Antisense inhibition of gene expression and growth in gram-negative bacteria by cell-penetrating peptide conjugates of peptide nucleic acids targeted to rpoD gene

Antisense Antibacterials: From Proof-Of-Concept to Therapeutic Perspectives

“…Results from our lab (unpublished and Bai & et al, 2012b) gives the first proof-of-principle evidence for exploring and identifying bacterial RNAP σ 70 as an antibacterial target by antisense strategy. We identified a conserved target sequence within the native rpoD mRNA start codon region, and a cell penetrating peptide (RXR) 4 XB conjugated 10-mer peptide nucleic acid was developed for potent sequence-selective bacteriocidal antisense effect against six pathogenic gram-negative species, including Escherichia coli, Salmonella enterica, Klebsiella pneumoniae, Shigella flexneri, Citrobacter freundii, and Enterobacter cloacae.…”

“…The excelent stability of PNA-CPP conjugates has been confirmed for a 48h period at 37℃ in rat's plasma (Bai & et al, 2012b). However, there has been no report of in vivo tissue distribution and pharmacokinetics properties of CPP-PNA conjugates targeting bacterial genes.…”

“…Evidence shows that the efficacy of CPPs differs according to bacterial species, and the underlying mechanisms are still unclear. Inadequate information has been accumulated from sporadic studies, e.g., (KFF Bai & et al, 2012b). Following studies demonstrated that gram positive bacteria Bacillus subtilis and Corynebacterium efficiens exhibit increased susceptibility to CPP-PNAs, but in contrast, the gram-negative bacterium Ralstonia eutropha was not affected by addition of CPP-PNA.…”

Peptide nucleic acid antisense oligomers open an avenue for developing novel antibacterial molecules

“…Years later, a separate study exhibited that PNA oligomer in conjugation with KFFKFFKFFK peptide is also able to inhibit the growth of wild type E. coli strain [10]. Since then, numerous studies have reported the antibacterial activity of peptide-PNA conjugates in different bacterial strains, Campylobacter jejuni, Staphylococcus aureus, Mycobacterium smegmatis, Brucella suis, Pseudomonas aeruginosa, Klebsiella pneumonia, E. coli, Shigella flexneri, and Streptococcus pyogenes [11][12][13][14][15][16][17][18][19][20].…”

“…It has been shown that PNA or Morpholino antisense oligomers in conjugation with (KFF)3K, (RX)6B-, (RXR)4XB-, and (RFR)4XB peptides are able to eliminate bacterial infection in mice [18,[24][25][26]. Furthermore, it is also possible that the peptides which efficiently transport PNA oligomers in mammalian cells may also be capable of transporting PNA oligomers in bacteria [27,28].…”