Rational Design of Chimeric Antisense Oligonucleotides that Target FMN Riboswitch mRNAs and Inhibit the Growth of...

Area of Science:

• Microbiology
• Molecular Biology
• Drug Discovery

Background:

• Antimicrobial resistance (AMR) is a global health crisis, with methicillin-resistant Staphylococcus aureus (MRSA) being a major concern.
• Targeting essential bacterial pathways offers a strategy to combat drug-resistant pathogens.

Purpose of the Study:

• To design and evaluate chimeric antisense oligonucleotides (ASOs) targeting the flavin mononucleotide (FMN) riboswitch in MRSA.
• To assess the specificity and cytotoxicity of these novel ASOs.

Main Methods:

• Chimeric antisense oligonucleotides (ASOs) were designed to target the conserved FMN riboswitch.
• ASOs were chemically modified, conjugated to the pVEC cell-penetrating peptide, and tested for antibacterial activity against MRSA.
• Specificity was confirmed using Escherichia coli, and cytotoxicity was assessed in human A549 cells.

Main Results:

• The pVEC-ASO-3 conjugate demonstrated potent antibacterial activity against MRSA, with MIC50 and MIC90 values in the nanomolar range.
• No significant inhibition was observed in E. coli, indicating target specificity.
• High cell viability (95%) was observed in human A549 cells, suggesting low cytotoxicity.

Conclusions:

• Riboswitch-targeted ASOs represent a promising new class of antibacterial agents.
• These ASOs selectively inhibit MRSA growth with minimal toxicity, offering a potential solution against drug-resistant bacteria.