1
|
Stackpole BJ, Fredericksen JM, Brasch NE. Exploring the potential of the vitamin B 12 derivative azidocobalamin to undergo Huisgen 1,3-dipolar azide-alkyne cycloaddition reactions. J Inorg Biochem 2024; 254:112504. [PMID: 38412777 DOI: 10.1016/j.jinorgbio.2024.112504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/08/2024] [Accepted: 02/09/2024] [Indexed: 02/29/2024]
Abstract
There is considerable interest in using the metalloprotein cofactor vitamin B12 as a vehicle to deliver drugs and diagnostic agents into mammalian or bacterial cells by exploiting the B12-specific active uptake pathways. Conjugation of the cargo via the β-axial site or the 5'-OH of the ribose of the nucleotide are the most desirable sites, to maximise intracellular uptake. Herein we show the potential of conjugation at the beta-azido ligand of the vitamin B12 derivative azidocobalamin via a click-type azide-alkyne 1,3-dipolar cycloaddition (Huisgen cycloaddition) reaction. Reacting azidocobalamin with dimethyl acetylenedicarboxylate at 40 °C results in essentially stoichiometric conversion of azidocobalamin to the corresponding triazolato complex. The stability of the complex as a function of pH and in the presence of cyanide were investigated. The complex is stable in pD 7.0 phosphate buffer for 24 h. The rate of beta-axial ligand substitution was found to be one order of magnitude slower for the triazolatocobalamin complex compared with azidocobalamin.
Collapse
Affiliation(s)
- Ben J Stackpole
- School of Science, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand; The Dodd-Walls Centre for Quantum and Photonic Technologies, Dunedin 9054, New Zealand; The Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland 1142, New Zealand
| | - Jessica M Fredericksen
- School of Science, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand; The Dodd-Walls Centre for Quantum and Photonic Technologies, Dunedin 9054, New Zealand; The Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland 1142, New Zealand
| | - Nicola E Brasch
- School of Science, Auckland University of Technology, Private Bag 92006, Auckland 1142, New Zealand; The Dodd-Walls Centre for Quantum and Photonic Technologies, Dunedin 9054, New Zealand; The Maurice Wilkins Centre for Molecular Biodiscovery, Private Bag 92019, Auckland 1142, New Zealand.
| |
Collapse
|
2
|
Tsylents U, Siekierska I, Trylska J. Peptide nucleic acid conjugates and their antimicrobial applications-a mini-review. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:533-544. [PMID: 37610696 PMCID: PMC10618302 DOI: 10.1007/s00249-023-01673-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 08/24/2023]
Abstract
Peptide nucleic acid (PNA) is a nucleic acid mimic with high specificity and binding affinity to natural DNA or RNA, as well as resistance to enzymatic degradation. PNA sequences can be designed to selectively silence gene expression, which makes PNA a promising tool for antimicrobial applications. However, the poor membrane permeability of PNA remains the main limiting factor for its applications in cells. To overcome this obstacle, PNA conjugates with different molecules have been developed. This mini-review focuses on covalently linked conjugates of PNA with cell-penetrating peptides, aminosugars, aminoglycoside antibiotics, and non-peptidic molecules that were tested, primarily as PNA carriers, in antibacterial and antiviral applications. The chemistries of the conjugation and the applied linkers are also discussed.
Collapse
Affiliation(s)
- Uladzislava Tsylents
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097, Warsaw, Poland
| | - Izabela Siekierska
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097, Warsaw, Poland
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097, Warsaw, Poland.
| |
Collapse
|
3
|
Almeida MC, da Costa PM, Sousa E, Resende DISP. Emerging Target-Directed Approaches for the Treatment and Diagnosis of Microbial Infections. J Med Chem 2023; 66:32-70. [PMID: 36586133 DOI: 10.1021/acs.jmedchem.2c01212] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
With the rising levels of drug resistance, developing efficient antimicrobial therapies has become a priority. A promising strategy is the conjugation of antibiotics with relevant moieties that can potentiate their activity by target-directing. The conjugation of siderophores with antibiotics allows them to act as Trojan horses by hijacking the microorganisms' highly developed iron transport systems and using them to carry the antibiotic into the cell. Through the analysis of relevant examples of the past decade, this Perspective aims to reveal the potential of siderophore-antibiotic Trojan horses for the treatment of infections and the role of siderophores in diagnostic techniques. Other conjugated molecules will be the subject of discussion, namely those involving vitamin B12, carbohydrates, and amino acids, as well as conjugated compounds targeting protein degradation and β-lactamase activated prodrugs.
Collapse
Affiliation(s)
- Mariana C Almeida
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, FFUP - Faculdade de Farmácia, Universidade do Porto, Rua de Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal.,CIIMAR- Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Paulo M da Costa
- CIIMAR- Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal.,ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Emília Sousa
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, FFUP - Faculdade de Farmácia, Universidade do Porto, Rua de Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal.,CIIMAR- Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Diana I S P Resende
- Laboratório de Química Orgânica e Farmacêutica, Departamento de Ciências Químicas, FFUP - Faculdade de Farmácia, Universidade do Porto, Rua de Jorge de Viterbo Ferreira 228, 4050-313 Porto, Portugal.,CIIMAR- Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| |
Collapse
|
4
|
Tinsley IC, Borner T, Swanson ML, Chepurny OG, Doebley SA, Kamat V, Sweet IR, Holz GG, Hayes MR, De Jonghe BC, Doyle RP. Synthesis, Optimization, and Biological Evaluation of Corrinated Conjugates of the GLP-1R Agonist Exendin-4. J Med Chem 2021; 64:3479-3492. [PMID: 33677970 PMCID: PMC8279408 DOI: 10.1021/acs.jmedchem.1c00185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
![]()
Corrination
is the conjugation of a corrin ring containing molecule,
such as vitamin B12 (B12) or B12 biosynthetic precursor
dicyanocobinamide (Cbi), to small molecules, peptides, or proteins
with the goal of modifying pharmacology. Recently, a corrinated GLP-1R
agonist (GLP-1RA) exendin-4 (Ex4) has been shown in vivo to have reduced penetration into the central nervous system relative
to Ex4 alone, producing a glucoregulatory GLP-1RA devoid of anorexia
and emesis. The study herein was designed to optimize the lead conjugate
for GLP-1R agonism and binding. Two specific conjugation sites were
introduced in Ex4, while also utilizing various linkers, so that it
was possible to identify Cbi conjugates of Ex4 that exhibit improved
binding and agonist activity at the GLP-1R. An optimized conjugate
(22), comparable with Ex4, was successfully screened
and subsequently assayed for insulin secretion in rat islets and in vivo in shrews for glucoregulatory and emetic behavior,
relative to Ex4.
Collapse
Affiliation(s)
- Ian C Tinsley
- Department of Chemistry, Syracuse University, 111 College Place, Syracuse, New York 13244, United States
| | - Tito Borner
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, Pennsylvania 19104, United States
| | - MacKenzie L Swanson
- Department of Chemistry, Syracuse University, 111 College Place, Syracuse, New York 13244, United States
| | - Oleg G Chepurny
- Department of Medicine, State University of New York, Upstate Medical University, Syracuse, New York 13210, United States
| | - Sarah A Doebley
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, Pennsylvania 19104, United States
| | - Varun Kamat
- Department of Medicine, University of Washington, Medicine Diabetes Institute, Seattle, Washington 98109, United States
| | - Ian R Sweet
- Department of Medicine, University of Washington, Medicine Diabetes Institute, Seattle, Washington 98109, United States
| | - George G Holz
- Department of Medicine, State University of New York, Upstate Medical University, Syracuse, New York 13210, United States
| | - Matthew R Hayes
- Department of Psychiatry, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
| | - Bart C De Jonghe
- Department of Biobehavioral Health Sciences, University of Pennsylvania, School of Nursing, Philadelphia, Pennsylvania 19104, United States
| | - Robert P Doyle
- Department of Chemistry, Syracuse University, 111 College Place, Syracuse, New York 13244, United States.,Department of Medicine, State University of New York, Upstate Medical University, Syracuse, New York 13210, United States
| |
Collapse
|
5
|
Pieńko T, Czarnecki J, Równicki M, Wojciechowska M, Wierzba AJ, Gryko D, Bartosik D, Trylska J. Vitamin B 12-peptide nucleic acids use the BtuB receptor to pass through the Escherichia coli outer membrane. Biophys J 2021; 120:725-737. [PMID: 33453274 DOI: 10.1016/j.bpj.2021.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 12/30/2020] [Accepted: 01/07/2021] [Indexed: 12/11/2022] Open
Abstract
Short modified oligonucleotides that bind in a sequence-specific way to messenger RNA essential for bacterial growth could be useful to fight bacterial infections. One such promising oligonucleotide is peptide nucleic acid (PNA), a synthetic DNA analog with a peptide-like backbone. However, the limitation precluding the use of oligonucleotides, including PNA, is that bacteria do not import them from the environment. We have shown that vitamin B12, which most bacteria need to take up for growth, delivers PNAs to Escherichia coli cells when covalently linked with PNAs. Vitamin B12 enters E. coli via a TonB-dependent transport system and is recognized by the outer-membrane vitamin B12-specific BtuB receptor. We engineered the E. coli ΔbtuB mutant and found that transport of the vitamin B12-PNA conjugate requires BtuB. Thus, the conjugate follows the same route through the outer membrane as taken by free vitamin B12. From enhanced sampling all-atom molecular dynamics simulations, we determined the mechanism of conjugate permeation through BtuB. BtuB is a β-barrel occluded by its luminal domain. The potential of mean force shows that conjugate passage is unidirectional and its movement into the BtuB β-barrel is energetically favorable upon luminal domain unfolding. Inside BtuB, PNA extends making its permeation mechanically feasible. BtuB extracellular loops are actively involved in transport through an induced-fit mechanism. We prove that the vitamin B12 transport system can be hijacked to enable PNA delivery to E. coli cells.
Collapse
Affiliation(s)
- Tomasz Pieńko
- Centre of New Technologies, University of Warsaw, Warsaw, Poland; Department of Drug Chemistry, Faculty of Pharmacy with the Laboratory Medicine Division, Medical University of Warsaw, Warsaw, Poland.
| | - Jakub Czarnecki
- Faculty of Biology, University of Warsaw, Warsaw, Poland; Bacterial Genome Plasticity, Department of Genomes and Genetics, Institut Pasteur, Paris, France
| | - Marcin Równicki
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | | | | | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | | | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
| |
Collapse
|
6
|
Abstract
Vitamin B12 (cobalamin, Cbl) is an essential nutrient for all mammals and some bacteria. From a chemical point of view, it is a highly functionalized molecule, which enables conjugation at multiple positions and attachment of various cargoes. Both mammalian and bacterial cells have developed a specific transport pathway for the uptake of vitamin B12, and as a consequence, cobalamin is an attractive candidate for the delivery of biologically relevant molecules into cells. Indeed, hybrid molecules containing vitamin B12 in their structure have found various applications in medicinal chemistry, diagnostics, and biological sciences.Herein, we describe synthetic strategies toward the synthesis of vitamin B12 conjugates with peptide nucleic acid (PNA ) oligomers. Such short-modified oligonucleotides targeted at bacterial DNA or RNA can act as antibacterial agents if efficiently taken up by bacterial cells. The uptake of such oligonucleotides is hindered by the bacterial cell envelope, but vitamin B12 was found to efficiently deliver antisense PNA into Escherichia coli and Salmonella Typhimurium cells. This paves the way to the use of vitamin B12-PNA conjugates in antibacterial and diagnostic applications.Vitamin B12-PNA conjugates can be prepared via copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) that gives access to covalently linked hybrids or via connecting both building blocks by reduction-sensitive disulfide bridge. Both approaches require prior modification of vitamin B12 by incorporation of the azide moiety or via transformation of the native functional group into a moiety reactive toward thiols. Conjugation of vitamin B12 with PNA-tagged substrates efficiently furnishes designed conjugates.
Collapse
Affiliation(s)
| | | | - Joanna Trylska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland.
| |
Collapse
|
7
|
Volpi S, Cancelli U, Neri M, Corradini R. Multifunctional Delivery Systems for Peptide Nucleic Acids. Pharmaceuticals (Basel) 2020; 14:14. [PMID: 33375595 PMCID: PMC7823687 DOI: 10.3390/ph14010014] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The number of applications of peptide nucleic acids (PNAs)-oligonucleotide analogs with a polyamide backbone-is continuously increasing in both in vitro and cellular systems and, parallel to this, delivery systems able to bring PNAs to their targets have been developed. This review is intended to give to the readers an overview on the available carriers for these oligonucleotide mimics, with a particular emphasis on newly developed multi-component- and multifunctional vehicles which boosted PNA research in recent years. The following approaches will be discussed: (a) conjugation with carrier molecules and peptides; (b) liposome formulations; (c) polymer nanoparticles; (d) inorganic porous nanoparticles; (e) carbon based nanocarriers; and (f) self-assembled and supramolecular systems. New therapeutic strategies enabled by the combination of PNA and proper delivery systems are discussed.
Collapse
Affiliation(s)
| | | | | | - Roberto Corradini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy; (S.V.); (U.C.); (M.N.)
| |
Collapse
|
8
|
Zhao S, Wang ZP, Wen X, Li S, Wei G, Guo J, He Y. Synthesis of Vitamin B 12-Antibiotic Conjugates with Greatly Improved Activity against Gram-Negative Bacteria. Org Lett 2020; 22:6632-6636. [PMID: 32806210 DOI: 10.1021/acs.orglett.0c02403] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
There is an urgent need to discover new antibiotics and improve the efficacy of known antibiotics against Gram-negative bacteria. "Trojan horse" conjugates are novel and promising antibiotics. Herein we report the design and synthesis of vitamin-B12-ampicillin conjugates, which exhibited more than 500 times improved activity against Escherichia coli compared with ampicillin itself. Our studies demonstrate that the vitamin-B12 uptake pathway could be employed for effective antibiotic delivery and efficacy enhancement.
Collapse
Affiliation(s)
- Sheng Zhao
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P.R. China
| | - Zhi-Peng Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Xumei Wen
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P.R. China
| | - Siyu Li
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P.R. China
| | - Guoxing Wei
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P.R. China
| | - Jian Guo
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P.R. China
| | - Yun He
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, P.R. China
| |
Collapse
|
9
|
Extracellular loops of BtuB facilitate transport of vitamin B12 through the outer membrane of E. coli. PLoS Comput Biol 2020; 16:e1008024. [PMID: 32609716 PMCID: PMC7360065 DOI: 10.1371/journal.pcbi.1008024] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/14/2020] [Accepted: 06/08/2020] [Indexed: 02/06/2023] Open
Abstract
Vitamin B12 (or cobalamin) is an enzymatic cofactor essential both for mammals and bacteria. However, cobalamin can be synthesized only by few microorganisms so most bacteria need to take it up from the environment through the TonB-dependent transport system. The first stage of cobalamin import to E. coli cells occurs through the outer-membrane receptor called BtuB. Vitamin B12 binds with high affinity to the extracellular side of the BtuB protein. BtuB forms a β-barrel with inner luminal domain and extracellular loops. To mechanically allow for cobalamin passage, the luminal domain needs to partially unfold with the help of the inner-membrane TonB protein. However, the mechanism of cobalamin permeation is unknown. Using all-atom molecular dynamics, we simulated the transport of cobalamin through the BtuB receptor embedded in an asymmetric and heterogeneous E. coli outer-membrane. To enhance conformational sampling of the BtuB loops, we developed the Gaussian force-simulated annealing method (GF-SA) and coupled it with umbrella sampling. We found that cobalamin needs to rotate in order to permeate through BtuB. We showed that the mobility of BtuB extracellular loops is crucial for cobalamin binding and transport and resembles an induced-fit mechanism. Loop mobility depends not only on the position of cobalamin but also on the extension of luminal domain. We provided atomistic details of cobalamin transport through the BtuB receptor showing the essential role of the mobility of BtuB extracellular loops. A similar TonB-dependent transport system is used also by many other compounds, such as haem and siderophores, and importantly, can be hijacked by natural antibiotics. Our work could have implications for future delivery of antibiotics to bacteria using this transport system.
Collapse
|
10
|
Antibacterial Peptide Nucleic Acids-Facts and Perspectives. Molecules 2020; 25:molecules25030559. [PMID: 32012929 PMCID: PMC7038079 DOI: 10.3390/molecules25030559] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 12/13/2022] Open
Abstract
Antibiotic resistance is an escalating, worldwide problem. Due to excessive use of antibiotics, multidrug-resistant bacteria have become a serious threat and a major global healthcare problem of the 21st century. This fact creates an urgent need for new and effective antimicrobials. The common strategies for antibiotic discovery are based on either modifying existing antibiotics or screening compound libraries, but these strategies have not been successful in recent decades. An alternative approach could be to use gene-specific oligonucleotides, such as peptide nucleic acid (PNA) oligomers, that can specifically target any single pathogen. This approach broadens the range of potential targets to any gene with a known sequence in any bacterium, and could significantly reduce the time required to discover new antimicrobials or their redesign, if resistance arises. We review the potential of PNA as an antibacterial molecule. First, we describe the physicochemical properties of PNA and modifications of the PNA backbone and nucleobases. Second, we review the carriers used to transport PNA to bacterial cells. Furthermore, we discuss the PNA targets in antibacterial studies focusing on antisense PNA targeting bacterial mRNA and rRNA.
Collapse
|
11
|
Hansen AM, Bonke G, Hogendorf WFJ, Björkling F, Nielsen J, Kongstad KT, Zabicka D, Tomczak M, Urbas M, Nielsen PE, Franzyk H. Microwave-assisted solid-phase synthesis of antisense acpP peptide nucleic acid-peptide conjugates active against colistin- and tigecycline-resistant E. coli and K. pneumoniae. Eur J Med Chem 2019; 168:134-145. [PMID: 30807888 DOI: 10.1016/j.ejmech.2019.02.024] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 02/05/2019] [Accepted: 02/07/2019] [Indexed: 11/26/2022]
Abstract
Recent discovery of potent antibacterial antisense PNA-peptide conjugates encouraged development of a fast and efficient synthesis protocol that facilitates structure-activity studies. The use of an Fmoc/Boc protection scheme for both PNA monomers and amino acid building blocks in combination with microwave-assisted solid-phase synthesis proved to be a convenient procedure for continuous assembly of antisense PNA-peptide conjugates. A validated antisense PNA oligomer (CTCATACTCT; targeting mRNA of the acpP gene) was linked to N-terminally modified drosocin (i.e., RXR-PRPYSPRPTSHPRPIRV; X = aminohexanoic acid) or to a truncated Pip1 peptide (i.e., RXRRXR-IKILFQNRRMKWKK; X = aminohexanoic acid), and determination of the antibacterial effects of the resulting conjugates allowed assessment of the influence of different linkers as well as differences between the L- and D-forms of the peptides. The drosocin-derived compound without a linker moiety exhibited highest antibacterial activity against both wild-type Escherichia coli and Klebsiella pneumoniae (MICs in the range 2-4 μg/mL ∼ 0.3-0.7 μM), while analogues displaying an ethylene glycol (eg1) moiety or a polar maleimide linker also possessed activity toward wild-type K. pneumoniae (MICs of 4-8 μg/mL ∼ 0.6-1.3 μM). Against two colistin-resistant E. coli strains the linker-deficient compound proved most potent (with MICs in the range 2-4 μg/mL ∼ 0.3-0.7 μM). The truncated all-L Pip1 peptide had moderate inherent activity against E. coli, and this was unaltered or reduced upon conjugation to the antisense PNA oligomer. By contrast, this peptide was 8-fold less potent against K. pneumoniae, but in this case some PNA-peptide conjugates exhibited potent antisense activity (MICs of 2-8 μg/mL ∼ 0.3-1.2 μM). Most interestingly, the antibacterial activity of the D-form peptide itself was 2- to 16-fold higher than that of the L-form, even for the colistin- and tigecycline-resistant E. coli strains (MIC of 1-2 μg/mL ∼ 0.25-0.5 μM). Low activity was found for conjugates with a two-mismatch PNA sequence corroborating an antisense mode of action. Conjugates containing a D-form peptide were also significantly less active. In conclusion, we have designed and synthesized antisense PNA-drosocin conjugates with potent antibacterial activity against colistin- and tigecycline-resistant E. coli and K. pneumonia without concomitant hemolytic properties. In addition, a truncated D-form of Pip1 was identified as a peptide exhibiting potent activity against both wild-type and multidrug-resistant E. coli, P. aeruginosa, and A. baumannii (MICs within the range 1-4 μg/mL ∼ 0.25-1 μM) as well as toward wild-type Staphylococcus aureus (MIC of 2-4 μg/mL ∼ 0.5-1.0 μM).
Collapse
Affiliation(s)
- Anna Mette Hansen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark
| | - Gitte Bonke
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark
| | - Wouter Frederik Johan Hogendorf
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark
| | - Fredrik Björkling
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark
| | - John Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark
| | - Kenneth T Kongstad
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark
| | - Dorota Zabicka
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, ul. Chełmska 30/34, 00-725, Warsaw, Poland
| | - Magdalena Tomczak
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, ul. Chełmska 30/34, 00-725, Warsaw, Poland
| | - Malgorzata Urbas
- Department of Epidemiology and Clinical Microbiology, National Medicines Institute, ul. Chełmska 30/34, 00-725, Warsaw, Poland
| | - Peter E Nielsen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2100, Denmark
| | - Henrik Franzyk
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 162, DK-2100, Denmark.
| |
Collapse
|