Design and Evaluation Novel Gene-Specific, Cell-Permeable Antisense Peptide Nucleic Acids to Prevent Staphylococcus Aureus Biofilm Formation

Abstract

Staphylococcus aureus, a Gram-positive bacterium, is a leading cause of various biofilm-associated infections in humans and animals, posing significant economic and healthcare challenges. Biofilms exhibit heightened resistance to antimicrobial agents as well as to immune-mediated clearance, thus persisting for long periods of time. Hence, novel therapeutic approaches are needed to eradicate S. aureus biofilms. Peptide nucleic acids (PNAs), synthetic DNA analogs with a peptide backbone instead of sugar backbone, offer a promising approach. In this study, we designed, synthesized and tested the efficacy of several synthetic antisense PNAs coupled with cell-penetrating peptides (CPPs), targeting essential and biofilm related S. aureus genes to inhibit staphylococcal biofilm growth using standard microtiter plate and tygon catheter biofilm assays. P-PNAs targeting the genes for intercellular adhesion locus, ica, cell wall/membrane/envelope biogenesis, fmhb, accessory regulator, sarA, sensor histidine kinase, saeS, repressor of toxins, rot, response regulator, yycF and histidine kinase, yycG genes were tested. Two scrambled PNAs and CPP alone were used as controls. Only one P-PNA, targeting sarA, showed the strongest biofilm inhibitory activity (up to 40 %) at a concentration of 50 μM or higher. This novel P-PNA could be a useful adjunct for the treatment S. aureus biofilm infections.