Targeting Bacterial Adenylate Kinase mRNA with a Chimeric Antisense Oligonucleotide for Rational Antibacterial Drug Development

Multi-drug resistance in human bacterial pathogens has become a significant challenge for global healthcare this century, mainly due to the widespread misuse of antibiotics worldwide. As a result, millions of people have been affected by multi-drug-resistant bacterial infections. The antibiotic development pipelines cannot cope with the need to produce new antibiotics. Therefore, more productive antibiotic development methods must be invented. This paper presents an entirely rational approach for antibacterial drug discovery based on chimeric antisense oligonucleotide targeting (ASO) of the adenylate kinase mRNA in Staphylococcus aureus. The ASO is delivered into the bacteria via the cell-penetrating oligopeptide pVEC. The pVEC-ASO1 exhibits a bactericidal effect against Staphylococcus aureus, with a 50% minimal inhibitory concentration of 500 nM. The pVEC-ASO1 has a 98% survivability rate at the same concentration on cell lines. These findings strongly suggest that this chimeric ASO is a promising antibacterial drug candidate. Moreover, this is the fifth bacterial mRNA we have successfully targeted with pVEC-ASOs, providing further evidence for the efficiency of our approach. In contrast to the previous four targets, riboswitches residing in the 5′-untranslated region, we target the coding part of mRNA found in bacteria. That suggests that our approach may have much broader therapeutic applications.