Engineering Antisense Oligonucleotides as Antibacterial Agents That Target FMN Riboswitches and Inhibit the Growth of Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli

In the past several decades, antibiotic drug resistance has emerged as a significant challenge in modernmedicine due to the rise of many bacterial pathogenic strainsresistant to all known antibiotics. At the same time, riboswitcheshave emerged as novel targets for antibacterial drug discovery.Here for thefirst time, we describe the design and applications ofantisense oligonucleotides as antibacterial agents that target ariboswitch. The antisense oligonucleotides are covalently coupledwith two different cell-penetrating peptides, penetrating Gram-positive and Gram-negative bacterial cells. We specifically targetFlavin MonoNucleotide (FMN) riboswitches inStaphylococcus aureus,Listeria monocytogenes, andEscherichia colithat control bothsynthesis and import of FMN precursors. We have established an average antibiotic dosage by antisense oligonucleotides that inhibit80% of bacterial growth at 700 nM (4.5 mu g/mL). Furthermore, the antisense oligonucleotides do not exhibit toxicity in human celllines at this concentration. The results demonstrate that riboswitches are suitable targets in antisense technology for antibacterial drug development