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Berkowitz RL, Bluhm AP, Knox GW, McCurdy CR, Ostrov DA, Norris MH. Sigma Receptor Ligands Prevent COVID Mortality In Vivo: Implications for Future Therapeutics. Int J Mol Sci 2023; 24:15718. [PMID: 37958703 PMCID: PMC10647780 DOI: 10.3390/ijms242115718] [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: 09/26/2023] [Revised: 10/26/2023] [Accepted: 10/28/2023] [Indexed: 11/15/2023] Open
Abstract
The emergence of lethal coronaviruses follows a periodic pattern which suggests a recurring cycle of outbreaks. It remains uncertain as to when the next lethal coronavirus will emerge, though its eventual emergence appears to be inevitable. New mutations in evolving SARS-CoV-2 variants have provided resistance to current antiviral drugs, monoclonal antibodies, and vaccines, reducing their therapeutic efficacy. This underscores the urgent need to investigate alternative therapeutic approaches. Sigma receptors have been unexpectedly linked to the SARS-CoV-2 life cycle due to the direct antiviral effect of their ligands. Coronavirus-induced cell stress facilitates the formation of an ER-derived complex conducive to its replication. Sigma receptor ligands are believed to prevent the formation of this complex. Repurposing FDA-approved drugs for COVID-19 offers a timely and cost-efficient strategy to find treatments with established safety profiles. Notably, diphenhydramine, a sigma receptor ligand, is thought to counteract the virus by inhibiting the creation of ER-derived replication vesicles. Furthermore, lactoferrin, a well-characterized immunomodulatory protein, has shown antiviral efficacy against SARS-CoV-2 both in laboratory settings and in living organisms. In the present study, we aimed to explore the impact of sigma receptor ligands on SARS-CoV-2-induced mortality in ACE2-transgenic mice. We assessed the effects of an investigational antiviral drug combination comprising a sigma receptor ligand and an immunomodulatory protein. Mice treated with sigma-2 receptor ligands or diphenhydramine and lactoferrin exhibited improved survival rates and rapid rebound in mass following the SARS-CoV-2 challenge compared to mock-treated animals. Clinical translation of these findings may support the discovery of new treatment and research strategies for SARS-CoV-2.
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Affiliation(s)
- Reed L. Berkowitz
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (R.L.B.); (D.A.O.)
| | - Andrew P. Bluhm
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL 32611, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32601, USA
| | - Glenn W. Knox
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (R.L.B.); (D.A.O.)
| | - Christopher R. McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
- Translational Drug Development Core, Clinical and Translational Sciences Institute, University of Florida, Gainesville, FL 32610, USA
| | - David A. Ostrov
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (R.L.B.); (D.A.O.)
| | - Michael H. Norris
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32601, USA
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI 96822, USA
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Norris MH, Bluhm AP, Metrailer MC, Jiranantasak T, Kirpich A, Hadfield T, Ponciano JM, Blackburn JK. Beyond the spore, the exosporium sugar anthrose impacts vegetative Bacillus anthracis gene regulation in cis and trans. Sci Rep 2023; 13:5060. [PMID: 36977718 PMCID: PMC10050317 DOI: 10.1038/s41598-023-32162-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 03/23/2023] [Indexed: 03/30/2023] Open
Abstract
The Bacillus anthracis exosporium nap is the outermost portion of spore that interacts with the environment and host systems. Changes to this layer have the potential to impact wide-ranging physiological and immunological processes. The unique sugar, anthrose, normally coats the exosporium nap at its most distal points. We previously identified additional mechanisms rendering B. anthracis anthrose negative. In this work, several new ant - B. anthracis strains are identified and the impact of anthrose negativity on spore physiology is investigated. We demonstrate that live-attenuated Sterne vaccines as well as culture filtrate anthrax vaccines generate antibodies targeting non-protein components of the spore. The role of anthrose as a vegetative B. anthracis Sterne signaling molecule is implicated by luminescent expression strain assays, RNA-seq experiments, and toxin secretion analysis by western blot. Pure anthrose and the sporulation-inducing nucleoside analogue decoyinine had similar effects on toxin expression. Co-culture experiments demonstrated gene expression changes in B. anthracis depend on intracellular anthrose status (cis) in addition to anthrose status of extracellular interactions (trans). These findings provide a mechanism for how a unique spore-specific sugar residue affects physiology, expression and genetics of vegetative B. anthracis with impacts on the ecology, pathogenesis, and vaccinology of anthrax.
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Affiliation(s)
- Michael H Norris
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
| | - Andrew P Bluhm
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Morgan C Metrailer
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Treenate Jiranantasak
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Alexander Kirpich
- Department of Population Health Sciences, School of Public Health, Georgia State University, Atlanta, GA, USA
| | - Ted Hadfield
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | | | - Jason K Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
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Jiranantasak T, Benn JS, Metrailer MC, Sawyer SJ, Burns MQ, Bluhm AP, Blackburn JK, Norris MH. Characterization of Bacillus anthracis replication and persistence on environmental substrates associated with wildlife anthrax outbreaks. PLoS One 2022; 17:e0274645. [PMID: 36129912 PMCID: PMC9491531 DOI: 10.1371/journal.pone.0274645] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [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: 04/20/2022] [Accepted: 08/31/2022] [Indexed: 11/19/2022] Open
Abstract
Anthrax is a zoonosis caused by the environmentally maintained, spore-forming bacterium Bacillus anthracis, affecting humans, livestock, and wildlife nearly worldwide. Bacterial spores are ingested, inhaled, and may be mechanically transmitted by biting insects or injection as occurs during heroin-associated human cases. Herbivorous hoofstock are very susceptible to anthrax. When these hosts die of anthrax, a localized infectious zone (LIZ) forms in the area surrounding the carcass as it is scavenged and decomposes, where viable populations of vegetative B. anthracis and spores contaminate the environment. In many settings, necrophagous flies contaminate the outer carcass, surrounding soils, and vegetation with viable pathogen while scavenging. Field observations in Texas have confirmed this process and identified primary browse species (e.g., persimmon) are contaminated. However, there are limited data available on B. anthracis survival on environmental substrates immediately following host death at a LIZ. Toward this, we simulated fly contamination by inoculating live-attenuated, fully virulent laboratory-adapted, and fully virulent wild B. anthracis strains on untreated leaves and rocks for 2, 5, and 7 days. At each time point after inoculation, the number of vegetative cells and spores were determined. Sporulation rates were extracted from these different time points to enable comparison of sporulation speeds between B. anthracis strains with different natural histories. We found all B. anthracis strains used in this study could multiply for 2 or more days post inoculation and persist on leaves and rocks for at least seven days with variation by strain. We found differences in sporulation rates between laboratory-adapted strains and wild isolates, with the live-attenuated strain sporulating fastest, followed by the wild isolates, then laboratory-adapted virulent strains. Extrapolating our wild strain lab results to potential contamination, a single blow fly may contaminate leaves with up to 8.62 x 105 spores per day and a single carcass may host thousands of flies. Replication outside of the carcass and rapid sporulation confirms the LIZ extends beyond the carcass for several days after formation and supports the necrophagous fly transmission pathway for amplifying cases during an outbreak. We note caution must be taken when extrapolating replication and sporulation rates from live-attenuated and laboratory-adapted strains of B. anthracis.
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Affiliation(s)
- Treenate Jiranantasak
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jamie S. Benn
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Morgan C. Metrailer
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Samantha J. Sawyer
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Madison Q. Burns
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Andrew P. Bluhm
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jason K. Blackburn
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Michael H. Norris
- Department of Geography, Spatial Epidemiology & Ecology Research Laboratory, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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Grodzki M, Bluhm AP, Schaefer M, Tagmount A, Russo M, Sobh A, Rafiee R, Vulpe CD, Karst SM, Norris MH. Genome-scale CRISPR screens identify host factors that promote human coronavirus infection. Genome Med 2022; 14:10. [PMID: 35086559 PMCID: PMC8792531 DOI: 10.1186/s13073-022-01013-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [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: 10/29/2021] [Accepted: 01/10/2022] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The COVID-19 pandemic has resulted in 275 million infections and 5.4 million deaths as of December 2021. While effective vaccines are being administered globally, there is still a great need for antiviral therapies as antigenically novel SARS-CoV-2 variants continue to emerge across the globe. Viruses require host factors at every step in their life cycle, representing a rich pool of candidate targets for antiviral drug design. METHODS To identify host factors that promote SARS-CoV-2 infection with potential for broad-spectrum activity across the coronavirus family, we performed genome-scale CRISPR knockout screens in two cell lines (Vero E6 and HEK293T ectopically expressing ACE2) with SARS-CoV-2 and the common cold-causing human coronavirus OC43. Gene knockdown, CRISPR knockout, and small molecule testing in Vero, HEK293, and human small airway epithelial cells were used to verify our findings. RESULTS While we identified multiple genes and functional pathways that have been previously reported to promote human coronavirus replication, we also identified a substantial number of novel genes and pathways. The website https://sarscrisprscreens.epi.ufl.edu/ was created to allow visualization and comparison of SARS-CoV2 CRISPR screens in a uniformly analyzed way. Of note, host factors involved in cell cycle regulation were enriched in our screens as were several key components of the programmed mRNA decay pathway. The role of EDC4 and XRN1 in coronavirus replication in human small airway epithelial cells was verified. Finally, we identified novel candidate antiviral compounds targeting a number of factors revealed by our screens. CONCLUSIONS Overall, our studies substantiate and expand the growing body of literature focused on understanding key human coronavirus-host cell interactions and exploit that knowledge for rational antiviral drug development.
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Affiliation(s)
- Marco Grodzki
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Andrew P Bluhm
- Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Moritz Schaefer
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Abderrahmane Tagmount
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Max Russo
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
- Present address: Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Amin Sobh
- Univeristy of Florida Heath Cancer Center, University of Florida, Gainesville, FL, USA
| | - Roya Rafiee
- Department of Pharmacotherapy and Translational Research, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Chris D Vulpe
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA
| | - Stephanie M Karst
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL, USA.
| | - Michael H Norris
- Department of Geography, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, USA.
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
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Heacock-Kang Y, McMillan IA, Norris MH, Sun Z, Zarzycki-Siek J, Bluhm AP, Cabanas D, Norton RE, Ketheesan N, Miller JF, Schweizer HP, Hoang TT. The Burkholderia pseudomallei intracellular 'TRANSITome'. Nat Commun 2021; 12:1907. [PMID: 33772012 PMCID: PMC7998038 DOI: 10.1038/s41467-021-22169-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 02/26/2021] [Indexed: 01/01/2023] Open
Abstract
Prokaryotic cell transcriptomics has been limited to mixed or sub-population dynamics and individual cells within heterogeneous populations, which has hampered further understanding of spatiotemporal and stage-specific processes of prokaryotic cells within complex environments. Here we develop a 'TRANSITomic' approach to profile transcriptomes of single Burkholderia pseudomallei cells as they transit through host cell infection at defined stages, yielding pathophysiological insights. We find that B. pseudomallei transits through host cells during infection in three observable stages: vacuole entry; cytoplasmic escape and replication; and membrane protrusion, promoting cell-to-cell spread. The B. pseudomallei 'TRANSITome' reveals dynamic gene-expression flux during transit in host cells and identifies genes that are required for pathogenesis. We find several hypothetical proteins and assign them to virulence mechanisms, including attachment, cytoskeletal modulation, and autophagy evasion. The B. pseudomallei 'TRANSITome' provides prokaryotic single-cell transcriptomics information enabling high-resolution understanding of host-pathogen interactions.
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Affiliation(s)
- Yun Heacock-Kang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Ian A McMillan
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Michael H Norris
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Zhenxin Sun
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Darlene Cabanas
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Robert E Norton
- Townsville Hospital, Townsville, QLD, Australia
- Faculty of Medicine, University of Queensland, Brisbane, Australia
| | - Natkunam Ketheesan
- Science and Technology, University of New England, New South Wales, Australia
| | - Jeff F Miller
- Department of Microbiology, Immunology, and Molecular Genetics, and the California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Herbert P Schweizer
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Tung T Hoang
- School of Life Sciences, University of Hawai'i at Mānoa, Honolulu, HI, USA.
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Norris MH, Kirpich A, Bluhm AP, Zincke D, Hadfield T, Ponciano JM, Blackburn JK. Correction: Convergent evolution of diverse Bacillus anthracis outbreak strains toward altered surface oligosaccharides that modulate anthrax pathogenesis. PLoS Biol 2021; 19:e3001112. [PMID: 33556066 PMCID: PMC7869985 DOI: 10.1371/journal.pbio.3001112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
[This corrects the article DOI: 10.1371/journal.pbio.3001052.].
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Reznikov LR, Norris MH, Vashisht R, Bluhm AP, Li D, Liao YSJ, Brown A, Butte AJ, Ostrov DA. Identification of antiviral antihistamines for COVID-19 repurposing. Biochem Biophys Res Commun 2021; 538:173-179. [PMID: 33309272 PMCID: PMC7713548 DOI: 10.1016/j.bbrc.2020.11.095] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023]
Abstract
There is an urgent need to identify therapies that prevent SARS-CoV-2 infection and improve the outcome of COVID-19 patients. Although repurposed drugs with favorable safety profiles could have significant benefit, widely available prevention or treatment options for COVID-19 have yet to be identified. Efforts to identify approved drugs with in vitro activity against SARS-CoV-2 resulted in identification of antiviral sigma-1 receptor ligands, including antihistamines in the histamine-1 receptor binding class. We identified antihistamine candidates for repurposing by mining electronic health records of usage in population of more than 219,000 subjects tested for SARS-CoV-2. Usage of diphenhydramine, hydroxyzine and azelastine was associated with reduced incidence of SARS-CoV-2 positivity in subjects greater than age 61. We found diphenhydramine, hydroxyzine and azelastine to exhibit direct antiviral activity against SARS-CoV-2 in vitro. Although mechanisms by which specific antihistamines exert antiviral effects is not clear, hydroxyzine, and possibly azelastine, bind Angiotensin Converting Enzyme-2 (ACE2) and the sigma-1 receptor as off-targets. Clinical studies are needed to measure the effectiveness of diphenhydramine, hydroxyzine and azelastine for disease prevention, for early intervention, or as adjuvant therapy for severe COVID-19.
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Affiliation(s)
- Leah R Reznikov
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA
| | - Michael H Norris
- Department of Geography and the Emerging Pathogens Institute, Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL, USA
| | - Rohit Vashisht
- Bakar Computational Health Sciences Institute, University of California San Francisco, San Francisco, CA, USA
| | - Andrew P Bluhm
- Department of Geography and the Emerging Pathogens Institute, Spatial Epidemiology and Ecology Research Laboratory, University of Florida, Gainesville, FL, USA
| | - Danmeng Li
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Yan-Shin J Liao
- Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA
| | - Ashley Brown
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL, USA
| | - Atul J Butte
- Bakar Computational Health Sciences Institute, University of California San Francisco, San Francisco, CA, USA
| | - David A Ostrov
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL, USA.
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Norris MH, Kirpich A, Bluhm AP, Zincke D, Hadfield T, Ponciano JM, Blackburn JK. Convergent evolution of diverse Bacillus anthracis outbreak strains toward altered surface oligosaccharides that modulate anthrax pathogenesis. PLoS Biol 2020; 18:e3001052. [PMID: 33370274 PMCID: PMC7793302 DOI: 10.1371/journal.pbio.3001052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 05/29/2020] [Revised: 01/08/2021] [Accepted: 12/14/2020] [Indexed: 11/19/2022] Open
Abstract
Bacillus anthracis, a spore-forming gram-positive bacterium, causes anthrax. The external surface of the exosporium is coated with glycosylated proteins. The sugar additions are capped with the unique monosaccharide anthrose. The West African Group (WAG) B. anthracis have mutations rendering them anthrose deficient. Through genome sequencing, we identified 2 different large chromosomal deletions within the anthrose biosynthetic operon of B. anthracis strains from Chile and Poland. In silico analysis identified an anthrose-deficient strain in the anthrax outbreak among European heroin users. Anthrose-deficient strains are no longer restricted to West Africa so the role of anthrose in physiology and pathogenesis was investigated in B. anthracis Sterne. Loss of anthrose delayed spore germination and enhanced sporulation. Spores without anthrose were phagocytized at higher rates than spores with anthrose, indicating that anthrose may serve an antiphagocytic function on the spore surface. The anthrose mutant had half the LD50 and decreased time to death (TTD) of wild type and complement B. anthracis Sterne in the A/J mouse model. Following infection, anthrose mutant bacteria were more abundant in the spleen, indicating enhanced dissemination of Sterne anthrose mutant. At low sample sizes in the A/J mouse model, the mortality of ΔantC-infected mice challenged by intranasal or subcutaneous routes was 20% greater than wild type. Competitive index (CI) studies indicated that spores without anthrose disseminated to organs more extensively than a complemented mutant. Death process modeling using mouse mortality dynamics suggested that larger sample sizes would lead to significantly higher deaths in anthrose-negative infected animals. The model was tested by infecting Galleria mellonella with spores and confirmed the anthrose mutant was significantly more lethal. Vaccination studies in the A/J mouse model showed that the human vaccine protected against high-dose challenges of the nonencapsulated Sterne-based anthrose mutant. This work begins to identify the physiologic and pathogenic consequences of convergent anthrose mutations in B. anthracis.
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Affiliation(s)
- Michael H. Norris
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Alexander Kirpich
- Department of Population Health Services, Georgia State University, Atlanta, Georgia, United States of America
| | - Andrew P. Bluhm
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Diansy Zincke
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Ted Hadfield
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Jose Miguel Ponciano
- Department of Biology, University of Florida, Gainesville, Florida, United States of America
| | - Jason K. Blackburn
- Spatial Epidemiology & Ecology Research Laboratory, Department of Geography, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
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Norris MH, Tran HTT, Walker MA, Bluhm AP, Zincke D, Trung TT, Thi NV, Thi NP, Schweizer HP, Unger F, Blackburn JK, Hang NTT. Distribution of Serological Response to Burkholderia pseudomallei in Swine from Three Provinces of Vietnam. Int J Environ Res Public Health 2020; 17:ijerph17145203. [PMID: 32708490 PMCID: PMC7399857 DOI: 10.3390/ijerph17145203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/09/2020] [Accepted: 07/16/2020] [Indexed: 01/18/2023]
Abstract
(1) Background: Burkholderia pseudomallei is an environmentally mediated saprophytic pathogen that can cause severe disease in humans. It is well known that B. pseudomallei survives in tropical moist soil environments worldwide, but melioidosis is gaining recognition as a public and veterinary health issue in Vietnam. The contribution of animals to human disease is unknown, necessitating further investigation. (2) Methods: Swine sera were collected from two populations, one grazing and one commercially farmed, from three provinces in Vietnam. ELISAs utilizing B. pseudomallei capsular polysaccharide (CPS), outer polysaccharide (OPS), and Hcp1 protein were used to screen serum samples. Positive samples were mapped to the commune level. Seroprevalence calculations and pig population estimates were used to approximate number of swine exposures per commune. (3) Results: Grazing pigs from Hoa Binh had significantly higher seropositivity levels (11.4%, 95% CI: 9.7–13.1) compared to farmed pigs from Ha Tinh and Nghe An (4%, 95% CI: 3.3–4.7). Average swine seropositivity rates were ~6.3% (95% CI: 5–7.9), higher than previously identified in Vietnam (~0.88%). (4) Conclusions: Initial serological sampling identified a significant number of seropositive and potential melioidosis infections occurring in swine in Vietnam. This work is a critical step in understanding the role swine may play in the epidemiology of human melioidosis in Vietnam.
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Affiliation(s)
- Michael H. Norris
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
- Correspondence:
| | - Hang Thi Thu Tran
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Morgan A. Walker
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Andrew P. Bluhm
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Diansy Zincke
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Trinh Thanh Trung
- VNU-Institute of Microbiology and Biotechnology, Vietnam National University, Hanoi 10000, Vietnam;
| | - Nga Vu Thi
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Ngoc Pham Thi
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
| | - Herbert P. Schweizer
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA
| | - Fred Unger
- International Livestock Research Institute, Hanoi 10000, Vietnam;
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Lab, Department of Geography, University of Florida, Gainesville, FL 32611, USA; (M.A.W.); (A.P.B.); (D.Z.); (J.K.B.)
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32611, USA;
| | - Nguyen Thi Thu Hang
- National Institute of Veterinary Research, Hanoi 10000, Vietnam; (H.T.T.T.); (N.V.T.); (N.P.T.); (N.T.T.H.)
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10
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Heacock-Kang Y, McMillan IA, Zarzycki-Siek J, Sun Z, Bluhm AP, Cabanas D, Hoang TT. The heritable natural competency trait of Burkholderia pseudomallei in other Burkholderia species through comE and crp. Sci Rep 2018; 8:12422. [PMID: 30127446 PMCID: PMC6102250 DOI: 10.1038/s41598-018-30853-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [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: 03/12/2018] [Accepted: 08/02/2018] [Indexed: 11/17/2022] Open
Abstract
Natural competency requires uptake of exogenous DNA from the environment and the integration of that DNA into recipient bacteria can be used for DNA-repair or genetic diversification. The Burkholderia genus is unique in that only some of the species and strains are naturally competent. We identified and characterized two genes, comE and crp, from naturally competent B. pseudomallei 1026b that play a role in DNA uptake and catabolism. Single-copies of rhamnose-inducible comE and crp genes were integrated into a Tn7 attachment-site in non-naturally competent Burkholderia including pathogens B. pseudomallei K96243, B. cenocepacia K56-2, and B. mallei ATCC23344. Strains expressing comE or crp were assayed for their ability to uptake and catabolize DNA. ComE and Crp allowed non-naturally competent Burkholderia species to catabolize DNA, uptake exogenous gfp DNA and express GFP. Furthermore, we used synthetic comE and crp to expand the utility of the λ-red recombineering system for genetic manipulation of non-competent Burkholderia species. A newly constructed vector, pKaKa4, was used to mutate the aspartate semialdehyde dehydrogenase (asd) gene in four B. mallei strains, leading to the complete attenuation of these tier-1 select-agents. These strains have been excluded from select-agent regulations and will be of great interest to the field.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
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11
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Heacock-Kang Y, Zarzycki-Siek J, Sun Z, Poonsuk K, Bluhm AP, Cabanas D, Fogen D, McMillan IA, Chuanchuen R, Hoang TT. Novel dual regulators of Pseudomonas aeruginosa essential for productive biofilms and virulence. Mol Microbiol 2018; 109:401-414. [PMID: 29995308 PMCID: PMC6158065 DOI: 10.1111/mmi.14063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [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] [Accepted: 06/25/2018] [Indexed: 01/14/2023]
Abstract
Gene regulation network in Pseudomonas aeruginosa is complex. With a relatively large genome (6.2 Mb), there is a significant portion of genes that are proven or predicted to be transcriptional regulators. Many of these regulators have been shown to play important roles in biofilm formation and maintenance. In this study, we present a novel transcriptional regulator, PA1226, which modulates biofilm formation and virulence in P. aeruginosa. Mutation in the gene encoding this regulator abolished the ability of P. aeruginosa to produce biofilms in vitro, without any effect on the planktonic growth. This regulator is also essential for the in vivo fitness and pathogenesis in both Drosophila melanogaster and BALB/c mouse lung infection models. Transcriptome analysis revealed that PA1226 regulates many essential virulence genes/pathways, including those involved in alginate, pili, and LPS biosynthesis. Genes/operons directly regulated by PA1226 and potential binding sequences were identified via ChIP-seq. Attempts to confirm the binding sequences by electrophoretic mobility shift assay led to the discovery of a co-regulator, PA1413, via co-immunoprecipitation assay. PA1226 and PA1413 were shown to bind collaboratively to the promoter regions of their regulons. A model is proposed, summarizing our finding on this novel dual-regulation system.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Kanchana Poonsuk
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
| | - Rungtip Chuanchuen
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, 96822, USA
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12
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Norris MH, Heacock-Kang Y, Zarzycki-Siek J, Bluhm AP, McMillan IA, Schweizer HP, Hoang TT. Burkholderia pseudomallei natural competency and DNA catabolism: Identification and characterization of relevant genes from a constructed fosmid library. PLoS One 2017; 12:e0189018. [PMID: 29253888 PMCID: PMC5734746 DOI: 10.1371/journal.pone.0189018] [Citation(s) in RCA: 4] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 11/18/2017] [Indexed: 11/19/2022] Open
Abstract
Burkholderia spp. are genetically and physiologically diverse. Some strains are naturally transformable and capable of DNA catabolism. Burkholderia pseudomallei (Bp) strains 1026b and K96243 and B. thailandensis strain E264 are able to utilize DNA as a sole carbon source for growth, while only strains 1026b and E264 are naturally transformable. In this study, we constructed low-copy broad-host-range fosmid library, containing Bp strain 1026b chromosomal DNA fragments, and employed a novel positive selection approach to identify genes responsible for DNA uptake and DNA catabolism. The library was transferred to non-competent Bp K96243 and B. cenocepacia (Bc) K56-2, harboring chromosomally-inserted FRT-flanked sacB and pheS counter-selection markers. The library was incubated with DNA encoding Flp recombinase, followed by counter-selection on sucrose and chlorinated phenylalanine, to select for clones that took up flp-DNA, transiently expressed Flp, and excised the sacB-pheS cassette. Putative clones that survived the counter-selection were subsequently incubated with gfp-DNA and bacteria were visualized via fluorescent microscopy to confirm natural competency. Fosmid sequencing identified several 1026b genes implicated in DNA uptake, which were validated using chromosomal mutants. One of the naturally competent clones selected in Bc K56-2 enabled Bc, Bp and B. mallei to utilize DNA as a sole carbon source, and all fosmids were used to successfully create mutations in non-naturally-competent B. mallei and Bp strains.
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Affiliation(s)
- Michael H. Norris
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Infectious Diseases and Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Andrew P. Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Ian A. McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, United States of America
| | - Herbert P. Schweizer
- Department of Molecular Genetics and Microbiology, College of Medicine and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Tung T. Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, United States of America
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, United States of America
- * E-mail:
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13
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Heacock-Kang Y, Sun Z, Zarzycki-Siek J, McMillan IA, Norris MH, Bluhm AP, Cabanas D, Fogen D, Vo H, Donachie SP, Borlee BR, Sibley CD, Lewenza S, Schurr MJ, Schweizer HP, Hoang TT. Spatial transcriptomes within the Pseudomonas aeruginosa biofilm architecture. Mol Microbiol 2017; 106:976-985. [PMID: 29030956 PMCID: PMC5720903 DOI: 10.1111/mmi.13863] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [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] [Accepted: 10/12/2017] [Indexed: 01/24/2023]
Abstract
Bacterial cooperative associations and dynamics in biofilm microenvironments are of special interest in recent years. Knowledge of localized gene‐expression and corresponding bacterial behaviors within the biofilm architecture at a global scale has been limited, due to a lack of robust technology to study limited number of cells in stratified layers of biofilms. With our recent pioneering developments in single bacterial cell transcriptomic analysis technology, we generated herein an unprecedented spatial transcriptome map of the mature in vitro Pseudomonas aeruginosa biofilm model, revealing contemporaneous yet altered bacterial behaviors at different layers within the biofilm architecture (i.e., surface, middle and interior of the biofilm). Many genes encoding unknown functions were highly expressed at the biofilm‐solid interphase, exposing a critical gap in the knowledge of their activities that may be unique to this interior niche. Several genes of unknown functions are critical for biofilm formation. The in vivo importance of these unknown proteins was validated in invertebrate (fruit fly) and vertebrate (mouse) models. We envisage the future value of this report to the community, in aiding the further pathophysiological understanding of P. aeruginosa biofilms. Our approach will open doors to the study of bacterial functional genomics of different species in numerous settings.
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Affiliation(s)
- Yun Heacock-Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Ian A McMillan
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Michael H Norris
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Andrew P Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Darlene Cabanas
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Dawson Fogen
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Hung Vo
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Stuart P Donachie
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Bradley R Borlee
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Christopher D Sibley
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Shawn Lewenza
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
| | - Michael J Schurr
- Department of Immunology and Microbiology, University of Colorado, Aurora, CO, USA
| | - Herbert P Schweizer
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, USA
| | - Tung T Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, HI, USA.,Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
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14
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Enright HA, Bratt JM, Bluhm AP, Kenyon NJ, Louie AY. Tracking retention and transport of ultrafine polystyrene in an asthmatic mouse model using positron emission tomography. Exp Lung Res 2013; 39:304-13. [PMID: 23919375 DOI: 10.3109/01902148.2013.819048] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Upon exposure to particulates, asthmatic individuals are more susceptible to deleterious health effects and increased morbidity and mortality when compared to healthy individuals. These effects are not limited to the respiratory system; increases in acute cardiovascular events have been observed. The development of extrapulmonary illnesses has led to interest in determining whether particles move out of the lungs and whether transport of particles differs for asthmatic individuals. Differences in particle deposition and retention in asthmatic versus normal subjects have been explored in the literature using the gamma camera, a two-dimensional imaging technique. Herein we report the deposition and fate of (64)Cu-labeled 100 nm polystyrene particles in a mouse model of asthma using positron emission tomography (PET). All animals were handled humanely under an approved protocol (UC Davis Institutional Animal Care and Use Committee). Particles were administered by intratracheal instillation and animals were imaged over 48 hours using PET. Biodistribution was determined from images using Regions of Interest (ROI) analysis. After 48 hours, for the asthmatic animals, we observed that ~28% of the initial dose is cleared from the lungs; particle accumulation in small amounts is evident in the GI (gastrointestinal) tract, liver, and bladder. This decrease in lung retention is significantly different when compared to the normal mouse (~11%DD), which showed minimal particle transport out of the lung (P < 0.001). This study indicates that ultrafine particles (UFP) undergo enhanced transport out of the lungs in an asthma model. This observed transport may facilitate the adverse peripheral effects associated with particulate exposure.
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Affiliation(s)
- Heather A Enright
- Department of Chemistry, University of California-Davis, Davis, California 95616, USA
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15
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Zarzycki-Siek J, Norris MH, Kang Y, Sun Z, Bluhm AP, McMillan IA, Hoang TT. Elucidating the Pseudomonas aeruginosa fatty acid degradation pathway: identification of additional fatty acyl-CoA synthetase homologues. PLoS One 2013; 8:e64554. [PMID: 23737986 PMCID: PMC3667196 DOI: 10.1371/journal.pone.0064554] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [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: 01/16/2013] [Accepted: 04/16/2013] [Indexed: 01/22/2023] Open
Abstract
The fatty acid (FA) degradation pathway of Pseudomonas aeruginosa, an opportunistic pathogen, was recently shown to be involved in nutrient acquisition during BALB/c mouse lung infection model. The source of FA in the lung is believed to be phosphatidylcholine, the major component of lung surfactant. Previous research indicated that P. aeruginosa has more than two fatty acyl-CoA synthetase genes (fadD; PA3299 and PA3300), which are responsible for activation of FAs using ATP and coenzyme A. Through a bioinformatics approach, 11 candidate genes were identified by their homology to the Escherichia coli FadD in the present study. Four new homologues of fadD (PA1617, PA2893, PA3860, and PA3924) were functionally confirmed by their ability to complement the E. coli fadD mutant on FA-containing media. Growth phenotypes of 17 combinatorial fadD mutants on different FAs, as sole carbon sources, indicated that the four new fadD homologues are involved in FA degradation, bringing the total number of P. aeruginosa fadD genes to six. Of the four new homologues, fadD4 (PA1617) contributed the most to the degradation of different chain length FAs. Growth patterns of various fadD mutants on plant-based perfumery substances, citronellic and geranic acids, as sole carbon and energy sources indicated that fadD4 is also involved in the degradation of these plant-derived compounds. A decrease in fitness of the sextuple fadD mutant, relative to the ΔfadD1D2 mutant, was only observed during BALB/c mouse lung infection at 24 h.
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Affiliation(s)
- Jan Zarzycki-Siek
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Michael H. Norris
- Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Yun Kang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Zhenxin Sun
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Andrew P. Bluhm
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Ian A. McMillan
- Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Tung T. Hoang
- Department of Microbiology, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- Department of Molecular Bioscience and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
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