Basic peptide-morpholino oligomer conjugate that is very effective in killing bacteria by gene-specific and nonspecific modes

Abstract

Basic peptides covalently linked to nucleic acids, or chemically modified nucleic acids, enable the insertion of such a conjugate into bacteria grown in liquid medium and mammalian cells in tissue culture. A unique peptide, derived from human T cells, has been employed in a chemical synthesis to make a conjugate with a morpholino oligonucleotide. This new conjugate is at least 10- to 100-fold more effective than previous peptides used in altering the phenotype of host bacteria if the external guide sequence methodology is employed in these experiments. Bacteria with target genes expressing chloramphenicol resistance, penicillin resistance, or gyrase A function can effectively be reduced in their expression and the host cells killed. Several bacteria are susceptible to this treatment, which has a broad range of potency. The loss in viability of bacteria is not due only to complementarity with a target RNA and the action of RNase P, but also to a non-gene-specific tight binding of the complexed nontargeted RNA to the basic polypeptide-morpholino oligonucleotide.

Targeting protein translation, RNA splicing, and degradation by morpholino-based conjugates in Plasmodium falciparum

“…The sequence of the MO thereby decides the fate of the endogenous transcript. For example, MOs with External Guide Sequence (EGS) conjugated to peptides (PPMOs) have been designed to target essential genes of several pathogenic bacteria and have displayed strong antibacterial activity (10)(11)(12)(13). Similarly, PPMOs targeting the P. falciparum PfGyrA and PfPAT RNAs for RNase P-mediated cleavage inhibit parasite growth in the low micromolar range (4,(14)(15)(16).…”

Peptide Conjugated Phosphorodiamidate Morpholino Oligomers Increase Survival of Mice Challenged with AmesBacillus anthracis

“…This suggests that the efficacy of PPMOs may not be entirely gene specific. Off target or nonspecific effects of PPMOs have also been observed in vitro with E. coli (Wesolowski et al, 2011) and Acinetobacter lwoffii (Geller, unpublished data), and in vivo with Burkholderia multivorans (Greenberg et al, 2010). Some of this nonspecific effect may be due to partial complementarity of scrambled sequence controls to other genes (Wesolowski et al, 2011).…”

Combined effect of a peptide–morpholino oligonucleotide conjugate and a cell-penetrating peptide as an antibiotic

“…The resident and ubiquitous RNase P then cleaves the complex, thereby rendering the pathogenic RNA inactive (9). In an investigation of the PMO that relies on EGS technology for its use, both gene-specific and non-gene-specific effects had been ascribed to this and similar compounds (1). Gel filtration purification yielded the PMO and, separately, unreacted CPP and MO.…”

“…EGS technology | gram-negative bacteria | gram-positive bacteria | RNase P M orpholino oligonucleotides (MOs) covalently linked with a cell-penetrating peptide (CPP) can be used as antibiotics (1). Such compounds are potent in the variety of cells they attack (both Gram-positive and Gram-negative bacteria) but are somewhat less efficient than conventional antibiotics today in terms of the concentrations used to kill cells.…”