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Barksdale SM, Hrifko EJ, van Hoek ML. Cathelicidin antimicrobial peptide from Alligator mississippiensis has antibacterial activity against multi-drug resistant Acinetobacter baumanii and Klebsiella pneumoniae. Dev Comp Immunol 2017; 70:135-144. [PMID: 28089718 DOI: 10.1016/j.dci.2017.01.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
Alligator mississippiensis (American alligator), a member of order Crocodilia, lives in bacteria-laden environments but is not often known to succumb to bacterial infections. Their serum has been shown to have antibacterial activity beyond that of human serum, and it is believed that this activity is partially due to cationic antimicrobial peptides (CAMPs). CAMPs are produced by many organisms as part of the innate immune system. CAMPs are attractive possible therapies against multi-drug resistant bacteria, such as those found in biofilm-infected war wounds, because they seldom cause genetic resistance in bacteria and are effective against antibiotic resistant bacteria. In this work, we identified, synthesized, and characterized a cathelicidin and two shorter fragments from the American alligator. We discovered the cathelicidin using Basic Local Alignment Search Tool (BLAST) alignment and by comparing A. mississippiensis expressed sequence tags (ESTs) with propeptide cathelicidins of other reptiles. We analyzed the structure using bioinformatics tools and circular dichroism and predicted that the full-length cathelicidin peptide has a mixed structure, with an N-terminal α-helix and a center Pro hinge. In minimal inhibitory concentration (MIC) assays, it was determined that the cathelicidin and the two shorter fragments have strong activity against multiple Gram-negative bacteria, including clinical isolates of multi-drug resistant (MDR) Acinetobacter baumannii and carbapenem-resistant Klebsiella pneumoniae. Using the ethidium bromide uptake assay, it was found that these peptides permeabilize the bacterial membrane and are less sensitive to salt inhibition than many other known CAMPs. The alligator cathelicidin peptides were not hemolytic against sheep red blood cells at 300 μg/ml and were not significantly cytotoxic against A549 human lung epithelial cells after 24 h exposure in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. These alligator cathelicidin peptides have activity similar to other CAMPs from reptiles such as NA-CATH. It is possible that the alligator cathelicidins play an important role in the innate immune response of A. mississippiensis, similar to LL-37 in humans. In addition, due to their activities against MDR bacteria and lack of cytotoxicity, the AM-CATH peptides could be an attractive platform for further development as a potential therapeutic.
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Affiliation(s)
| | - Evelyn J Hrifko
- College of Science, George Mason University, Manassas, VA, USA
| | - Monique L van Hoek
- School of Systems Biology, George Mason University, Manassas, VA, USA; College of Science, George Mason University, Manassas, VA, USA; National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, VA, USA.
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Bishop BM, Juba ML, Russo PS, Devine M, Barksdale SM, Scott S, Settlage R, Michalak P, Gupta K, Vliet K, Schnur JM, van Hoek ML. Discovery of Novel Antimicrobial Peptides from Varanus komodoensis (Komodo Dragon) by Large-Scale Analyses and De-Novo-Assisted Sequencing Using Electron-Transfer Dissociation Mass Spectrometry. J Proteome Res 2017; 16:1470-1482. [PMID: 28164707 DOI: 10.1021/acs.jproteome.6b00857] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [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: 11/29/2022]
Abstract
Komodo dragons are the largest living lizards and are the apex predators in their environs. They endure numerous strains of pathogenic bacteria in their saliva and recover from wounds inflicted by other dragons, reflecting the inherent robustness of their innate immune defense. We have employed a custom bioprospecting approach combining partial de novo peptide sequencing with transcriptome assembly to identify cationic antimicrobial peptides from Komodo dragon plasma. Through these analyses, we identified 48 novel potential cationic antimicrobial peptides. All but one of the identified peptides were derived from histone proteins. The antimicrobial effectiveness of eight of these peptides was evaluated against Pseudomonas aeruginosa (ATCC 9027) and Staphylococcus aureus (ATCC 25923), with seven peptides exhibiting antimicrobial activity against both microbes and one only showing significant potency against P. aeruginosa. This study demonstrates the power and promise of our bioprospecting approach to cationic antimicrobial peptide discovery, and it reveals the presence of a plethora of novel histone-derived antimicrobial peptides in the plasma of the Komodo dragon. These findings may have broader implications regarding the role that intact histones and histone-derived peptides play in defending the host from infection. Data are available via ProteomeXChange with identifier PXD005043.
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Affiliation(s)
- Barney M Bishop
- Department of Chemistry and Biochemistry, George Mason University , 10920 George Mason Circle, 4C7, Manassas, Virginia, 20110, United States
| | - Melanie L Juba
- Department of Chemistry and Biochemistry, George Mason University , 10920 George Mason Circle, 4C7, Manassas, Virginia, 20110, United States
| | - Paul S Russo
- Center for Applied Proteomics and Molecular Medicine, George Mason University , 10920 George Mason Circle, 1A9, Manassas, Virginia 20110, United States
| | - Megan Devine
- Department of Chemistry and Biochemistry, George Mason University , 10920 George Mason Circle, 4C7, Manassas, Virginia, 20110, United States
| | - Stephanie M Barksdale
- School of Systems Biology, George Mason University , 10920 George Mason Circle, 1H8, Manassas, Virginia 20110, United States
| | - Shaylyn Scott
- Department of Chemistry and Biochemistry, George Mason University , 10920 George Mason Circle, 4C7, Manassas, Virginia, 20110, United States
| | - Robert Settlage
- Advanced Research Computing, Virginia Polytechnic Institute and State University , 620 Drillfield Drive, Blacksburg, Virginia 24061, United States
| | - Pawel Michalak
- Biocomplexity Institute, Virginia Polytechnic Institute and State University , 1015 Life Science Circle, Blacksburg, Virginia 24061, United States
| | - Kajal Gupta
- College of Science, George Mason University , 4400 University Drive, 5C3, Fairfax, Virginia 22030, United States
| | - Kent Vliet
- Department of Biology, University of Florida , 876 Newell Drive, PO Box 118525, Gainesville, Florida 32511, United States
| | - Joel M Schnur
- College of Science, George Mason University , 4400 University Drive, 5C3, Fairfax, Virginia 22030, United States
| | - Monique L van Hoek
- School of Systems Biology, George Mason University , 10920 George Mason Circle, 1H8, Manassas, Virginia 20110, United States
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Barksdale SM, Hrifko EJ, Chung EMC, van Hoek ML. Peptides from American alligator plasma are antimicrobial against multi-drug resistant bacterial pathogens including Acinetobacter baumannii. BMC Microbiol 2016; 16:189. [PMID: 27542832 PMCID: PMC4992317 DOI: 10.1186/s12866-016-0799-z] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/04/2016] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Our group has developed a new process for isolating and identifying novel cationic antimicrobial peptides from small amounts of biological samples. Previously, we identified several active antimicrobial peptides from 100 μl of plasma from Alligator mississippiensis. These peptides were found to have in vitro antimicrobial activity against Pseudomonas aeruginosa and Staphylococcus aureus. In this work, we further characterize three of the novel peptides discovered using this process: Apo5, Apo6, and A1P. RESULTS We examined the activity of these peptides against multi-drug resistant strains and clinical isolates of common human pathogens. We investigated their structural characteristics using circular dichroism and tested for membrane disruption and DNA binding. These peptides were found to have strong in vitro activity against multi-drug resistant and clinically isolated strains of S. aureus, Escherichia coli, P. aeruginosa, and Acinetobacter baumannii. Apo5 and Apo6, peptides derived from alligator apolipoprotein C-1, depolarized the bacterial membrane. A1P, a peptide from the serpin proteinase inhibitor, did not permeabilize membranes. Performing circular dichroism analysis, Apo5 and Apo6 were found to be predominantly helical in SDS and TFE buffer, while A1P has significantly different structures in phosphate buffer, SDS, and TFE. None of these peptides were found to be hemolytic to sheep red blood cells or significantly cytotoxic up to 100 μg/ml after 24 h exposure. CONCLUSIONS Overall, we suggest that Apo5 and Apo6 have a different mode of action than A1P, and that all three peptides make promising candidates for the treatment of drug-resistant bacteria, such as A. baumannii.
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Affiliation(s)
| | - Evelyn J Hrifko
- College of Science, George Mason University, Manassas, VA, USA
| | - Ezra Myung-Chul Chung
- National Center of Biodefense and Infectious Diseases, George Mason University, 10920 George Mason Cir, 10920 George Mason Circle, MSN 1H8, Manassas, VA, 20110, USA.,Present Address: STCube Pharmaceuticals, Inc., 401 Professional Dr. Suite 108, Gaithersburg, MD, 20879-3429, USA
| | - Monique L van Hoek
- School of Systems Biology, George Mason University, Manassas, VA, USA. .,National Center of Biodefense and Infectious Diseases, George Mason University, 10920 George Mason Cir, 10920 George Mason Circle, MSN 1H8, Manassas, VA, 20110, USA.
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Abstract
Burkholderia thailandensis is a Gram-negative soil bacterium used as a model organism for B. pseudomallei, the causative agent of melioidosis and an organism classified category B priority pathogen and a Tier 1 select agent for its potential use as a biological weapon. Burkholderia species are reportedly “highly resistant” to antimicrobial agents, including cyclic peptide antibiotics, due to multiple resistance systems, a hypothesis we decided to test using antimicrobial (host defense) peptides. In this study, a number of cationic antimicrobial peptides (CAMPs) were tested in vitro against B. thailandensis for both antimicrobial activity and inhibition of biofilm formation. Here, we report that the Chinese cobra (Naja atra) cathelicidin NA-CATH was significantly antimicrobial against B. thailandensis. Additional cathelicidins, including the human cathelicidin LL-37, a sheep cathelicidin SMAP-29, and some smaller ATRA peptide derivatives of NA-CATH were also effective. The D-enantiomer of one small peptide (ATRA-1A) was found to be antimicrobial as well, with EC50 in the range of the L-enantiomer. Our results also demonstrate that human alpha-defensins (HNP-1 & -2) and a short beta-defensin-derived peptide (Peptide 4 of hBD-3) were not bactericidal against B. thailandensis. We also found that the cathelicidin peptides, including LL-37, NA-CATH, and SMAP-29, possessed significant ability to prevent biofilm formation of B. thailandensis. Additionally, we show that LL-37 and its D-enantiomer D-LL-37 can disperse pre-formed biofilms. These results demonstrate that although B. thailandensis is highly resistant to many antibiotics, cyclic peptide antibiotics such as polymyxin B, and defensing peptides, some antimicrobial peptides including the elapid snake cathelicidin NA-CATH exert significant antimicrobial and antibiofilm activity towards B. thailandensis. Burkholderia species such as B. pseudomallei, which causes melioidosis, and the model organism B. thailandensis are extremely resistant to antibiotics, including cyclic peptide antibiotics such as polymyxin B. Treatment for Burkholderia infections is impeded by this resistance, and new approaches are needed. We hypothesized that the cathelicidin NA-CATH from the Chinese cobra, Naja atra, and smaller derivative peptides (ATRA peptides) may have antimicrobial activity against Burkholderia. We therefore tested the bactericidal effects of the cathelicidin and its derivative peptides. We also wanted to determine whether the antimicrobial peptides exert anti-biofilm activity, although the role of biofilm as a critical virulence factor of Burkholderia has not yet been established. We found that the peptide ATRA-1A, as well as the stereo-isomer D-ATRA-1A, were able to kill B. thailandensis, and the full-length snake cathelicidin NA-CATH was able to both kill B. thailandensis and inhibit its biofilm formation, unlike the human-alpha defensin peptides HNP-1 and HNP-2, and the small peptide derived from hBD3. These results show that the NA-CATH antimicrobial peptide possess bactericidal and anti-biofilm activity against B. thailandensis, and suggest that these compounds should be tested for their effect against the more virulent strains of Burkholderia.
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Affiliation(s)
- Ryan J. Blower
- George Mason University, School of Systems Biology, Manassas, Virginia, United States of America
| | - Stephanie M. Barksdale
- George Mason University, School of Systems Biology, Manassas, Virginia, United States of America
| | - Monique L. van Hoek
- George Mason University, School of Systems Biology, Manassas, Virginia, United States of America
- George Mason University, National Center for Biodefense and Infectious Diseases, Manassas, Virginia, United States of America
- * E-mail:
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Juba ML, Porter DK, Williams EH, Rodriguez CA, Barksdale SM, Bishop BM. Helical cationic antimicrobial peptide length and its impact on membrane disruption. Biochimica et Biophysica Acta (BBA) - Biomembranes 2015; 1848:1081-91. [DOI: 10.1016/j.bbamem.2015.01.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 12/31/2014] [Accepted: 01/11/2015] [Indexed: 11/25/2022]
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Ulrey RK, Barksdale SM, Zhou W, van Hoek ML. Cranberry proanthocyanidins have anti-biofilm properties against Pseudomonas aeruginosa. BMC Complement Altern Med 2014; 14:499. [PMID: 25511463 PMCID: PMC4320558 DOI: 10.1186/1472-6882-14-499] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [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: 04/27/2014] [Accepted: 12/11/2014] [Indexed: 02/08/2023]
Abstract
BACKGROUND Bacteria within a biofilm are phenotypically more resistant to antibiotics, desiccation, and the host immune system, making it an important virulence factor for many microbes. Cranberry juice has long been used to prevent infections of the urinary tract, which are often related to biofilm formation. Recent studies have found that the A-type proanthocyanidins from cranberries have anti-biofilm properties against Escherichia coli. METHODS Using crystal violet biofilm staining, resazurin metabolism assays, and confocal imaging, we examined the ability of A-type proanthocyanidins (PACs) to disrupt the biofilm formation of Pseudomonas aeruginosa. We used mass spectrometry to analyze the proteomic effects of PAC treatment. We also performed synergy assays and in vitro and in vivo infections to determine whether PACs, alone and in combination with gentamicin, could contribute to the killing of P. aeruginosa and the survival of cell lines and G. mellonella. RESULTS Cranberry PACs reduced P. aeruginosa swarming motility. Cranberry PACs significantly disrupted the biofilm formation of P. aeruginosa. Proteomics analysis revealed significantly different proteins expressed following PAC treatment. In addition, we found that PACs potentiated the antibiotic activity of gentamicin in an in vivo model of infection using G. mellonella. CONCLUSIONS Results suggest that A-type proanthocyanidins may be a useful therapeutic against the biofilm-mediated infections caused by P. aeruginosa and should be further tested.
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Affiliation(s)
- Robert K Ulrey
- />Department of Biology, George Mason University, Manassas, Virginia USA
| | | | - Weidong Zhou
- />Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, Virginia USA
| | - Monique L van Hoek
- />School of Systems Biology, George Mason University, Manassas, Virginia USA
- />National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia USA
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