title: Tetrahedral DNA Nanoparticle Vector for Intracellular Delivery of Targeted Peptide Nucleic Acid Antisense Agents to Restore Antibiotic Sensitivity in Cefotaxime-Resistant Escherichia coli.
abstract: The bacterial cell wall presents a barrier to the uptake of unmodified synthetic antisense oligonucleotides, such as peptide nucleic acids, and so is one of the greatest obstacles to the development of their use as therapeutic anti-bacterial agents. Cell-penetrating peptides have been covalently attached to antisense agents, to facilitate penetration of the bacterial cell wall and deliver their cargo into the cytoplasm. Although they are an effective vector for antisense oligonucleotides, they are not specific for bacterial cells and can exhibit growth inhibitory properties at higher doses. Using a bacterial cell growth assay in the presence of cefotaxime (CTX 16 mg/L), we have developed and evaluated a self-assembling non-toxic DNA tetrahedron nanoparticle vector incorporating a targeted anti-blaCTX-M-group 1antisense peptide nucleic acid (PNA4) in its structure for penetration of the bacterial cell wall. A dose-dependent CTX potentiating effect was observed when PNA4 (0-40 μM) was incorporated into the structure of a DNA tetrahedron vector. The minimum inhibitory concentration (to CTX) of an Escherichia coli field isolate harboring a plasmid carrying blaCTX-M-3was reduced from 35 to 16 mg/L in the presence of PNA4 carried by the DNA tetrahedron vector (40 μM), contrasting with no reduction in MIC in the presence of PNA4 alone. No growth inhibitory effects of the DNA tetrahedron vector alone were observed.
authors.affiliation: 1 Bacteriology Department, Animal and Plant Health Agency , Addlestone, Surrey, United Kingdom .|2 Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London , Surrey, United Kingdom .
authors.forename: John Benedict
authors.initials: JB
authors.lastname: Readman
authors.affiliation: 2 Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway-University of London , Surrey, United Kingdom .
authors.forename: George
authors.initials: G
authors.lastname: Dickson
authors.affiliation: 1 Bacteriology Department, Animal and Plant Health Agency , Addlestone, Surrey, United Kingdom .
authors.forename: Nick G
authors.initials: NG
authors.lastname: Coldham
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002439:Cefotaxime / Q000494:pharmacology; D002473:Cell Wall / Q000737:chemistry; D057846:Cell-Penetrating Peptides / Q000494:pharmacology*; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D016503:Drug Delivery Systems / Q000639:trends; D004926:Escherichia coli / Q000187:drug effects*; D029968:Escherichia coli Proteins / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D053758:Nanoparticles / Q000737:chemistry; D016376:Oligonucleotides, Antisense / Q000737:chemistry / Q000494:pharmacology*; D020135:Peptide Nucleic Acids / Q000737:chemistry / Q000494:pharmacology*; D010957:Plasmids / Q000737:chemistry; D001618:beta-Lactamases / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D057846:Cell-Penetrating Peptides; D004277:DNA, Single-Stranded; D029968:Escherichia coli Proteins; D016376:Oligonucleotides, Antisense; D020135:Peptide Nucleic Acids; D001618:beta-Lactamases; C000602253:beta-lactamase CTX-M, E coli; D002439:Cefotaxime
keywords: CTX-M; DNA nanoparticle vector; E. coli; PNA; restore antibiotic susceptibility