation-induced changes in the genomic, transcriptomic, proteomic, metabolomic, lipidomic, and microbiome profiles. Furthermore, we have covered promising multi-omic biomarkers, FDA-approved countermeasure drugs, and other radiation countermeasures that include radioprotectors and radiomitigators. This review presents an overview of radiation-induced alterations of multi-omics profiles and biomarkers, and associated radiation countermeasures.
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Affiliation(s)
- Sushil K Shakyawar
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Nitish K Mishra
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Neetha N Vellichirammal
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Lynnette Cary
- Division of Radioprotectants, Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Tomáš Helikar
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln NE 65888, USA
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln NE 65888, USA
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln NE 68588, USA
| | - Rebecca E Oberley-Deegan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - David B Berkowitz
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln NE 65888, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Vijay K Singh
- Division of Radioprotectants, Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Chittibabu Guda
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Center for Biomedical Informatics Research and Innovation, University of Nebraska Medical Center, Omaha, NE 68198, USA
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7
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Struble LR, Smith AL, Lutz WE, Grubbs G, Sagar S, Bayles KW, Radhakrishnan P, Khurana S, El‐Gamal D, Borgstahl GEO. Insect cell expression and purification of recombinant
SARS‐COV
‐2 spike proteins that demonstrate
ACE2
binding. Protein Sci 2022; 31:e4300. [PMID: 35481636 PMCID: PMC8996471 DOI: 10.1002/pro.4300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/10/2022] [Accepted: 03/11/2022] [Indexed: 11/21/2022]
Abstract
The COVID‐19 pandemic caused by SARS‐CoV‐2 infection has led to socio‐economic shutdowns and the loss of over 5 million lives worldwide. There is a need for the identification of therapeutic targets to treat COVID‐19. SARS‐CoV‐2 spike is a target of interest for the development of therapeutic targets. We developed a robust SARS‐CoV‐2 S spike expression and purification protocol from insect cells and studied four recombinant SARS‐CoV‐2 spike protein constructs based on the original SARS‐CoV‐2 sequence using a baculovirus expression system: a spike protein receptor‐binding domain that includes the SD1 domain (RBD) coupled to a fluorescent tag (S‐RBD‐eGFP), spike ectodomain coupled to a fluorescent tag (S‐Ecto‐eGFP), spike ectodomain with six proline mutations and a foldon domain (S‐Ecto‐HexaPro(+F)), and spike ectodomain with six proline mutations without the foldon domain (S‐Ecto‐HexaPro(‐F)). We tested the yield of purified protein expressed from the insect cell lines Spodoptera frugiperda (Sf9) and Trichoplusia ni (Tni) and compared it to previous research using mammalian cell lines to determine changes in protein yield. We demonstrated quick and inexpensive production of functional glycosylated spike protein of high purity capable of recognizing and binding to the angiotensin converting enzyme 2 (ACE2) receptor. To further confirm functionality, we demonstrate binding of eGFP fused construct of the spike ectodomain (S‐Ecto‐eGFP) to surface ACE2 receptors on lung epithelial cells by flow cytometry analysis and show that it can be decreased by means of receptor manipulation (blockade or downregulation).
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Affiliation(s)
- Lucas R. Struble
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
| | - Audrey L. Smith
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
| | - William E. Lutz
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
| | - Gabrielle Grubbs
- Division of Viral Products, Center for Biologics Evaluation and Research (CBER) FDA Silver Spring Maryland USA
| | - Satish Sagar
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology University of Nebraska Medical Center Omaha Nebraska USA
| | - Prakash Radhakrishnan
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
- Department of Pathology and Microbiology University of Nebraska Medical Center Omaha Nebraska USA
- Fred and Pamela Buffet Cancer Center University of Nebraska Medical Center Omaha Nebraska USA
- Department of Genetics, Cell Biology and Anatomy University of Nebraska Medical Center Omaha Nebraska USA
| | - Surender Khurana
- Division of Viral Products, Center for Biologics Evaluation and Research (CBER) FDA Silver Spring Maryland USA
| | - Dalia El‐Gamal
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
- Fred and Pamela Buffet Cancer Center University of Nebraska Medical Center Omaha Nebraska USA
| | - Gloria E. O. Borgstahl
- Eppley Institute for Research in Cancer and Allied Diseases University of Nebraska Media Center Omaha Nebraska USA
- Fred and Pamela Buffet Cancer Center University of Nebraska Medical Center Omaha Nebraska USA
- Department of Genetics, Cell Biology and Anatomy University of Nebraska Medical Center Omaha Nebraska USA
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8
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Laliwala A, Svechkarev D, Sadykov MR, Endres J, Bayles KW, Mohs AM. Simpler Procedure and Improved Performance for Pathogenic Bacteria Analysis with a Paper-Based Ratiometric Fluorescent Sensor Array. Anal Chem 2022; 94:2615-2624. [PMID: 35073053 PMCID: PMC10091516 DOI: 10.1021/acs.analchem.1c05021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Bacterial infections are the leading cause of morbidity and mortality in the world, particularly due to a delay in treatment and misidentification of the bacterial species causing the infection. Therefore, rapid and accurate identification of these pathogens has been of prime importance. The conventional diagnostic techniques include microbiological, biochemical, and genetic analyses, which are time-consuming, require large sample volumes, expensive equipment, reagents, and trained personnel. In response, we have now developed a paper-based ratiometric fluorescent sensor array. Environment-sensitive fluorescent dyes (3-hydroxyflavone derivatives) pre-adsorbed on paper microzone plates fabricated using photolithography, upon interaction with bacterial cell envelopes, generate unique fluorescence response patterns. The stability and reproducibility of the sensor array response were thoroughly investigated, and the analysis procedure was refined for optimal performance. Using neural networks for response pattern analysis, the sensor was able to identify 16 bacterial species and recognize their Gram status with an accuracy rate greater than 90%. The paper-based sensor was stable for up to 6 months after fabrication and required 30 times lower dye and sample volumes as compared to the analogous solution-based sensor. Therefore, this approach opens avenues to a state-of-the-art diagnostic tool that can be potentially translated into clinical applications in low-resource environments.
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Affiliation(s)
- Aayushi Laliwala
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6858, United States
| | - Denis Svechkarev
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6858, United States
| | - Marat R. Sadykov
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Jennifer Endres
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Aaron M. Mohs
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska 68198-6858, United States
- Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska 68198-6858, United States
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9
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Dailey KM, Vance K, McAndrews K, Jacobson RI, Delgado J, Johnson PR, Woolery TM, Orr M, Kim J, Mallik S, Bayles KW, Hollingsworth MA, Brooks AE. Abstract PO-037: Development of an RGD CRISPR-modified Clostridium novyi NT spores as an intravenous oncotherapy. Cancer Res 2021. [DOI: 10.1158/1538-7445.panca21-po-037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The efficacy of current oncotherapeutics is largely limited by an inability to access avascular tissues, which is in part responsible for forty years of stagnant pancreatic cancer statistics where the median survival remains a mere six months. Oncolytic bacteria such as Clostridium novyi-NT overcome this challenge with its ultrasensitive, innate affinity for hypoxic/necrotic areas found at the center of solid tumors and their metastases. While preclinical and clinical data from intratumoral injections of C. novyi-NT are promising, many tumors are inaccessible to such injections. Preclinical trials of analogous IV injections have uncovered other obstacles such as rapid clearance of C. novyi-NT by the immune system independent of septic complications. To mitigate rapid clearance, CRISPR/Cas9n was used to genetically modify a non-toxic form of C. novyi-NT to express a tumor targeting RGD peptide on the spore surface. Through this novel, first of its kind, methodology, spores with stronger affinity to a surface coated with the targeted binding partner of RGD, aVb3 integrin, have been generated. Importantly, there was no statistically significant difference in the genetically modified spore’s capacity for sporulation or germination when compared to unmodified C. novyi-NT spores, nor was a difference in lytic capacity observed, suggesting no relevant off-target effects from genomic modification. Biodistribution and efficacy of non-toxic RGD-modified spores was evaluated in an immunocompetent, syngeneic, pancreatic cancer murine model. Ongoing efforts to characterize the biodistribution and efficacy of the intravenously injected RGD-modified C. novyi-NT include the application of multiplex immunofluorescence, laser microdissection, and live, whole animal imaging. Supported as a pilot project by funds from NIH COBRE grant 1P20GM109024, Doctoral Dissertation Funds to KMD from NDSU, and by discretionary funds from investigators at UNMC.
Citation Format: Kaitlin M. Dailey, Krysten Vance, Kyle McAndrews, Reed I. Jacobson, Jandro Delgado, Paige R. Johnson, Taylor M. Woolery, Megan Orr, Jiha Kim, Sanku Mallik, Kenneth W. Bayles, Michael A. Hollingsworth, Amanda E. Brooks. Development of an RGD CRISPR-modified Clostridium novyi NT spores as an intravenous oncotherapy [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-037.
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Affiliation(s)
- Kaitlin M. Dailey
- 1Eppley Institute for Cancer Research, University of Nebraska Medical Center, and Cell and Molecular Biology Program, Pharmaceutical Sciences Department, North Dakota State University, Omaha, NE,
| | - Krysten Vance
- 2Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, NE,
| | - Kyle McAndrews
- 3Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, Omaha, NE,
| | - Reed I. Jacobson
- 4Department of Biological Sciences, North Dakota State University, Fargo, ND,
| | - Jandro Delgado
- 4Department of Biological Sciences, North Dakota State University, Fargo, ND,
| | - Paige R. Johnson
- 5Cell and Molecular Biology Program, Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND,
| | - Taylor M. Woolery
- 5Cell and Molecular Biology Program, Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND,
| | - Megan Orr
- 6Department of Statistics, North Dakota State University, Fargo, ND,
| | - Jiha Kim
- 7Cell and Molecular Biology Program, Pharmaceutical Sciences Department and Department of Biological Sciences, North Dakota State University, Fargo, ND,
| | - Sanku Mallik
- 5Cell and Molecular Biology Program, Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND,
| | - Kenneth W. Bayles
- 8Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE,
| | | | - Amanda E. Brooks
- 9Cell and Molecular Biology Program, Pharmaceutical Sciences Department, North Dakota State University, Fargo, ND, and Department of Research and Scholarly Activity, Rocky Vista University, Ivins, UT
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10
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Prahlad J, Struble LR, Lutz WE, Wallin SA, Khurana S, Schnaubelt A, Broadhurst MJ, Bayles KW, Borgstahl GEO. CyDisCo production of functional recombinant SARS-CoV-2 spike receptor binding domain. Protein Sci 2021; 30:1983-1990. [PMID: 34191362 PMCID: PMC8376421 DOI: 10.1002/pro.4152] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 06/14/2021] [Accepted: 06/22/2021] [Indexed: 01/05/2023]
Abstract
The COVID‐19 pandemic caused by SARS‐CoV‐2 has applied significant pressure on overtaxed healthcare around the world, underscoring the urgent need for rapid diagnosis and treatment. We have developed a bacterial strategy for the expression and purification of a SARS‐CoV‐2 spike protein receptor binding domain (RBD) that includes the SD1 domain. Bacterial cytoplasm is a reductive environment, which is problematic when the recombinant protein of interest requires complicated folding and/or processing. The use of the CyDisCo system (cytoplasmic disulfide bond formation in E. coli) bypasses this issue by pre‐expressing a sulfhydryl oxidase and a disulfide isomerase, allowing the recombinant protein to be correctly folded with disulfide bonds for protein integrity and functionality. We show that it is possible to quickly and inexpensively produce an active RBD in bacteria that is capable of recognizing and binding to the ACE2 (angiotensin‐converting enzyme) receptor as well as antibodies in COVID‐19 patient sera.
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Affiliation(s)
- Janani Prahlad
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Lucas R Struble
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - William E Lutz
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Savanna A Wallin
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Surender Khurana
- Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, Maryland, USA
| | - Andy Schnaubelt
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Mara J Broadhurst
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Gloria E O Borgstahl
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA.,Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, USA
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11
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Sagar S, Rathinavel AK, Lutz WE, Struble LR, Khurana S, Schnaubelt AT, Mishra NK, Guda C, Palermo NY, Broadhurst MJ, Hoffmann T, Bayles KW, Reid SPM, Borgstahl GEO, Radhakrishnan P. Bromelain inhibits SARS-CoV-2 infection via targeting ACE-2, TMPRSS2, and spike protein. Clin Transl Med 2021; 11:e281. [PMID: 33635001 PMCID: PMC7811777 DOI: 10.1002/ctm2.281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/23/2020] [Accepted: 12/28/2020] [Indexed: 12/16/2022] Open
Affiliation(s)
- Satish Sagar
- Eppley Institute for Research in Cancer and Allied DiseasesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Ashok Kumar Rathinavel
- Eppley Institute for Research in Cancer and Allied DiseasesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - William E. Lutz
- Eppley Institute for Research in Cancer and Allied DiseasesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Lucas R. Struble
- Eppley Institute for Research in Cancer and Allied DiseasesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Surender Khurana
- Division of Viral ProductsCenter for Biologics Evaluation and Research (CBER)FDASilver SpringMarylandUSA
| | - Andy T. Schnaubelt
- Department of Pathology and MicrobiologyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Nitish Kumar Mishra
- Department of GeneticsCell Biology and AnatomyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Chittibabu Guda
- Department of GeneticsCell Biology and AnatomyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
- Fred & Pamela Buffett Cancer CenterUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Nicholas Y. Palermo
- Computational Chemistry CoreUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Mara J. Broadhurst
- Department of Pathology and MicrobiologyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Tobias Hoffmann
- Advanced Light and Electron MicroscopyCentre for Biological Threats and Special Pathogens 4 (ZBS 4)Robert Koch InstituteBerlinGermany
| | - Kenneth W. Bayles
- Department of Pathology and MicrobiologyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - St. Patrick M. Reid
- Department of Pathology and MicrobiologyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Gloria E. O. Borgstahl
- Eppley Institute for Research in Cancer and Allied DiseasesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
- Fred & Pamela Buffett Cancer CenterUniversity of Nebraska Medical CenterOmahaNebraskaUSA
| | - Prakash Radhakrishnan
- Eppley Institute for Research in Cancer and Allied DiseasesUniversity of Nebraska Medical CenterOmahaNebraskaUSA
- Department of Pathology and MicrobiologyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
- Department of GeneticsCell Biology and AnatomyUniversity of Nebraska Medical CenterOmahaNebraskaUSA
- Fred & Pamela Buffett Cancer CenterUniversity of Nebraska Medical CenterOmahaNebraskaUSA
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12
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Sagar S, Rathinavel AK, Lutz WE, Struble LR, Khurana S, Schnaubelt AT, Mishra NK, Guda C, Broadhurst MJ, Reid SPM, Bayles KW, Borgstahl GEO, Radhakrishnan P. Bromelain Inhibits SARS-CoV-2 Infection in VeroE6 Cells. bioRxiv 2020:2020.09.16.297366. [PMID: 32995771 PMCID: PMC7523097 DOI: 10.1101/2020.09.16.297366] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The initial interaction between Transmembrane Serine Protease 2 (TMPRSS2) primed SARS-CoV-2 spike (S) protein and host cell receptor angiotensin-converting enzyme 2 (ACE-2) is a pre-requisite step for this novel coronavirus pathogenesis. Here, we expressed a GFP-tagged SARS-CoV-2 S-Ectodomain in Tni insect cells. That contained sialic acid-enriched N- and O-glycans. Surface resonance plasmon (SPR) and Luminex assay showed that the purified S-Ectodomain binding to human ACE-2 and immunoreactivity with COVID-19 positive samples. We demonstrate that bromelain (isolated from pineapple stem and used as a dietary supplement) treatment diminishes the expression of ACE-2 and TMPRSS2 in VeroE6 cells and dramatically lowers the expression of S-Ectodomain. Importantly, bromelain treatment reduced the interaction between S-Ectodomain and VeroE6 cells. Most importantly, bromelain treatment significantly diminished the SARS-CoV-2 infection in VeroE6 cells. Altogether, our results suggest that bromelain or bromelain rich pineapple stem may be used as an antiviral against COVID-19. HIGHLIGHTS Bromelain inhibits / cleaves the expression of ACE-2 and TMPRSS2Bromelain cleaves / degrades SARS-CoV-2 spike proteinBromelain inhibits S-Ectodomain binding and SARS-CoV-2 infection.
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Affiliation(s)
- Satish Sagar
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Ashok Kumar Rathinavel
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - William E. Lutz
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Lucas R. Struble
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Surender Khurana
- Division of Viral Products, Center for Biologics Evaluation and Research (CBER), FDA, Silver Spring, MD 20871, USA
| | - Andy T Schnaubelt
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Nitish Kumar Mishra
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Chittibabu Guda
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Mara J. Broadhurst
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - St. Patrick M. Reid
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
| | - Gloria E. O. Borgstahl
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA 68198
| | - Prakash Radhakrishnan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, USA 68198
- Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, USA 68198
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13
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Abstract
Transposon mutagenesis is one of the most widely used strategies to generate a large number of random mutations within a bacterial genome and then to precisely identify the mutated sites. The generation of sequence-defined transposon mutant libraries that are composed of a collection of different mutants, each containing a single transposon insertion mutation within nearly all of the nonessential genes within the genome, is a rapid and reliable way to enhance the study of gene function. In this chapter, we describe the process to generate a sequence-defined transposon mutant library in Staphylococcus aureus utilizing the mariner-based bursa aurealis transposon.
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Affiliation(s)
- Jennifer L Endres
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, USA
| | - Vijaya Kumar Yajjala
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, USA.
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14
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Svechkarev D, Sadykov MR, Houser LJ, Bayles KW, Mohs AM. Fluorescent Sensor Arrays Can Predict and Quantify the Composition of Multicomponent Bacterial Samples. Front Chem 2020; 7:916. [PMID: 32010667 PMCID: PMC6974461 DOI: 10.3389/fchem.2019.00916] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/17/2019] [Indexed: 11/25/2022] Open
Abstract
Fast and reliable identification of infectious disease agents is among the most important challenges for the healthcare system. The discrimination of individual components of mixed infections represents a particularly difficult task. In the current study we further expand the functionality of a ratiometric sensor array technology based on small-molecule environmentally-sensitive organic dyes, which can be successfully applied for the analysis of mixed bacterial samples. Using pattern recognition methods and data from pure bacterial species, we demonstrate that this approach can be used to quantify the composition of mixtures, as well as to predict their components with the accuracy of ~80% without the need to acquire additional reference data. The described approach significantly expands the functionality of sensor arrays and provides important insights into data processing for the analysis of other complex samples.
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Affiliation(s)
- Denis Svechkarev
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Marat R Sadykov
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Lucas J Houser
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, United States
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Aaron M Mohs
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE, United States.,Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, United States
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15
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Abstract
Rapid and reliable identification of pathogenic microorganisms is of great importance for human and animal health. Most conventional approaches are time-consuming and require expensive reagents, sophisticated equipment, trained personnel, and special storage and handling conditions. Sensor arrays based on small molecules offer a chemically stable and cost-effective alternative. Here we present a ratiometric fluorescent sensor array based on the derivatives of 2-(4'- N, N-dimethylamino)-3-hydroxyflavone and investigate its ability to provide a dual-channel ratiometric response. We demonstrate that, by using discriminant analysis of the sensor array responses, it is possible to effectively distinguish between eight bacterial species and recognize their Gram status. Thus, multiple parameters can be derived from the same data set. Moreover, the predictive potential of this sensor array is discussed, and its ability to analyze unknown samples beyond the list of species used for the training matrix is demonstrated. The proposed sensor array and analysis strategies open new avenues for the development of advanced ratiometric sensors for multiparametric analysis.
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Affiliation(s)
- Denis Svechkarev
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6858, United States
| | - Marat R. Sadykov
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5900, United States
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5900, United States
| | - Aaron M. Mohs
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6858, United States
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198-6858, United States
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-6858, United States
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16
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Abstract
Recent studies have revealed an important role for the Staphylococcus aureus CidC enzyme in cell death during the stationary phase and in biofilm development and have contributed to our understanding of the metabolic processes that are important in the induction of bacterial programmed cell death (PCD). To gain more insight into the characteristics of this enzyme, we performed an in-depth biochemical and biophysical analysis of its catalytic properties. In vitro experiments show that this flavoprotein catalyzes the oxidative decarboxylation of pyruvate to acetate and carbon dioxide. CidC efficiently reduces menadione, but not CoenzymeQ0, suggesting a specific role in the S. aureus respiratory chain. CidC exists as a monomer under neutral-pH conditions but tends to aggregate and bind to artificial lipid membranes at acidic pH, resulting in enhanced enzymatic activity. Unlike its Escherichia coli counterpart, PoxB, CidC does not appear to be activated by other amphiphiles like Triton X-100 or octyl β-d-glucopyranoside. In addition, only reduced CidC is protected from proteolytic cleavage by chymotrypsin, and unlike its homologues in other bacteria, protease treatment does not increase CidC enzymatic activity. Finally, CidC exhibits maximal activity at pH 5.5-5.8 and negligible activity at pH 7-8. The results of this study are consistent with a model in which CidC functions as a pyruvate:menaquinone oxidoreductase whose activity is induced at the cellular membrane during cytoplasmic acidification, a process previously shown to be important for the induction of bacterial PCD.
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Affiliation(s)
- Xinyan Zhang
- Department of Pharmaceutical Sciences and ‡Department of Pathology & Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198-5900, United States
| | - Kenneth W Bayles
- Department of Pharmaceutical Sciences and ‡Department of Pathology & Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198-5900, United States
| | - Sorin Luca
- Department of Pharmaceutical Sciences and ‡Department of Pathology & Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198-5900, United States
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17
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Sadykov MR, Ahn JS, Widhelm TJ, Eckrich VM, Endres JL, Driks A, Rutkowski GE, Wingerd KL, Bayles KW. Poly(3-hydroxybutyrate) fuels the tricarboxylic acid cycle andde novolipid biosynthesis duringBacillus anthracissporulation. Mol Microbiol 2017; 104:793-803. [DOI: 10.1111/mmi.13665] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Marat R. Sadykov
- Department of Pathology and Microbiology; University of Nebraska Medical Center; Omaha NE 68198 USA
| | - Jong-Sam Ahn
- Department of Pathology and Microbiology; University of Nebraska Medical Center; Omaha NE 68198 USA
| | - Todd J. Widhelm
- Department of Pathology and Microbiology; University of Nebraska Medical Center; Omaha NE 68198 USA
| | - Valerie M. Eckrich
- Department of Pathology and Microbiology; University of Nebraska Medical Center; Omaha NE 68198 USA
| | - Jennifer L. Endres
- Department of Pathology and Microbiology; University of Nebraska Medical Center; Omaha NE 68198 USA
| | - Adam Driks
- Department of Microbiology and Immunology; Loyola University Chicago, Stritch School of Medicine; Maywood IL 60153 USA
| | | | | | - Kenneth W. Bayles
- Department of Pathology and Microbiology; University of Nebraska Medical Center; Omaha NE 68198 USA
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18
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Abstract
Chronic biofilm-associated infections caused by Staphylococcus aureus often lead to significant increases in morbidity and mortality, particularly when associated with indwelling medical devices. This has triggered a great deal of research attempting to understand the molecular mechanisms that control S. aureus biofilm formation and the basis for the recalcitrance of these multicellular structures to antibiotic therapy. The purpose of this review is to summarize our current understanding of S. aureus biofilm development, focusing on the description of a newly-defined, five-stage model of biofilm development and the mechanisms required for each stage. Importantly, this model includes an alternate view of the processes involved in microcolony formation in S. aureus and suggests that these structures originate as a result of stochastically regulated metabolic heterogeneity and proliferation within a maturing biofilm population, rather than a subtractive process involving the release of cell clusters from a thick, unstructured biofilm. Importantly, it is proposed that this new model of biofilm development involves the genetically programmed generation of metabolically distinct subpopulations of cells, resulting in an overall population that is better able to adapt to rapidly changing environmental conditions.
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Affiliation(s)
- Derek E Moormeier
- Center for Staphylococcal Research, Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kenneth W Bayles
- Center for Staphylococcal Research, Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
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19
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Udumula V, Endres JL, Harper CN, Jaramillo L, Zhong HA, Bayles KW, Conda-Sheridan M. Simple synthesis of endophenazine G and other phenazines and their evaluation as anti-methicillin-resistant Staphylococcus aureus agents. Eur J Med Chem 2017; 125:710-721. [DOI: 10.1016/j.ejmech.2016.09.079] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/23/2016] [Accepted: 09/24/2016] [Indexed: 02/05/2023]
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20
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Glanzer JG, Endres JL, Byrne BM, Liu S, Bayles KW, Oakley GG. Identification of inhibitors for single-stranded DNA-binding proteins in eubacteria. J Antimicrob Chemother 2016; 71:3432-3440. [PMID: 27609050 DOI: 10.1093/jac/dkw340] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 06/17/2016] [Accepted: 07/19/2016] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES The increasing threat of drug-resistant bacteria establishes a continuing need for the development of new strategies to fight infection. We examine the inhibition of the essential single-stranded DNA-binding proteins (SSBs) SSBA and SSBB as a potential antimicrobial therapy due to their importance in DNA replication, activating the SOS response and promoting competence-based mechanisms of resistance by incorporating new DNA. METHODS Purified recombinant SSBs from Gram-positive (Staphylococcus aureus and Bacillus anthracis) and Gram-negative (Escherichia coli and Francisella tularensis) bacteria were assessed in a high-throughput screen for inhibition of duplex DNA unwinding by small molecule inhibitors. Secondary electrophoretic mobility shift assays further validated the top hits that were then tested for MICs using in vitro assays. RESULTS We have identified compounds that show cross-reactivity in vitro, as well as inhibition of both F. tularensis and B. anthracis SSBA. Five compounds were moderately toxic to at least two of the four bacterial strains in vivo, including two compounds that were selectively non-toxic to human cells, 9-hydroxyphenylfluoron and purpurogallin. Three of the SSBA inhibitors also inhibited S. aureus SSBB in Gram-positive bacteria. CONCLUSIONS Results from our study support the potential for SSB inhibitors as broad-spectrum antibacterial agents, with dual targeting capabilities against Gram-positive bacteria.
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Affiliation(s)
- Jason G Glanzer
- Department of Oral Biology, University of Nebraska Medical Center, Omaha, NE 68583, USA.,RPAcheQ, 16612 Martha Circle, Suite 510, Omaha, NE 68130, USA
| | - Jennifer L Endres
- Department of Pathology and Microbiology, University of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, NE 68198-6495, USA
| | - Brendan M Byrne
- Department of Oral Biology, University of Nebraska Medical Center, Omaha, NE 68583, USA
| | - Shengqin Liu
- Department of Oral Biology, University of Nebraska Medical Center, Omaha, NE 68583, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, NE 68198-6495, USA
| | - Greg G Oakley
- Department of Oral Biology, University of Nebraska Medical Center, Omaha, NE 68583, USA .,Eppley Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
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21
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Yang Z, Liu Y, Ahn J, Qiao Z, Endres JL, Gautam N, Huang Y, Li J, Zheng J, Alnouti Y, Bayles KW, Li R. Novel fluorinated pyrrolomycins as potent anti-staphylococcal biofilm agents: Design, synthesis, pharmacokinetics and antibacterial activities. Eur J Med Chem 2016; 124:129-137. [PMID: 27565555 DOI: 10.1016/j.ejmech.2016.08.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 07/20/2016] [Accepted: 08/09/2016] [Indexed: 12/15/2022]
Abstract
Staphylococcus aureus (SA) is a major cause of hospital- and community-associated bacterial infections in the U.S. and around the world. These infections have become increasingly difficult to treat due to the propensity to develop antibiotic resistance and form biofilm. To date, no antibiofilm agents are available for clinical use. To add to the repertoire of antibiotics for clinical use and to provide novel agents for combating both SA and biofilm infections, we previously reported marinopyrroles as potent anti-SA agents. In this study, we used fragment-based and bioisostere approaches to design and synthesize a series of novel fluorinated pyrrolomycins for the first time, performed analyses of their physicochemical and drug-like properties, and investigated structure activity relationships and pharmacokinetics. These promising fluorinated pyrrolomycins demonstrate potent antibacterial activity against SA with favorable drug-like properties and pharmacokinetic profiles. Importantly, these compounds kill staphylococcal biofilm-associated cells with a lack of mammalian cell cytotoxicity and no occurrence of bacterial resistance. Our novel fluorinated pyrrolomycin 4 has a clogP value of 4.1, an MIC of 73 ng/mL, MBC of 4 μg/mL, kill staphylococcal-associated biofilm at 8 μg/mL, bioavailability of 35%, and the elimination half-life of 6.04 h and 6.75 h by intravenous and oral administration, respectively. This is the first report of comprehensive drug discovery studies on pyrrolomycin-based antibiotics.
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Affiliation(s)
- Zunhua Yang
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States
| | - Yan Liu
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States
| | - Jongsam Ahn
- Department of Pathology and Microbiology, United States
| | - Zhen Qiao
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States
| | | | - Nagsen Gautam
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States
| | - Yunlong Huang
- Department of Pharmacology and Experimental Neuroscience, United States
| | - Jerry Li
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States
| | - Jialin Zheng
- Department of Pathology and Microbiology, United States; Department of Pharmacology and Experimental Neuroscience, United States
| | - Yazen Alnouti
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, United States; Center for Staphylococcal Research, United States
| | - Rongshi Li
- UNMC Center for Drug Discovery and Department of Pharmaceutical Sciences, United States; Center for Staphylococcal Research, United States; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, 986125 Nebraska Medical Center, Omaha, NE 68198, United States.
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22
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Chaudhari SS, Thomas VC, Sadykov MR, Bose JL, Ahn DJ, Zimmerman MC, Bayles KW. The LysR-type transcriptional regulator, CidR, regulates stationary phase cell death in Staphylococcus aureus. Mol Microbiol 2016; 101:942-53. [PMID: 27253847 DOI: 10.1111/mmi.13433] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 11/29/2022]
Abstract
The Staphylococcus aureus LysR-type transcriptional regulator, CidR, activates the expression of two operons including cidABC and alsSD that display pro- and anti-death functions, respectively. Although several investigations have focused on the functions of different genes associated with these operons, the collective role of the CidR regulon in staphylococcal physiology is not clearly understood. Here we reveal that the primary role of this regulon is to limit acetate-dependent potentiation of cell death in staphylococcal populations. Although both CidB and CidC promote acetate generation and cell death, the CidR-dependent co-activation of CidA and AlsSD counters the effects of CidBC by redirecting intracellular carbon flux towards acetoin formation. From a mechanistic standpoint, we demonstrate that CidB is necessary for full activation of CidC, whereas CidA limits the abundance of CidC in the cell.
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Affiliation(s)
- Sujata S Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Vinai C Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Marat R Sadykov
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Jeffrey L Bose
- Department of Microbiology, Molecular Genetics and Immunology, The University of Kansas Medical Center, MSN 3029, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Daniel J Ahn
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Matthew C Zimmerman
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kenneth W Bayles
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA.
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23
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Yajjala VK, Thomas VC, Bauer C, Scherr TD, Fischer KJ, Fey PD, Bayles KW, Kielian T, Sun K. Resistance to Acute Macrophage Killing Promotes Airway Fitness of Prevalent Community-Acquired Staphylococcus aureus Strains. J Immunol 2016; 196:4196-203. [PMID: 27053759 DOI: 10.4049/jimmunol.1600081] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/13/2016] [Indexed: 11/19/2022]
Abstract
The incidence of methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in otherwise healthy individuals is increasing. To investigate the mechanism underlying the epidemiological success of predominant community-associated (CA)-MRSA strains, we examined their fitness traits during the initial interaction between bacteria and the host occurring in the lower airway. Using a mouse respiratory infection model, we show that clinical isolates often responsible for CA infections are highly resistant to clearance from healthy airways, whereas S. aureus strains not as prevalent or traditionally associated with hospital-associated infections are relatively susceptible. Mechanistically, the competitive fitness of S. aureus is a result of both agr-dependent and -independent resistance to innate bacterial killing. Furthermore, we show that rather than evasion from neutrophil-dependent bactericidal process, the observed S. aureus fitness in the lower airways is due to its intrinsic resistance to resident alveolar macrophage-mediated intracellular killing. Importantly, we demonstrate that the virulence determinants responsible for bacterial persistence in immune-competent mice are dispensable in mice with predisposing conditions such as influenza infection. Taken together, these novel findings of the improved competence of predominant CA-MRSA strains to survive innate killing in healthy hosts, particularly at the very beginning stage of infection, provide a unique insight into their epidemiological success.
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Affiliation(s)
- Vijaya Kumar Yajjala
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Vinai Chittezham Thomas
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Christopher Bauer
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Tyler D Scherr
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Karl J Fischer
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Tammy Kielian
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
| | - Keer Sun
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198
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24
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McCarthy H, Waters EM, Bose JL, Foster S, Bayles KW, O'Neill E, Fey PD, O'Gara JP. The major autolysin is redundant for Staphylococcus aureus USA300 LAC JE2 virulence in a murine device-related infection model. FEMS Microbiol Lett 2016; 363:fnw087. [PMID: 27044299 DOI: 10.1093/femsle/fnw087] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/31/2016] [Indexed: 12/14/2022] Open
Abstract
The major Staphylococcus aureus autolysin, Atl, has been implicated in attachment to surfaces and release of extracellular DNA during biofilm formation under laboratory conditions. Consistent with this, polyclonal antibodies to the amidase and glucosaminidase domains of Atl inhibited in vitro biofilm formation. However, in a murine model of device-related infection the community-associated S. aureus strain USA300 LAC JE2 established a successful infection in the absence of atl These data indicate that Atl activity is not required for biofilm production in this infection model and reveal the importance of characterizing the contribution of biofilm phenotypes to virulence under in vivo conditions.
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Affiliation(s)
- Hannah McCarthy
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Elaine M Waters
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Jeffrey L Bose
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Simon Foster
- Department of Molecular Biology and Biotechnology, The Krebs Institute, University of Sheffield, Sheffield S10 2TN, UK
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - Eoghan O'Neill
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland, Connolly Hospital, Dublin 15, Ireland
| | - Paul D Fey
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE 68198-5900, USA
| | - James P O'Gara
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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25
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Marshall DD, Sadykov MR, Thomas VC, Bayles KW, Powers R. Redox Imbalance Underlies the Fitness Defect Associated with Inactivation of the Pta-AckA Pathway in Staphylococcus aureus. J Proteome Res 2016; 15:1205-12. [PMID: 26975873 DOI: 10.1021/acs.jproteome.5b01089] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The phosphotransacetylase-acetate kinase (Pta-AckA) pathway is thought to be a vital ATP generating pathway for Staphylococcus aureus. Disruption of the Pta-AckA pathway during overflow metabolism causes significant reduction in growth rate and viability, albeit not due to intracellular ATP depletion. Here, we demonstrate that toxicity associated with inactivation of the Pta-AckA pathway resulted from an altered intracellular redox environment. Growth of the pta and ackA mutants under anaerobic conditions partially restored cell viability. NMR metabolomics analyses and (13)C6-glucose metabolism tracing experiments revealed the activity of multiple pathways that promote redox (NADH/NAD(+)) turnover to be enhanced in the pta and ackA mutants during anaerobic growth. Restoration of redox homeostasis in the pta mutant by overexpressing l- lactate dehydrogenase partially restored its viability under aerobic conditions. Together, our findings suggest that during overflow metabolism, the Pta-AckA pathway plays a critical role in preventing cell viability defects by promoting intracellular redox homeostasis.
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Affiliation(s)
- Darrell D Marshall
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
| | - Marat R Sadykov
- Department of Pathology and Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198, United States
| | - Vinai C Thomas
- Department of Pathology and Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198, United States
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center , Omaha, Nebraska 68198, United States
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln , Lincoln, Nebraska 68588, United States
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26
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Yajjala VK, Widhelm TJ, Endres JL, Fey PD, Bayles KW. Generation of a Transposon Mutant Library in Staphylococcus aureus and Staphylococcus epidermidis Using bursa aurealis. Methods Mol Biol 2016; 1373:103-110. [PMID: 25682373 DOI: 10.1007/7651_2014_189] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Transposon mutagenesis is a genetic process that involves the random insertion of transposons into a genome resulting in the disruption of function of the genes in which they insert. Identification of the insertion sites through DNA sequencing allows for the identification of the genes disrupted and the creation of "libraries" containing a collection of mutants in which a large number of the nonessential genes have been disrupted. These mutant libraries have been a great resource for investigators to understand the various biological functions of individual genes, including those involved in metabolism, antibiotic susceptibility, and pathogenesis. Here, we describe the detailed methodologies for constructing a sequence defined transposon mutant library in both Staphylococcus aureus and S. epidermidis using the mariner-based transposon, bursa aurealis.
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Affiliation(s)
- Vijaya Kumar Yajjala
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Todd J Widhelm
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jennifer L Endres
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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27
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Lewis AM, Matzdorf SS, Endres JL, Windham IH, Bayles KW, Rice KC. Examination of the Staphylococcus aureus nitric oxide reductase (saNOR) reveals its contribution to modulating intracellular NO levels and cellular respiration. Mol Microbiol 2015; 96:651-69. [PMID: 25651868 DOI: 10.1111/mmi.12962] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2015] [Indexed: 12/21/2022]
Abstract
Staphylococcus aureus nitrosative stress resistance is due in part to flavohemoprotein (Hmp). Although hmp is present in all sequenced S. aureus genomes, 37% of analyzed strains also contain nor, encoding a predicted quinol-type nitric oxide (NO) reductase (saNOR). DAF-FM staining of NO-challenged wild-type, nor, hmp and nor hmp mutant biofilms suggested that Hmp may have a greater contribution to intracellular NO detoxification relative to saNOR. However, saNOR still had a significant impact on intracellular NO levels and complemented NO detoxification in a nor hmp mutant. When grown as NO-challenged static (low-oxygen) cultures, hmp and nor hmp mutants both experienced a delay in growth initiation, whereas the nor mutant's ability to initiate growth was comparable with the wild-type strain. However, saNOR contributed to cell respiration in this assay once growth had resumed, as determined by membrane potential and respiratory activity assays. Expression of nor was upregulated during low-oxygen growth and dependent on SrrAB, a two-component system that regulates expression of respiration and nitrosative stress resistance genes. High-level nor promoter activity was also detectable in a cell subpopulation near the biofilm substratum. These results suggest that saNOR contributes to NO-dependent respiration during nitrosative stress, possibly conferring an advantage to nor+ strains in vivo.
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Affiliation(s)
- A M Lewis
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611-0700, USA
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28
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Lehman MK, Bose JL, Sharma-Kuinkel BK, Moormeier DE, Endres JL, Sadykov MR, Biswas I, Bayles KW. Identification of the amino acids essential for LytSR-mediated signal transduction in Staphylococcus aureus and their roles in biofilm-specific gene expression. Mol Microbiol 2015; 95:723-37. [PMID: 25491472 DOI: 10.1111/mmi.12902] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2014] [Indexed: 12/15/2022]
Abstract
Recent studies have demonstrated that expression of the Staphylococcus aureus lrgAB operon is specifically localized within tower structures during biofilm development. To gain a better understanding of the mechanisms underlying this spatial control of lrgAB expression, we carried out a detailed analysis of the LytSR two-component system. Specifically, a conserved aspartic acid (Asp53) of the LytR response regulator was shown to be the target of phosphorylation, which resulted in enhanced binding to the lrgAB promoter and activation of transcription. In addition, we identified His390 of the LytS histidine kinase as the site of autophosphorylation and Asn394 as a critical amino acid involved in phosphatase activity. Interestingly, LytS-independent activation of LytR was observed during planktonic growth, with acetyl phosphate acting as a phosphodonor to LytR. In contrast, mutations disrupting the function of LytS prevented tower-specific lrgAB expression, providing insight into the physiologic environment within these structures. In addition, overactivation of LytR led to increased lrgAB promoter activity during planktonic and biofilm growth and a change in biofilm morphology. Overall, the results of this study are the first to define the LytSR signal transduction pathway, as well as determine the metabolic context within biofilm tower structures that triggers these signaling events.
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Affiliation(s)
- McKenzie K Lehman
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
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29
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Thomas VC, Chaudhari SS, Jones J, Zimmerman MC, Bayles KW. Electron Paramagnetic Resonance (EPR) Spectroscopy to Detect Reactive Oxygen Species in Staphylococcus aureus. Bio Protoc 2015; 5:e1586. [PMID: 27182534 DOI: 10.21769/bioprotoc.1586] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Under aerobic conditions, Staphylococcus aureus (S. aureus) primarily metabolizes glucose to acetic acid. Although normally S. aureus is able to re-utilize acetate as a carbon source following glucose exhaustion, significantly high levels of acetate in the culture media may not only be growth inhibitory but also potentiates cell death in stationary phase cultures by a mechanism dependent on cytoplasmic acidification. One consequence of acetic acid toxicity is the production of reactive oxygen species (ROS). The present protocol describes the detection of ROS in S. aureus undergoing cell death by electron paramagnetic resonance (EPR) spectroscopy. Using 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CMH) as a cell permeable spin probe, we demonstrate the detection of various oxygen radicals generated by bacteria. Although standardized for S. aureus, the methods described here should be easily adapted for other bacterial species. This protocol is adapted from Thomas et al. (2014) and Thomas et al. (2010).
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Affiliation(s)
- Vinai Chittezham Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, USA
| | - Sujata S Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, USA
| | - Jocelyn Jones
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, USA
| | - Matthew C Zimmerman
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, USA
| | - Kenneth W Bayles
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, USA
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30
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Wang G, Hanke ML, Mishra B, Lushnikova T, Heim C, Chittezham Thomas V, Bayles KW, Kielian T. Transformation of human cathelicidin LL-37 into selective, stable, and potent antimicrobial compounds. ACS Chem Biol 2014; 9:1997-2002. [PMID: 25061850 PMCID: PMC4168778 DOI: 10.1021/cb500475y] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 07/25/2014] [Indexed: 01/26/2023]
Abstract
This Letter reports a family of novel antimicrobial compounds obtained by combining peptide library screening with structure-based design. Library screening led to the identification of a human LL-37 peptide resistant to chymotrypsin. This d-amino-acid-containing peptide template was active against Escherichia coli but not methicillin-resistant Staphylococcus aureus (MRSA). It possesses a unique nonclassic amphipathic structure with hydrophobic defects. By repairing the hydrophobic defects, the peptide (17BIPHE2) gained activity against the ESKAPE pathogens, including Enterococcus faecium, S. aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacter species. In vitro, 17BIPHE2 could disrupt bacterial membranes and bind to DNA. In vivo, the peptide prevented staphylococcal biofilm formation in a mouse model of catheter-associated infection. Meanwhile, it boosted the innate immune response to further combat the infection. Because these peptides are potent, cell-selective, and stable to several proteases, they may be utilized to combat one or more ESKAPE pathogens.
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Affiliation(s)
- Guangshun Wang
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, Nebraska 68198-6495, United States
| | - Mark L. Hanke
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 985900 Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Biswajit Mishra
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, Nebraska 68198-6495, United States
| | - Tamara Lushnikova
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, Nebraska 68198-6495, United States
| | - Cortney
E. Heim
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 985900 Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Vinai Chittezham Thomas
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 985900 Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Kenneth W. Bayles
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 985900 Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
| | - Tammy Kielian
- Department
of Pathology and Microbiology, University
of Nebraska Medical Center, 985900 Nebraska Medical Center, Omaha, Nebraska 68198-5900, United States
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31
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Thomas VC, Sadykov MR, Chaudhari SS, Jones J, Endres JL, Widhelm TJ, Ahn JS, Jawa RS, Zimmerman MC, Bayles KW. A central role for carbon-overflow pathways in the modulation of bacterial cell death. PLoS Pathog 2014; 10:e1004205. [PMID: 24945831 PMCID: PMC4063974 DOI: 10.1371/journal.ppat.1004205] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/08/2014] [Indexed: 12/17/2022] Open
Abstract
Similar to developmental programs in eukaryotes, the death of a subpopulation of cells is thought to benefit bacterial biofilm development. However mechanisms that mediate a tight control over cell death are not clearly understood at the population level. Here we reveal that CidR dependent pyruvate oxidase (CidC) and α-acetolactate synthase/decarboxylase (AlsSD) overflow metabolic pathways, which are active during staphylococcal biofilm development, modulate cell death to achieve optimal biofilm biomass. Whereas acetate derived from CidC activity potentiates cell death in cells by a mechanism dependent on intracellular acidification and respiratory inhibition, AlsSD activity effectively counters CidC action by diverting carbon flux towards neutral rather than acidic byproducts and consuming intracellular protons in the process. Furthermore, the physiological features that accompany metabolic activation of cell death bears remarkable similarities to hallmarks of eukaryotic programmed cell death, including the generation of reactive oxygen species and DNA damage. Finally, we demonstrate that the metabolic modulation of cell death not only affects biofilm development but also biofilm-dependent disease outcomes. Given the ubiquity of such carbon overflow pathways in diverse bacterial species, we propose that the metabolic control of cell death may be a fundamental feature of prokaryotic development. Many bacterial species including the pathogen Staphylococcus aureus are capable of adhering to surfaces and forming complex communities called biofilms. This mode of growth can be particularly challenging from an infection control standpoint, as they are often refractory to antibiotics and host immune system. Although developmental processes underlying biofilm formation are not entirely clear, recent evidence suggests that cell death of a subpopulation is crucial for its maturation. In this study we provide insight regarding the metabolic pathways that control cell death and demonstrate that acetate, a by-product of glucose catabolism, potentiates a form of cell death that exhibits physiological and biochemical hallmarks of apoptosis in eukaryotic organisms. Finally, we demonstrate that altering the ability of metabolic pathways that regulate acetate mediated cell death in S. aureus affects the outcome of biofilm-related diseases, such as infective endocarditis.
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Affiliation(s)
- Vinai Chittezham Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Marat R. Sadykov
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Sujata S. Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Joselyn Jones
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jennifer L. Endres
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Todd J. Widhelm
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jong-Sam Ahn
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Randeep S. Jawa
- Department of Surgery, Stony Brook University School of Medicine, Stony Brook, New York, United States of America
| | - Matthew C. Zimmerman
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kenneth W. Bayles
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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32
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Abstract
A common in vitro method to study Staphylococcus epidermidis biofilm development is to allow the bacteria to attach and grow on a solid surface in the presence of a continuous flow of nutrients. Under these conditions, the bacteria progress through a series of developmental steps, ultimately forming a multicellular structure containing differentiated cell populations. The observation of the biofilm at various time-points throughout this process provides a glimpse of the temporal changes that occur. Furthermore, use of metabolic stains and fluorescent reporters provides insight into the physiologic and transcriptional changes that occur within a developing biofilm. Currently, there are multiple systems available to assess biofilm development, each with advantages and disadvantages depending on the questions being asked. In this chapter, we describe the use of two separate flow-cell systems used to evaluate the developmental characteristics of staphylococcal biofilms: the FC270 flow-cell system from BioSurface Technologies, Corp. and the BioFlux1000 microfluidic flow-cell system from Fluxion Bioscience, Inc.
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Affiliation(s)
- Derek E Moormeier
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, USA
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Laabei M, Recker M, Rudkin JK, Aldeljawi M, Gulay Z, Sloan TJ, Williams P, Endres JL, Bayles KW, Fey PD, Yajjala VK, Widhelm T, Hawkins E, Lewis K, Parfett S, Scowen L, Peacock SJ, Holden M, Wilson D, Read TD, van den Elsen J, Priest NK, Feil EJ, Hurst LD, Josefsson E, Massey RC. Predicting the virulence of MRSA from its genome sequence. Genome Res 2014; 24:839-49. [PMID: 24717264 PMCID: PMC4009613 DOI: 10.1101/gr.165415.113] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Microbial virulence is a complex and often multifactorial phenotype, intricately linked to a pathogen’s evolutionary trajectory. Toxicity, the ability to destroy host cell membranes, and adhesion, the ability to adhere to human tissues, are the major virulence factors of many bacterial pathogens, including Staphylococcus aureus. Here, we assayed the toxicity and adhesiveness of 90 MRSA (methicillin resistant S. aureus) isolates and found that while there was remarkably little variation in adhesion, toxicity varied by over an order of magnitude between isolates, suggesting different evolutionary selection pressures acting on these two traits. We performed a genome-wide association study (GWAS) and identified a large number of loci, as well as a putative network of epistatically interacting loci, that significantly associated with toxicity. Despite this apparent complexity in toxicity regulation, a predictive model based on a set of significant single nucleotide polymorphisms (SNPs) and insertion and deletions events (indels) showed a high degree of accuracy in predicting an isolate’s toxicity solely from the genetic signature at these sites. Our results thus highlight the potential of using sequence data to determine clinically relevant parameters and have further implications for understanding the microbial virulence of this opportunistic pathogen.
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Affiliation(s)
- Maisem Laabei
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom
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Abdelhady W, Bayer AS, Seidl K, Moormeier DE, Bayles KW, Cheung A, Yeaman MR, Xiong YQ. Impact of vancomycin on sarA-mediated biofilm formation: role in persistent endovascular infections due to methicillin-resistant Staphylococcus aureus. J Infect Dis 2014; 209:1231-40. [PMID: 24403556 DOI: 10.1093/infdis/jiu007] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Staphylococcus aureus is the most common cause of endovascular infections. The staphylococcal accessory regulator A locus (sarA) is a major virulence determinant that may potentially impact methicillin-resistant S. aureus (MRSA) persistence in such infections via its influence on biofilm formation. METHODS Two healthcare-associated MRSA isolates from patients with persistent bacteremia and 2 prototypical community-acquired MRSA strains, as well as their respective isogenic sarA mutants, were studied for in vitro biofilm formation, fibronectin-binding capacity, autolysis, and protease and nuclease activities. These assays were done in the presence or absence of sub-minimum inhibitory concentrations (MICs) of vancomycin. In addition, these strain pairs were compared for intrinsic virulence and responses to vancomycin therapy in experimental infective endocarditis, a prototypical biofilm model. RESULTS All sarA mutants displayed significantly reduced biofilm formation and binding to fibronectin but increased protease production in vitro, compared with their respective parental strains. Interestingly, exposure to sub-MICs of vancomycin significantly promoted biofilm formation and fibronectin-binding in parental strains but not in sarA mutants. In addition, all sarA mutants became exquisitely susceptible to vancomycin therapy, compared with their respective parental strains, in the infective endocarditis model. CONCLUSIONS These observations suggest that sarA activation is important in persistent MRSA endovascular infection, potentially in the setting of biofilm formation.
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Affiliation(s)
- Wessam Abdelhady
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance
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35
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Abstract
Methods used to understand the function of a gene/protein are one of the hallmarks of modern molecular genetics. The ability to genetically manipulate bacteria has become a fundamental tool in studying these organisms and while basic cloning has become a routine task in molecular biology laboratories, generating directed mutations can be a daunting task. This chapter describes the method of allelic exchange in Staphylococcus aureus using temperature-sensitive plasmids that have successfully produced a variety of chromosomal mutations, including in-frame deletions, insertion of antibiotic-resistance cassettes, and even single-nucleotide point mutations.
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Affiliation(s)
- McKenzie K Lehman
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jeffrey L Bose
- Department of Microbiology, Molecular Genetics and Immunology, The University of Kansas Medical Center, MSN 3029, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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Widhelm TJ, Yajjala VK, Endres JL, Fey PD, Bayles KW. Methods to generate a sequence-defined transposon mutant library in Staphylococcus epidermidis strain 1457. Methods Mol Biol 2014; 1106:135-42. [PMID: 24222462 DOI: 10.1007/978-1-62703-736-5_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transposon mutant libraries are valuable resources to investigators studying bacterial species, including Staphylococcus epidermidis, which are difficult to genetically manipulate. Although sequence-defined transposon mutant libraries have been constructed in Staphylococcus aureus, no such library exists for S. epidermidis. Nevertheless, the study of Tn917-mediated mutations has been paramount in discovering unique aspects of S. epidermidis biology including initial adherence and accumulation during biofilm formation. Herein, we describe modifications to the methodology first described by Bae et al. to utilize the mariner-based transposon bursa aurealis to generate mutants in S. epidermidis strain 1457.
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Affiliation(s)
- Todd J Widhelm
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, NE, USA
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Gries CM, Bose JL, Nuxoll AS, Fey PD, Bayles KW. The Ktr potassium transport system in Staphylococcus aureus and its role in cell physiology, antimicrobial resistance and pathogenesis. Mol Microbiol 2013; 89:760-73. [PMID: 23815639 DOI: 10.1111/mmi.12312] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2013] [Indexed: 02/05/2023]
Abstract
Potassium (K(+) ) plays a vital role in bacterial physiology, including regulation of cytoplasmic pH, turgor pressure and transmembrane electrical potential. Here, we examine the Staphylococcus aureus Ktr system uniquely comprised of two ion-conducting proteins (KtrB and KtrD) and only one regulator (KtrA). Growth of Ktr system mutants was severely inhibited under K(+) limitation, yet detectable after an extended lag phase, indicating the presence of a secondary K(+) transporter. Disruption of both ktrA and the Kdp-ATPase system, important for K(+) uptake in other organisms, eliminated regrowth in 0.1 mM K(+) , demonstrating a compensatory role for Kdp to the Ktr system. Consistent with K(+) transport mutations, S. aureus devoid of the Ktr system became sensitive to hyperosmotic conditions, exhibited a hyperpolarized plasma membrane, and increased susceptibility to aminoglycoside antibiotics and cationic antimicrobials. In contrast to other organisms, the S. aureus Ktr system was shown to be important for low-K(+) growth under alkaline conditions, but played only a minor role in neutral and acidic conditions. In a mouse competitive index model of bacteraemia, the ktrA mutant was significantly outcompeted by the parental strain. Combined, these results demonstrate a primary mechanism of K(+) uptake in S. aureus and a role for this system in pathogenesis.
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Affiliation(s)
- Casey M Gries
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
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Wang J, Bayles KW. Programmed cell death in plants: lessons from bacteria? Trends Plant Sci 2013; 18:133-139. [PMID: 23083702 PMCID: PMC3556228 DOI: 10.1016/j.tplants.2012.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/10/2012] [Accepted: 09/13/2012] [Indexed: 05/29/2023]
Abstract
Programmed cell death (PCD) has well-established roles in the development and physiology of animals, plants, and fungi. Although aspects of PCD control appear evolutionarily conserved between these organisms, the extent of conservation remains controversial. Recently, a putative bacterial PCD protein homolog in plants was found to play a significant role in cell death control, indicating a conservation of function between these highly divergent organisms. Interestingly, these bacterial proteins are thought to be evolutionarily linked to the Bcl-2 family of proteins. In this opinion article, we propose a new unifying model to describe the relationship between bacterial and plant PCD systems and propose that the underlying control of PCD is conserved across at least three Kingdoms of life.
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Affiliation(s)
- Junhui Wang
- Institute of Genetics, College of Life Sciences, Zhejiang University, Zijingang Campus, Hangzhou 310058, China
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Nuxoll AS, Halouska SM, Sadykov MR, Hanke ML, Bayles KW, Kielian T, Powers R, Fey PD. CcpA regulates arginine biosynthesis in Staphylococcus aureus through repression of proline catabolism. PLoS Pathog 2012; 8:e1003033. [PMID: 23209408 PMCID: PMC3510247 DOI: 10.1371/journal.ppat.1003033] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Accepted: 10/01/2012] [Indexed: 12/19/2022] Open
Abstract
Staphylococcus aureus is a leading cause of community-associated and nosocomial infections. Imperative to the success of S. aureus is the ability to adapt and utilize nutrients that are readily available. Genomic sequencing suggests that S. aureus has the genes required for synthesis of all twenty amino acids. However, in vitro experimentation demonstrates that staphylococci have multiple amino acid auxotrophies, including arginine. Although S. aureus possesses the highly conserved anabolic pathway that synthesizes arginine via glutamate, we demonstrate here that inactivation of ccpA facilitates the synthesis of arginine via the urea cycle utilizing proline as a substrate. Mutations within putA, rocD, arcB1, argG and argH abolished the ability of S. aureus JE2 ccpA::tetL to grow in the absence of arginine, whereas an interruption in argJBCF, arcB2, or proC had no effect. Furthermore, nuclear magnetic resonance demonstrated that JE2 ccpA::ermB produced 13C5 labeled arginine when grown with 13C5 proline. Taken together, these data support the conclusion that S. aureus synthesizes arginine from proline during growth on secondary carbon sources. Furthermore, although highly conserved in all sequenced S. aureus genomes, the arginine anabolic pathway (ArgJBCDFGH) is not functional under in vitro growth conditions. Finally, a mutation in argH attenuated virulence in a mouse kidney abscess model in comparison to wild type JE2 demonstrating the importance of arginine biosynthesis in vivo via the urea cycle. However, mutations in argB, argF, and putA did not attenuate virulence suggesting both the glutamate and proline pathways are active and they, or their pathway intermediates, can complement each other in vivo. Although Staphylococcus aureus encodes the highly conserved arginine biosynthesis pathway via glutamate, arginine is an essential amino acid. We found that a mutation in ccpA, a gene encoding a protein facilitating carbon catabolite repression, mediates arginine biosynthesis under in vitro growth conditions. However, both genetic and biochemical evidence suggested that a S. aureus ccpA mutant synthesizes arginine via proline and the urea cycle, a pathway not demonstrated in bacteria before. Furthermore, an animal model of S. aureus infection demonstrated the importance of arginine biosynthesis in vivo. This new pathway sheds light on important host-pathogen interactions and suggests S. aureus has evolved to address arginine depletion in the host by synthesizing arginine from a readily available substrate such as proline.
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Affiliation(s)
- Austin S. Nuxoll
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Steven M. Halouska
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Marat R. Sadykov
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Mark L. Hanke
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Tammy Kielian
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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40
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Bose JL, Lehman MK, Fey PD, Bayles KW. Contribution of the Staphylococcus aureus Atl AM and GL murein hydrolase activities in cell division, autolysis, and biofilm formation. PLoS One 2012; 7:e42244. [PMID: 22860095 PMCID: PMC3409170 DOI: 10.1371/journal.pone.0042244] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 07/02/2012] [Indexed: 11/21/2022] Open
Abstract
The most prominent murein hydrolase of Staphylococcus aureus, AtlA, is a bifunctional enzyme that undergoes proteolytic cleavage to yield two catalytically active proteins, an amidase (AM) and a glucosaminidase (GL). Although the bifunctional nature of AtlA has long been recognized, most studies have focused on the combined functions of this protein in cell wall metabolism and biofilm development. In this study, we generated mutant derivatives of the clinical S. aureus isolate, UAMS-1, in which one or both of the AM and GL domains of AtlA have been deleted. Examination of these strains revealed that each mutant exhibited growth rates comparable to the parental strain, but showed clumping phenotypes and lysis profiles that were distinct from the parental strain and each other, suggesting distinct roles in cell wall metabolism. Given the known function of autolysis in the release of genomic DNA for use as a biofilm matrix molecule, we also tested the mutants in biofilm assays and found both AM and GL necessary for biofilm development. Furthermore, the use of enzymatically inactive point mutations revealed that both AM and GL must be catalytically active for S. aureus to form a biofilm. The results of this study provide insight into the relative contributions of AM and GL in S. aureus and demonstrate the contribution of Atl-mediated lysis in biofilm development.
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Affiliation(s)
- Jeffrey L. Bose
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - McKenzie K. Lehman
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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41
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Liu XM, Zhang Y, Chen F, Khutsishvili I, Fehringer EV, Marky LA, Bayles KW, Wang D. Prevention of orthopedic device-associated osteomyelitis using oxacillin-containing biomineral-binding liposomes. Pharm Res 2012; 29:3169-79. [PMID: 22733150 DOI: 10.1007/s11095-012-0812-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/21/2012] [Indexed: 12/19/2022]
Abstract
PURPOSE To develop novel biomineral-binding liposomes (BBL) for the prevention of orthopedic implant associated osteomyelitis. METHODS A biomineral-binding lipid, alendronate-tri(ethyleneglycol)-cholesterol conjugate (ALN-TEG-Chol), was synthesized through Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition (a versatile click reaction). Mixing with other excipients, the new lipid was used to develop BBL. Thermodynamic behavior was studied by differential scanning calorimetry (DSC). In vitro biomineral-binding potential and kinetics were evaluated on hydroxyapatite (HA, a widely used material for orthopedic implant devices) particles. Oxacillin was encapsulated into BBL and used for in vitro evaluation in preventing Staphylococcus aureus biofilm formation. RESULTS DSC analysis showed that ALN-TEG-Chol could inhibit the phase transition of liposomes by reducing its cooperativity, yielding liposomes with thermodynamic stability similar to liposomes containing regular cholesterol. BBL showed fast and strong binding ability to HA. Oxacillin-loading BBL demonstrated significantly better preventive efficacy against bacteria colonization when challenged with S. aureus isolate, implying its potential in preventing orthopedic implant associated osteomyelitis. CONCLUSIONS In this proof of concept study, novel BBL has been successfully developed and validated for reducing the frequency of implantable device-related infections.
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Affiliation(s)
- Xin-Ming Liu
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, COP 3026, Omaha, NE 68198-6025, USA
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42
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Kiedrowski MR, Kavanaugh JS, Malone CL, Mootz JM, Voyich JM, Smeltzer MS, Bayles KW, Horswill AR. Nuclease modulates biofilm formation in community-associated methicillin-resistant Staphylococcus aureus. PLoS One 2011; 6:e26714. [PMID: 22096493 PMCID: PMC3214024 DOI: 10.1371/journal.pone.0026714] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Accepted: 10/03/2011] [Indexed: 12/13/2022] Open
Abstract
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) is an emerging contributor to biofilm-related infections. We recently reported that strains lacking sigma factor B (sigB) in the USA300 lineage of CA-MRSA are unable to develop a biofilm. Interestingly, when spent media from a USA300 sigB mutant was incubated with other S. aureus strains, biofilm formation was inhibited. Following fractionation and mass spectrometry analysis, the major anti-biofilm factor identified in the spent media was secreted thermonuclease (Nuc). Considering reports that extracellular DNA (eDNA) is an important component of the biofilm matrix, we investigated the regulation and role of Nuc in USA300. The expression of the nuc gene was increased in a sigB mutant, repressed by glucose supplementation, and was unaffected by the agr quorum-sensing system. A FRET assay for Nuc activity was developed and confirmed the regulatory results. A USA300 nuc mutant was constructed and displayed an enhanced biofilm-forming capacity, and the nuc mutant also accumulated more high molecular weight eDNA than the WT and regulatory mutant strains. Inactivation of nuc in the USA300 sigB mutant background partially repaired the sigB biofilm-negative phenotype, suggesting that nuc expression contributes to the inability of the mutant to form biofilm. To test the generality of the nuc mutant biofilm phenotypes, the mutation was introduced into other S. aureus genetic backgrounds and similar increases in biofilm formation were observed. Finally, using multiple S. aureus strains and regulatory mutants, an inverse correlation between Nuc activity and biofilm formation was demonstrated. Altogether, our findings confirm the important role for eDNA in the S. aureus biofilm matrix and indicates Nuc is a regulator of biofilm formation.
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Affiliation(s)
- Megan R. Kiedrowski
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jeffrey S. Kavanaugh
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Cheryl L. Malone
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Joe M. Mootz
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Jovanka M. Voyich
- Department of Veterinary Microbiology, Montana State University, Bozeman, Montana, United States of America
| | - Mark S. Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Kenneth W. Bayles
- Department of Pathology, Nebraska Medical Center, University of Nebraska, Omaha, Nebraska, United States of America
| | - Alexander R. Horswill
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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Pang X, Moussa SH, Targy NM, Bose JL, George NM, Gries C, Lopez H, Zhang L, Bayles KW, Young R, Luo X. Active Bax and Bak are functional holins. Genes Dev 2011; 25:2278-90. [PMID: 22006182 DOI: 10.1101/gad.171645.111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The mechanism of Bax/Bak-dependent mitochondrial outer membrane permeabilization (MOMP), a central apoptotic event primarily controlled by the Bcl-2 family proteins, remains not well understood. Here, we express active Bax/Bak in bacteria, the putative origin of mitochondria, and examine their functional similarities to the λ bacteriophage (λ) holin. As critical effectors for bacterial lysis, holin oligomers form membrane lesions, through which endolysin, a muralytic enzyme, escapes the cytoplasm to attack the cell wall at the end of the infection cycle. We found that active Bax/Bak, but not any other Bcl-2 family protein, displays holin behavior, causing bacterial lysis by releasing endolysin in an oligomerization-dependent manner. Strikingly, replacing the holin gene with active alleles of Bax/Bak results in plaque-forming phages. Furthermore, we provide evidence that active Bax produces large membrane holes, the size of which is controlled by structural elements of Bax. Notably, lysis by active Bax is inhibited by Bcl-xL, and the lysis activity of the wild-type Bax is stimulated by a BH3-only protein. Together, these results mechanistically link MOMP to holin-mediated hole formation in the bacterial plasma membrane.
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Affiliation(s)
- Xiaming Pang
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, USA
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Thurlow LR, Hanke ML, Fritz T, Angle A, Aldrich A, Williams SH, Engebretsen IL, Bayles KW, Horswill AR, Kielian T. Staphylococcus aureus biofilms prevent macrophage phagocytosis and attenuate inflammation in vivo. J Immunol 2011; 186:6585-96. [PMID: 21525381 DOI: 10.4049/jimmunol.1002794] [Citation(s) in RCA: 454] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Biofilms are complex communities of bacteria encased in a matrix composed primarily of polysaccharides, extracellular DNA, and protein. Staphylococcus aureus can form biofilm infections, which are often debilitating due to their chronicity and recalcitrance to antibiotic therapy. Currently, the immune mechanisms elicited during biofilm growth and their impact on bacterial clearance remain to be defined. We used a mouse model of catheter-associated biofilm infection to assess the functional importance of TLR2 and TLR9 in the host immune response during biofilm formation, because ligands for both receptors are present within the biofilm. Interestingly, neither TLR2 nor TLR9 impacted bacterial density or inflammatory mediator secretion during biofilm growth in vivo, suggesting that S. aureus biofilms circumvent these traditional bacterial recognition pathways. Several potential mechanisms were identified to account for biofilm evasion of innate immunity, including significant reductions in IL-1β, TNF-α, CXCL2, and CCL2 expression during biofilm infection compared with the wound healing response elicited by sterile catheters, limited macrophage invasion into biofilms in vivo, and a skewing of the immune response away from a microbicidal phenotype as evidenced by decreases in inducible NO synthase expression concomitant with robust arginase-1 induction. Coculture studies of macrophages with S. aureus biofilms in vitro revealed that macrophages successful at biofilm invasion displayed limited phagocytosis and gene expression patterns reminiscent of alternatively activated M2 macrophages. Collectively, these findings demonstrate that S. aureus biofilms are capable of attenuating traditional host proinflammatory responses, which may explain why biofilm infections persist in an immunocompetent host.
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Affiliation(s)
- Lance R Thurlow
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Ahn SJ, Rice KC, Oleas J, Bayles KW, Burne RA. The Streptococcus mutans Cid and Lrg systems modulate virulence traits in response to multiple environmental signals. Microbiology (Reading) 2010; 156:3136-3147. [PMID: 20671018 PMCID: PMC3068699 DOI: 10.1099/mic.0.039586-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The tight control of autolysis by Streptococcus mutans is critical for proper virulence gene expression and biofilm formation. A pair of dicistronic operons, SMU.575/574 (lrgAB) and SMU.1701/1700 (designated cidAB), encode putative membrane proteins that share structural features with the bacteriophage-encoded holin family of proteins, which modulate host cell lysis during lytic infection. Analysis of S. mutans lrg and cid mutants revealed a role for these operons in autolysis, biofilm formation, glucosyltransferase expression and oxidative stress tolerance. Expression of lrgAB was repressed during early exponential phase and was induced over 1000-fold as cells entered late exponential phase, whereas cidAB expression declined from early to late exponential phase. A two-component system encoded immediately upstream of lrgAB (LytST) was required for activation of lrgAB expression, but not for cid expression. In addition to availability of oxygen, glucose levels were revealed to affect lrg and cid transcription differentially and significantly, probably through CcpA (carbon catabolite protein A). Collectively, these findings demonstrate that the Cid/Lrg system can affect several virulence traits of S. mutans, and its expression is controlled by two major environmental signals, oxygen and glucose. Moreover, cid/lrg expression is tightly regulated by LytST and CcpA.
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Affiliation(s)
- Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
| | - Kelly C. Rice
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Janneth Oleas
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, FL 32610, USA
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Robert A. Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL 32610, USA
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Beenken KE, Mrak LN, Griffin LM, Zielinska AK, Shaw LN, Rice KC, Horswill AR, Bayles KW, Smeltzer MS. Epistatic relationships between sarA and agr in Staphylococcus aureus biofilm formation. PLoS One 2010; 5:e10790. [PMID: 20520723 PMCID: PMC2875390 DOI: 10.1371/journal.pone.0010790] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 04/30/2010] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The accessory gene regulator (agr) and staphylococcal accessory regulator (sarA) play opposing roles in Staphylococcus aureus biofilm formation. There is mounting evidence to suggest that these opposing roles are therapeutically relevant in that mutation of agr results in increased biofilm formation and decreased antibiotic susceptibility while mutation of sarA has the opposite effect. To the extent that induction of agr or inhibition of sarA could potentially be used to limit biofilm formation, this makes it important to understand the epistatic relationships between these two loci. METHODOLOGY/PRINCIPAL FINDINGS We generated isogenic sarA and agr mutants in clinical isolates of S. aureus and assessed the relative impact on biofilm formation. Mutation of agr resulted in an increased capacity to form a biofilm in the 8325-4 laboratory strain RN6390 but had little impact in clinical isolates S. aureus. In contrast, mutation of sarA resulted in a reduced capacity to form a biofilm in all clinical isolates irrespective of the functional status of agr. This suggests that the regulatory role of sarA in biofilm formation is independent of the interaction between sarA and agr and that sarA is epistatic to agr in this context. This was confirmed by demonstrating that restoration of sarA function restored the ability to form a biofilm even in the corresponding agr mutants. Mutation of sarA in clinical isolates also resulted in increased production of extracellular proteases and extracellular nucleases, both of which contributed to the biofilm-deficient phenotype of sarA mutants. However, studies comparing different strains with and without proteases inhibitors and/or mutation of the nuclease genes demonstrated that the agr-independent, sarA-mediated repression of extracellular proteases plays a primary role in this regard. CONCLUSIONS AND SIGNIFICANCE The results we report suggest that inhibitors of sarA-mediated regulation could be used to limit biofilm formation in S. aureus and that the efficacy of such inhibitors would not be limited by spontaneous mutation of agr in the human host.
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Affiliation(s)
- Karen E. Beenken
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Lara N. Mrak
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Linda M. Griffin
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Agnieszka K. Zielinska
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Lindsey N. Shaw
- Department of Biology, University of South Florida, Tampa, Florida, United States of America
| | - Kelly C. Rice
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Alexander R. Horswill
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Kenneth W. Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Mark S. Smeltzer
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
- * E-mail:
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Chen F, Rice KC, Liu XM, Reinhardt RA, Bayles KW, Wang D. Triclosan-loaded tooth-binding micelles for prevention and treatment of dental biofilm. Pharm Res 2010; 27:2356-64. [PMID: 20387099 DOI: 10.1007/s11095-010-0119-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Accepted: 03/05/2010] [Indexed: 11/29/2022]
Abstract
PURPOSE To develop tooth-binding micelle formulations of triclosan for the prevention and treatment of dental caries. METHODS Alendronate (ALN) was conjugated to the chain termini of different Pluronic copolymers to confer tooth-binding ability to the micelles. Using 3 different formulation methods, Pluronics and ALN-modified Pluronics were used to prepare triclosan-loaded tooth-binding micelles. The formulation parameters were optimized for triclosan solubility, particle size, hydroxyapatite (HA) binding capability and in vitro drug release profile. The optimized formulation was tested on an in vitro biofilm model. RESULTS Direct dissolution was selected as the best formulation method. Triclosan-loaded tooth-binding micelles were able to inhibit initial biofilm growth of Streptococcus mutans UA159 by 6-log CFU/HA disc compared to the untreated control. These tooth-binding micelles were also able to reduce the viability of preformed biofilm by 4-log CFU/HA disc compared to the untreated control. CONCLUSIONS Triclosan-loaded tooth-binding micelle formulations have been successfully developed and optimized in this study. These micelle formulations demonstrated promising anti-cariogenic bacteria capabilities and may find applications in the prevention and treatment of dental caries.
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Affiliation(s)
- Fu Chen
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska 68198-6025, USA
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Weaver KE, Reddy SG, Brinkman CL, Patel S, Bayles KW, Endres JL. Identification and characterization of a family of toxin-antitoxin systems related to the Enterococcus faecalis plasmid pAD1 par addiction module. Microbiology (Reading) 2009; 155:2930-2940. [PMID: 19542006 DOI: 10.1099/mic.0.030932-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The par locus of the Enterococcus faecalis plasmid pAD1 is an RNA-regulated addiction module encoding the peptide toxin Fst. Homology searches revealed that Fst belongs to a family of at least nine related peptides encoded on the chromosomes and plasmids of six different Gram-positive bacterial species. Comparison of an alignment of these peptides with the results of a saturation mutagenesis analysis indicated regions of the peptides important for biological function. Examination of the genetic context of the fst genes revealed that all of these peptides are encoded within par-like loci with conserved features similar to pAD1 par. All four Ent. faecalis family members were demonstrated to produce the expected toxin-encoding and regulatory RNA products. The locus from the Ent. faecalis plasmid pAMS1 was demonstrated to function as an addiction module and Fst was shown to be toxic to Staphylococcus aureus, suggesting that a plasmid-encoded module in that species is performing the same function. Thus, the pAD1-encoded par locus appears to be the prototype of a family of related loci found in several Gram-positive species.
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Affiliation(s)
- Keith E Weaver
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Shirisha G Reddy
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Cassandra L Brinkman
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Smita Patel
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Kenneth W Bayles
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Jennifer L Endres
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Mann EE, Rice KC, Boles BR, Endres JL, Ranjit D, Chandramohan L, Tsang LH, Smeltzer MS, Horswill AR, Bayles KW. Modulation of eDNA release and degradation affects Staphylococcus aureus biofilm maturation. PLoS One 2009; 4:e5822. [PMID: 19513119 PMCID: PMC2688759 DOI: 10.1371/journal.pone.0005822] [Citation(s) in RCA: 349] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 05/12/2009] [Indexed: 12/16/2022] Open
Abstract
Recent studies have demonstrated a role for Staphylococcus aureus cidA-mediated cell lysis and genomic DNA release in biofilm adherence. The current study extends these findings by examining both temporal and additional genetic factors involved in the control of genomic DNA release and degradation during biofilm maturation. Cell lysis and DNA release were found to be critical for biofilm attachment during the initial stages of development and the released DNA (eDNA) remained an important matrix component during biofilm maturation. This study also revealed that an lrgAB mutant exhibits increased biofilm adherence and matrix-associated eDNA consistent with its proposed role as an inhibitor of cidA-mediated lysis. In flow-cell assays, both cid and lrg mutations had dramatic effects on biofilm maturation and tower formation. Finally, staphylococcal thermonuclease was shown to be involved in biofilm development as a nuc mutant formed a thicker biofilm containing increased levels of matrix-associated eDNA. Together, these findings suggest a model in which the opposing activities of the cid and lrg gene products control cell lysis and genomic DNA release during biofilm development, while staphylococcal thermonuclease functions to degrade the eDNA, possibly as a means to promote biofilm dispersal.
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Affiliation(s)
- Ethan E. Mann
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kelly C. Rice
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, United States of America
| | - Blaise R. Boles
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Jennifer L. Endres
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Dev Ranjit
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lakshmi Chandramohan
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Laura H. Tsang
- Department of Microbiology & Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Mark S. Smeltzer
- Department of Microbiology & Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States of America
| | - Alexander R. Horswill
- Department of Microbiology, University of Iowa, Iowa City, Iowa, United States of America
| | - Kenneth W. Bayles
- Department of Pathology & Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Abstract
Many successful pathogens have developed the ability to adhere to and invade animal tissues. Recent experimental evidence suggests that S. aureus, generally perceived as an extracellular pathogen, can also invade and, in some cases, multiply within host cells. As a proxy to infections in animal hosts, the study of S. aureus interactions with tissue culture cells has become an important research tool in many aspects of bacterial pathogenesis. In this unit, we describe two cell culture models, including bovine mammary epithelial cells and human umbilical vein endothelial cells, that investigators have used to study the interactions of S. aureus with host cells.
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