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Xiao T, Liu K, Gao Q, Chen M, Kim YS, Jin S, Ding Y, Huigens RW. Design, Synthesis, and Evaluation of Carbonate-Linked Halogenated Phenazine-Quinone Prodrugs with Improved Water-Solubility and Potent Antibacterial Profiles. ACS Infect Dis 2023; 9:899-915. [PMID: 36867688 PMCID: PMC10551733 DOI: 10.1021/acsinfecdis.2c00558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023]
Abstract
Pathogenic bacteria have devastating impacts on human health as a result of acquired antibiotic resistance and innate tolerance. Every class of our current antibiotic arsenal was initially discovered as growth-inhibiting agents that target actively replicating (individual, free-floating) planktonic bacteria. Bacteria are notorious for utilizing a diversity of resistance mechanisms to overcome the action of conventional antibiotic therapies and forming surface-attached biofilm communities enriched in (non-replicating) persister cells. To address problems associated with pathogenic bacteria, our group is developing halogenated phenazine (HP) molecules that demonstrate potent antibacterial and biofilm-eradicating activities through a unique iron starvation mode of action. In this study, we designed, synthesized, and investigated a focused collection of carbonate-linked HP prodrugs bearing a quinone trigger to target the reductive cytoplasm of bacteria for bioactivation and subsequent HP release. The quinone moiety also contains a polyethylene glycol group, which dramatically enhances the water-solubility properties of the HP-quinone prodrugs reported herein. We found carbonate-linked HP-quinone prodrugs 11, 21-23 to demonstrate good linker stability, rapid release of the active HP warhead following dithiothreitol (reductive) treatment, and potent antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis, and Enterococcus faecalis. In addition, HP-quinone prodrug 21 induced rapid iron starvation in MRSA and S. epidermidis biofilms, illustrating prodrug action within these surface-attached communities. Overall, we are highly encouraged by these findings and believe that HP prodrugs have the potential to address antibiotic resistant and tolerant bacterial infections.
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Affiliation(s)
- Tao Xiao
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Ke Liu
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Qiwen Gao
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Manyun Chen
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Young S Kim
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Shouguang Jin
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Yousong Ding
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Robert W Huigens
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
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Alkhzem AH, Woodman TJ, Blagbrough IS. Design and synthesis of hybrid compounds as novel drugs and medicines. RSC Adv 2022; 12:19470-19484. [PMID: 35865575 PMCID: PMC9257310 DOI: 10.1039/d2ra03281c] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 06/09/2022] [Indexed: 12/13/2022] Open
Abstract
The development of highly effective conjugate chemistry approaches is a way to improve the quality of drugs and of medicines. The aim of this paper is to highlight and review such hybrid compounds and the strategies underpinning their design. A variety of unique hybrid compounds provide an excellent toolkit for novel biological activity, e.g. anticancer and non-viral gene therapy (NVGT), and as templates for killing bacteria and preventing antibiotic drug resistance. First we discuss the anticancer potential of hybrid compounds, containing daunorubicin, benzyl- or tetrahydroisoquinoline-coumarin, and cytotoxic NSAID-pyrrolizidine/indolizine hybrids, then NVGT cationic lipid-based delivery agents, where steroids or long chain fatty acids as the lipid moiety are bound to polyamines as the cationic moiety. These polyamines can be linear as in spermidine or spermine, or on a polycyclic sugar template, aminoglycosides kanamycin and neomycin B, the latter substituted with six amino groups. They are highly efficient for the delivery of both fluorescent DNA and siRNA. Molecular precedents can be found for the design of hybrid compounds in the natural world, e.g., squalamine, the first representative of a previously unknown class of natural antibiotics of animal origin. These polyamine-bile acid (e.g. cholic acid type) conjugates display many exciting biological activities with the bile acids acting as a lipidic region and spermidine as the polycationic region. Analogues of squalamine can act as vectors in NVGT. Their natural role is as antibiotics. Novel antibacterial materials are urgently needed as recalcitrant bacterial infection is a worldwide problem for human health. Ribosome inhibitors founded upon dimers of tobramycin or neomycin, bound as ethers by a 1,6-hexyl linker or a more complex diether-disulfide linker, improved upon the antibiotic activity of aminoglycoside monomers by 20- to 1200-fold. Other hybrids, linked by click chemistry, conjugated ciprofloxacin to neomycin, trimethoprim, or tedizolid, which is now in clinical trials.
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Affiliation(s)
| | - Timothy J Woodman
- Department of Pharmacy and Pharmacology, University of Bath Bath BA2 7AY UK
| | - Ian S Blagbrough
- Department of Pharmacy and Pharmacology, University of Bath Bath BA2 7AY UK
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Liu K, Brivio M, Xiao T, Norwood VM, Kim YS, Jin S, Papagni A, Vaghi L, Huigens RW. Modular Synthetic Routes to Fluorine-Containing Halogenated Phenazine and Acridine Agents That Induce Rapid Iron Starvation in Methicillin-Resistant Staphylococcus aureus Biofilms. ACS Infect Dis 2022; 8:280-295. [PMID: 35089005 PMCID: PMC9004446 DOI: 10.1021/acsinfecdis.1c00402] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
During infection, bacteria use an arsenal of resistance mechanisms to negate antibiotic therapies. In addition, pathogenic bacteria form surface-attached biofilms bearing enriched populations of metabolically dormant persister cells. Bacteria develop resistance in response to antibiotic insults; however, nonreplicating biofilms are innately tolerant to all classes of antibiotics. As such, molecules that can eradicate antibiotic-resistant and antibiotic-tolerant bacteria are of importance. Here, we report modular synthetic routes to fluorine-containing halogenated phenazine (HP) and halogenated acridine (HA) agents with potent antibacterial and biofilm-killing activities. Nine fluorinated phenazines were rapidly accessed through a synthetic strategy involving (1) oxidation of fluorinated anilines to azobenzene intermediates, (2) SNAr with 2-methoxyaniline, and (3) cyclization to phenazines upon treatment with trifluoroacetic acid. Five structurally related acridine heterocycles were synthesized using SNAr and Buchwald-Hartwig approaches. From this focused collection, phenazines 5g, 5h, 5i, and acridine 9c demonstrated potent antibacterial activities against Gram-positive pathogens (MIC = 0.04-0.78 μM). Additionally, 5g and 9c eradicated Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis biofilms with excellent potency (5g, MBEC = 4.69-6.25 μM; 9c, MBEC = 4.69-50 μM). Using real-time quantitative polymerase chain reaction (RT-qPCR), 5g, 5h, 5i, and 9c rapidly induce the transcription of iron uptake biomarkers isdB and sbnC in methicillin-resistant S. aureus (MRSA) biofilms, and we conclude that these agents operate through iron starvation. Overall, fluorinated phenazine and acridine agents could lead to ground-breaking advances in the treatment of challenging bacterial infections.
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Affiliation(s)
- Ke Liu
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Massimiliano Brivio
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - Tao Xiao
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Verrill M. Norwood
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
| | - Young S. Kim
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Shouguang Jin
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - Antonio Papagni
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - Luca Vaghi
- Department of Materials Science, University of Milano-Bicocca, 20125 Milano, Italy
| | - Robert W. Huigens
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development (CNPD3), College of Pharmacy, University of Florida, Gainesville, Florida 32610, United States
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Kaizerman-Kane D, Hadar M, Joseph R, Logviniuk D, Zafrani Y, Fridman M, Cohen Y. Design Guidelines for Cationic Pillar[n]arenes that Prevent Biofilm Formation by Gram-Positive Pathogens. ACS Infect Dis 2021; 7:579-585. [PMID: 33657813 PMCID: PMC8041275 DOI: 10.1021/acsinfecdis.0c00662] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
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Bacterial biofilms are a major threat
to human health, causing
persistent infections that lead to millions of fatalities worldwide
every year. Biofilms also cause billions of dollars of damage annually
by interfering with industrial processes. Recently, cationic pillararenes
were found to be potent inhibitors of biofilm formation in Gram-positive
bacteria. To identify the structural features of pillararenes that
result in antibiofilm activity, we evaluated the activity of 16 cationic
pillar[5]arene derivatives including that of the first cationic water-soluble
pillar[5]arene-based rotaxane. Twelve of the derivatives were potent
inhibitors of biofilm formation by Gram-positive pathogens. Structure
activity analyses of our pillararene derivatives indicated that positively
charged head groups are critical for the observed antibiofilm activity.
Although certain changes in the lipophilicity of the substituents
on the positively charged head groups are tolerated, dramatic elevation
in the hydrophobicity of the substituents or an increase in steric
bulk on these positive charges abolishes the antibiofilm activity.
An increase in the overall positive charge from 10 to 20 did not affect
the activity significantly, but pillararenes with 5 positive charges
and 5 long alkyl chains had reduced activity. Surprisingly, the cavity
of the pillar[n]arene is not essential for the observed activity,
although the macrocyclic structure of the pillar[n]arene core, which
facilitates the clustering of the positive charges, appears important.
Interestingly, the compounds found to be efficient inhibitors of biofilm
formation were nonhemolytic at concentrations that are ∼100-fold
of their MBIC50 (the minimal concentration of a compound
at which at least 50% inhibition of biofilm formation was observed
compared to untreated cells). The structure–activity relationship
guidelines established here pave the way for a rational design of
potent cationic pillar[n]arene-based antibiofilm agents.
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Affiliation(s)
- Dana Kaizerman-Kane
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Maya Hadar
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Roymon Joseph
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Dana Logviniuk
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Yossi Zafrani
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
- Department of Organic Chemistry, Israel Institute for Biological Research, Ness-Ziona 74000, Israel
| | - Micha Fridman
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
| | - Yoram Cohen
- School of Chemistry, Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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Khan F, Pham DTN, Tabassum N, Oloketuyi SF, Kim YM. Treatment strategies targeting persister cell formation in bacterial pathogens. Crit Rev Microbiol 2020; 46:665-688. [DOI: 10.1080/1040841x.2020.1822278] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Fazlurrahman Khan
- Institute of Food Science, Pukyong National University, Busan, Korea
| | - Dung Thuy Nguyen Pham
- Department of Food Science and Technology, Pukyong National University, Busan, Korea
| | - Nazia Tabassum
- Industrial Convergence Bionix Engineering, Pukyong National University, Busan, Korea
| | | | - Young-Mog Kim
- Institute of Food Science, Pukyong National University, Busan, Korea
- Department of Food Science and Technology, Pukyong National University, Busan, Korea
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Salcedo-Sora JE, Kell DB. A Quantitative Survey of Bacterial Persistence in the Presence of Antibiotics: Towards Antipersister Antimicrobial Discovery. Antibiotics (Basel) 2020; 9:E508. [PMID: 32823501 PMCID: PMC7460088 DOI: 10.3390/antibiotics9080508] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/08/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Bacterial persistence to antibiotics relates to the phenotypic ability to survive lethal concentrations of otherwise bactericidal antibiotics. The quantitative nature of the time-kill assay, which is the sector's standard for the study of antibiotic bacterial persistence, is an invaluable asset for global, unbiased, and cross-species analyses. Methods: We compiled the results of antibiotic persistence from antibiotic-sensitive bacteria during planktonic growth. The data were extracted from a sample of 187 publications over the last 50 years. The antibiotics used in this compilation were also compared in terms of structural similarity to fluorescent molecules known to accumulate in Escherichia coli. Results: We reviewed in detail data from 54 antibiotics and 36 bacterial species. Persistence varies widely as a function of the type of antibiotic (membrane-active antibiotics admit the fewest), the nature of the growth phase and medium (persistence is less common in exponential phase and rich media), and the Gram staining of the target organism (persistence is more common in Gram positives). Some antibiotics bear strong structural similarity to fluorophores known to be taken up by E. coli, potentially allowing competitive assays. Some antibiotics also, paradoxically, seem to allow more persisters at higher antibiotic concentrations. Conclusions: We consolidated an actionable knowledge base to support a rational development of antipersister antimicrobials. Persistence is seen as a step on the pathway to antimicrobial resistance, and we found no organisms that failed to exhibit it. Novel antibiotics need to have antipersister activity. Discovery strategies should include persister-specific approaches that could find antibiotics that preferably target the membrane structure and permeability of slow-growing cells.
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Affiliation(s)
- Jesus Enrique Salcedo-Sora
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
| | - Douglas B. Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Biosciences Building, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK;
- Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kgs. Lyngby, Denmark
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Kim SM, Escorbar I, Lee K, Fuchs BB, Mylonakis E, Kim W. Anti-MRSA agent discovery using Caenorhabditis elegans-based high-throughput screening. J Microbiol 2020; 58:431-444. [PMID: 32462486 DOI: 10.1007/s12275-020-0163-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/04/2020] [Accepted: 05/06/2020] [Indexed: 12/17/2022]
Abstract
Staphylococcus aureus is a leading cause of hospital- and community-acquired infections. Despite current advances in antimicrobial chemotherapy, the infections caused by S. aureus remain challenging due to their ability to readily develop resistance. Indeed, antibiotic resistance, exemplified by methicillin-resistant S. aureus (MRSA) is a top threat to global health security. Furthermore, the current rate of antibiotic discovery is much slower than the rate of antibiotic-resistance development. It seems evident that the conventional in vitro bacterial growth-based screening strategies can no longer effectively supply new antibiotics at the rate needed to combat bacterial antibiotic-resistance. To overcome this antibiotic resistance crisis, screening assays based on host-pathogen interactions have been developed. In particular, the free-living nematode Caenorhabditis elegans has been used for drug screening against MRSA. In this review, we will discuss the general principles of the C. elegans-based screening platform and will highlight its unique strengths by comparing it with conventional antibiotic screening platforms. We will outline major hits from high-throughput screens of more than 100,000 small molecules using the C. elegans-MRSA infection assay and will review the mode-of-action of the identified hit compounds. Lastly, we will discuss the potential of a C. elegans-based screening strategy as a paradigm shift screening platform.
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Affiliation(s)
- Soo Min Kim
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Iliana Escorbar
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Kiho Lee
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Beth Burgwyn Fuchs
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, 02903, USA
| | - Wooseong Kim
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul, 03760, Republic of Korea.
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Kuehl R, Morata L, Meylan S, Mensa J, Soriano A. When antibiotics fail: a clinical and microbiological perspective on antibiotic tolerance and persistence of Staphylococcus aureus. J Antimicrob Chemother 2020; 75:1071-1086. [PMID: 32016348 DOI: 10.1093/jac/dkz559] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Staphylococcus aureus is a major human pathogen causing a vast array of infections with significant mortality. Its versatile physiology enables it to adapt to various environments. Specific physiological changes are thought to underlie the frequent failure of antimicrobial therapy despite susceptibility in standard microbiological assays. Bacteria capable of surviving high antibiotic concentrations despite having a genetically susceptible background are described as 'antibiotic tolerant'. In this review, we put current knowledge on environmental triggers and molecular mechanisms of increased antibiotic survival of S. aureus into its clinical context. We discuss animal and clinical evidence of its significance and outline strategies to overcome infections with antibiotic-tolerant S. aureus.
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Affiliation(s)
- Richard Kuehl
- Service of Infectious Diseases, Hospital Clinic of Barcelona, University of Barcelona, IDIBAPS, Barcelona, Spain
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland
| | - Laura Morata
- Service of Infectious Diseases, Hospital Clinic of Barcelona, University of Barcelona, IDIBAPS, Barcelona, Spain
| | - Sylvain Meylan
- Department of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland
- Division de Maladies Infectieuses, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Josep Mensa
- Service of Infectious Diseases, Hospital Clinic of Barcelona, University of Barcelona, IDIBAPS, Barcelona, Spain
| | - Alex Soriano
- Service of Infectious Diseases, Hospital Clinic of Barcelona, University of Barcelona, IDIBAPS, Barcelona, Spain
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Valentine-King MA, Cisneros K, James MO, Huigens RW, Brown MB. Efficacy data of halogenated phenazine and quinoline agents and an NH125 analogue to veterinary mycoplasmas. BMC Vet Res 2020; 16:107. [PMID: 32252763 PMCID: PMC7137434 DOI: 10.1186/s12917-020-02324-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/19/2020] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Mycoplasmas primarily cause respiratory or urogenital tract infections impacting avian, bovine, canine, caprine, murine, and reptilian hosts. In animal husbandry, mycoplasmas cause reduced feed-conversion, decreased egg production, arthritis, hypogalactia or agalactia, increased condemnations, culling, and mortality in some cases. Antibiotics reduce transmission and mitigate clinical signs; however, concerning levels of antibiotic resistance in Mycoplasma gallisepticum and M. capricolum isolates exist. To address these issues, we evaluated the minimum inhibitory concentrations (MICs) of halogenated phenazine and quinoline compounds, an N-arylated NH125 analogue, and triclosan against six representative veterinary mycoplasmas via microbroth or agar dilution methods. Thereafter, we evaluated the minimum bactericidal concentration (MBC) of efficacious drugs. RESULTS We identified several compounds with MICs ≤25 μM against M. pulmonis (n = 5), M. capricolum (n = 4), M. gallisepticum (n = 3), M. alligatoris (n = 3), M. agassizii (n = 2), and M. canis (n = 1). An N-arylated NH125 analogue, compound 21, served as the most efficacious, having a MIC ≤25 μM against all mycoplasmas tested, followed by two quinolines, nitroxoline (compound 12) and compound 20, which were effective against four and three mycoplasma type strains, respectively. Nitroxoline exhibited bactericidal activity among all susceptible mycoplasmas, and compound 21 exhibited bactericidal activity when the MBC was able to be determined. CONCLUSIONS These findings highlight a number of promising agents from novel drug classes with potential applications to treat veterinary mycoplasma infections and present the opportunity to evaluate preliminary pharmacokinetic indices using M. pulmonis in rodents as an animal model of human infection.
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Affiliation(s)
- Marissa A Valentine-King
- Department of Environmental and Global Health, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA.,Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Katherine Cisneros
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida, USA
| | - Margaret O James
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida, USA
| | - Robert W Huigens
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida, USA
| | - Mary B Brown
- Department of Infectious Diseases and Immunology, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA.
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Huigens RW, Abouelhassan Y, Yang H. Phenazine Antibiotic-Inspired Discovery of Bacterial Biofilm-Eradicating Agents. Chembiochem 2019; 20:2885-2902. [PMID: 30811834 PMCID: PMC7325843 DOI: 10.1002/cbic.201900116] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Indexed: 12/19/2022]
Abstract
Bacterial biofilms are surface-attached communities of slow-growing and non-replicating persister cells that demonstrate high levels of antibiotic tolerance. Biofilms occur in nearly 80 % of infections and present unique challenges to our current arsenal of antibiotic therapies, all of which were initially discovered for their abilities to target rapidly dividing, free-floating planktonic bacteria. Bacterial biofilms are credited as the underlying cause of chronic and recurring bacterial infections. Innovative approaches are required to identify new small molecules that operate through bacterial growth-independent mechanisms to effectively eradicate biofilms. One source of inspiration comes from within the lungs of young cystic fibrosis (CF) patients, who often endure persistent Staphylococcus aureus infections. As these CF patients age, Pseudomonas aeruginosa co-infects the lungs and utilizes phenazine antibiotics to eradicate the established S. aureus infection. Our group has taken a special interest in this microbial competition strategy and we are investigating the potential of phenazine antibiotic-inspired compounds and synthetic analogues thereof to eradicate persistent bacterial biofilms. To discover new biofilm-eradicating agents, we have established an interdisciplinary research program involving synthetic medicinal chemistry, microbiology and molecular biology. From these efforts, we have identified a series of halogenated phenazines (HPs) that potently eradicate bacterial biofilms, and future work aims to translate these preliminary findings into ground-breaking clinical advances for the treatment of persistent biofilm infections.
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Affiliation(s)
- Robert W. Huigens
- Department of Medicinal Chemistry; Center for Natural Products Drug Discovery and Development (CNPD3); University of Florida, Gainesville, FL, USA
| | - Yasmeen Abouelhassan
- Department of Medicinal Chemistry; Center for Natural Products Drug Discovery and Development (CNPD3); University of Florida, Gainesville, FL, USA
| | - Hongfen Yang
- Department of Medicinal Chemistry; Center for Natural Products Drug Discovery and Development (CNPD3); University of Florida, Gainesville, FL, USA
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Wu SC, Han F, Song MR, Chen S, Li Q, Zhang Q, Zhu K, Shen JZ. Natural Flavones from Morus alba against Methicillin-Resistant Staphylococcus aureus via Targeting the Proton Motive Force and Membrane Permeability. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:10222-10234. [PMID: 31385700 DOI: 10.1021/acs.jafc.9b01795] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The emergence and rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) critically requires alternative therapeutic options. New antibacterial drugs and strategies are urgently needed to combat MRSA-associated infections. Here, we investigated the antibacterial activity of flavones from Morus alba and the potential mode of action against MRSA. Kuwanon G, kuwanon H, mulberrin, and morusin displayed high efficiency in killing diverse MRSA isolates. On the basis of structure-activity analysis, the cyclohexene-phenyl ketones and isopentenyl groups were critical to increase the membrane permeability and to dissipate the proton motive force. Meanwhile, mechanistic studies further showed that kuwanon G displayed rapid bactericidal activity in vitrowith difficulty in developing drug resistance. Kuwanon G targeted phosphatidylglycerol and cardiolipin in the cytoplasmic membrane through the formation of hydrogen bonds and electrostatic interactions. Additionally, kuwanon G promoted wound healing in a mouse model of MRSA skin infection. In summary, these results indicate that flavones are promising lead compounds to treat MRSA-associated infections through disrupting the proton motive force and membrane permeability.
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Affiliation(s)
- Shuai-Cheng Wu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
- College of Veterinary Medicine , Qingdao Agricultural University , No. 700 Changcheng Road , Qingdao 266109 , Shandong , China
- College of Agriculture and Forestry , Linyi University , No. 1 Gongye Road , Linyi 276000 , Shandong , China
| | - Fei Han
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
| | - Mei-Rong Song
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
| | - Shang Chen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
| | - Qian Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
| | - Qi Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
| | - Kui Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
| | - Jian-Zhong Shen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine , China Agricultural University , No. 2 Yuanmingyuan West Road , Beijing 100193 , China
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Turning the Tide against Antibiotic Resistance by Evaluating Novel, Halogenated Phenazine, Quinoline, and NH125 Compounds against Ureaplasma Species Clinical Isolates and Mycoplasma Type Strains. Antimicrob Agents Chemother 2019; 63:AAC.02265-18. [PMID: 30642935 PMCID: PMC6395908 DOI: 10.1128/aac.02265-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Accepted: 12/23/2018] [Indexed: 02/07/2023] Open
Abstract
Escalating levels of antibiotic resistance in mycoplasmas, particularly macrolide resistance in Mycoplasma pneumoniae and M. genitalium, have narrowed our antibiotic arsenal. Further, mycoplasmas lack a cell wall and do not synthesize folic acid, rendering common antibiotics, such as beta-lactams, vancomycin, sulfonamides, and trimethoprim, of no value. Escalating levels of antibiotic resistance in mycoplasmas, particularly macrolide resistance in Mycoplasma pneumoniae and M. genitalium, have narrowed our antibiotic arsenal. Further, mycoplasmas lack a cell wall and do not synthesize folic acid, rendering common antibiotics, such as beta-lactams, vancomycin, sulfonamides, and trimethoprim, of no value. To address this shortage, we screened nitroxoline, triclosan, and a library of 20 novel, halogenated phenazine, quinoline, and NH125 analogues against Ureaplasma species and M. hominis clinical isolates from urine. We tested a subset of these compounds (n = 9) against four mycoplasma type strains (M. pneumoniae, M. genitalium, M. hominis, and Ureaplasma urealyticum) using a validated broth microdilution or agar dilution method. Among 72 Ureaplasma species clinical isolates, nitroxoline proved most effective (MIC90, 6.25 µM), followed by an N-arylated NH125 analogue (MIC90, 12.5 µM). NH125 and its analogue had significantly higher MICs against U. urealyticum isolates than against U. parvum isolates, whereas nitroxoline did not. Nitroxoline exhibited bactericidal activity against U. parvum isolates but bacteriostatic activity against the majority of U. urealyticum isolates. Among the type strains, the compounds had the greatest activity against M. pneumoniae and M. genitalium, with 8 (80%) and 5 (71.4%) isolates demonstrating MICs of ≤12.5 µM, respectively. Triclosan also exhibited lower MICs against M. pneumoniae and M. genitalium. Overall, we identified a promising range of quinoline, halogenated phenazine, and NH125 compounds that showed effectiveness against M. pneumoniae and M. genitalium and found that nitroxoline, approved for use outside the United States for the treatment of urinary tract infections, and an N-arylated NH125 analogue demonstrated low MICs against Ureaplasma species isolates.
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Abouelhassan Y, Zhang P, Ding Y, Huigens Iii RW. Rapid kill assessment of an N-arylated NH125 analogue against drug-resistant microorganisms. MEDCHEMCOMM 2019; 10:712-716. [PMID: 31191861 DOI: 10.1039/c8md00613j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/27/2019] [Indexed: 01/14/2023]
Abstract
While a number of disinfection techniques are employed in healthcare units, the eradication of drug-resistant microorganisms remains a challenge. We recently reported N-arylated NH125 analogue 1, which demonstrated potent biofilm eradication and antibacterial activities against a panel of drug-resistant pathogens. The broad-spectrum activities observed for 1 along with its rapid eradication of MRSA persister cells suggested that this agent, and related analogues, can serve as disinfectants for antibiotic resistant pathogens in healthcare settings. Here, we report the rapid bactericidal activities of 1 against a panel of exponentially-growing, drug-resistant pathogens. Against MRSA, MRSE, VRE and MDR A. baumannii, 1 eradicated bacterial cells after five minutes when tested at 50 μM (3- to 6-log reduction of CFU per mL). We highlighted the rapid killing activities by demonstrating that 1 eradicates 99.99% of viable MRSA 1707 cells in one minute (50 μM, 4-log reduction of CFU per mL). In addition, 1 rapidly eradicated fungal pathogen C. neoformans in kill kinetic experiments. A solution of 1 demonstrated similar shelf stability to known disinfectant BAC-16 when tested up to 111 days after being stored. Collectively, our data highlights the potential of 1 to be used as a disinfecting agent to prevent healthcare-associated, drug-resistant infections.
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Affiliation(s)
- Yasmeen Abouelhassan
- Department of Medicinal Chemistry , Center for Natural Products Drug Discovery and Development (CNPD3) , College of Pharmacy , University of Florida , Gainesville , FL 32610 , USA .
| | - Peilan Zhang
- Department of Medicinal Chemistry , Center for Natural Products Drug Discovery and Development (CNPD3) , College of Pharmacy , University of Florida , Gainesville , FL 32610 , USA .
| | - Yousong Ding
- Department of Medicinal Chemistry , Center for Natural Products Drug Discovery and Development (CNPD3) , College of Pharmacy , University of Florida , Gainesville , FL 32610 , USA .
| | - Robert W Huigens Iii
- Department of Medicinal Chemistry , Center for Natural Products Drug Discovery and Development (CNPD3) , College of Pharmacy , University of Florida , Gainesville , FL 32610 , USA .
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Basak A, Abouelhassan Y, Kim YS, Norwood VM, Jin S, Huigens RW. Halogenated quinolines bearing polar functionality at the 2-position: Identification of new antibacterial agents with enhanced activity against Staphylococcus epidermidis. Eur J Med Chem 2018; 155:705-713. [PMID: 29936357 DOI: 10.1016/j.ejmech.2018.06.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/15/2018] [Accepted: 06/16/2018] [Indexed: 11/29/2022]
Abstract
Antibiotic-resistant bacteria and surface-attached biofilms continue to play a significant role in human health and disease. Innovative strategies are needed to identify new therapeutic leads to tackle infections of drug-resistant and tolerant bacteria. We synthesized a focused library of 14 new halogenated quinolines to investigate the impact of ClogP values on antibacterial and biofilm-eradication activities. During these investigations, we found select polar appendages at the 2-position of the HQ scaffold were more well-tolerated than others. We were delighted to see multiple compounds display enhanced activities against the major human pathogen S. epidermidis. In particular, HQ 2 (ClogP = 3.44) demonstrated enhanced activities against MRSE 35984 planktonic cells (MIC = 0.59 μM) compared to MRSA and VRE strains in addition to potent MRSE biofilm eradication activities (MBEC = 2.35 μM). Several of the halogenated quinolines identified here reported low cytotoxicity against HeLa cells with minimal hemolytic activity against red blood cells. We believe that halogenated quinoline small molecules could play an important role in the development of next-generation antibacterial therapeutics capable of targeting and eradicating biofilm-associated infections.
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Affiliation(s)
- Akash Basak
- Department of Chemistry, University of Florida, United States
| | - Yasmeen Abouelhassan
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery & Development (CNPD3), College of Pharmacy, University of Florida, United States
| | - Young S Kim
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, United States
| | - Verrill M Norwood
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery & Development (CNPD3), College of Pharmacy, University of Florida, United States
| | - Shouguang Jin
- Department of Molecular Genetics & Microbiology, College of Medicine, University of Florida, United States
| | - Robert W Huigens
- Department of Chemistry, University of Florida, United States; Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery & Development (CNPD3), College of Pharmacy, University of Florida, United States.
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Fighting bacterial persistence: Current and emerging anti-persister strategies and therapeutics. Drug Resist Updat 2018; 38:12-26. [DOI: 10.1016/j.drup.2018.03.002] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/07/2018] [Accepted: 03/25/2018] [Indexed: 01/13/2023]
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Kim W, Hendricks GL, Tori K, Fuchs BB, Mylonakis E. Strategies against methicillin-resistant Staphylococcus aureus persisters. Future Med Chem 2018; 10:779-794. [PMID: 29569952 PMCID: PMC6077763 DOI: 10.4155/fmc-2017-0199] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/01/2017] [Indexed: 12/21/2022] Open
Abstract
Chronic Staphylococcus aureus infections are complicated by frequent relapses not only from the development of drug resistance to conventional antibiotics, but also through the formation of persister bacterial cells. Bacterial persisters are in a transient, metabolically inactive state, making conventional antibiotics that target essential cellular growth processes ineffective, resulting in high clinical failure rates of antibiotic chemotherapy. The development of new antibiotics against persistent S. aureus is an urgent issue. Over the last decade, new strategies to identify S. aureus persister-active compounds have been proposed. This review summarizes the proposed targets, antipersister compounds and innovative methods that may augment conventional antibiotics against S. aureus persisters. The reviewed antipersister strategies can be summarized as two broad categories; directly targeting growth-independent targets and potentiating existing, ineffective antibiotics by aiding uptake or accessibility.
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Affiliation(s)
- Wooseong Kim
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA
| | - Gabriel L Hendricks
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA
| | - Katerina Tori
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA
| | - Beth B Fuchs
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA
| | - Eleftherios Mylonakis
- Division of Infectious Diseases, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI 02903, USA
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Basak A, Abouelhassan Y, Zuo R, Yousaf H, Ding Y, Huigens RW. Antimicrobial peptide-inspired NH125 analogues: bacterial and fungal biofilm-eradicating agents and rapid killers of MRSA persisters. Org Biomol Chem 2018; 15:5503-5512. [PMID: 28534905 DOI: 10.1039/c7ob01028a] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
During microbial infection, antimicrobial peptides are utilized by the immune response to rapidly eradicate microbial pathogens through the destruction of cellular membranes. Inspired by antimicrobial peptides, quaternary ammonium cationic (QAC) compounds have emerged as agents capable of destroying bacterial membranes leading to rapid bacterial death, including the eradication of persistent, surface-attached bacterial biofilms. NH125, an imidazolium cation with a sixteen membered fatty tail, was recently reported to eradicate persister cells and was our starting point for the development of novel antimicrobial agents. Here, we describe the design, chemical synthesis and biological investigations of a collection of 30 diverse NH125 analogues which provided critical insights into structural features that are important for antimicrobial activities in this class. From these studies, multiple NH125 analogues were identified to possess potent antibacterial and antifungal activities, eradicate both bacterial and fungal biofilms and rapidly eradicate MRSA persister cells in stationary phase. NH125 analogues also demonstrated more rapid persister cell killing activities against MRSA when tested alongside a panel of diverse membrane-active agents, including BAC-16 and daptomycin. NH125 analogues could have a significant impact on persister- and biofilm-related problems in numerous biomedical applications.
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Affiliation(s)
- Akash Basak
- Department of Chemistry, University of Florida, Gainesville, FL 32610, USA.
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