Peptide nucleic acid-mediated circularization of target RNA as tool to inhibit translation

Antisense oligonucleotides (ASOs) are short, synthetic sequences designed to specifically target RNA target molecules to modulate their translation and protein expression. To enhance their stability, chemically modified ASOs have been developed. Over the decades, peptide nucleic acids (PNAs) have emerged as powerful tools in molecular biology, proving their ability in gene knockdown, as well as therapeutic or diagnostic applications. In this study, we sought to explore the potential of PNAs to inhibit RNA translation through a novel mechanism of action. To enhance translation inhibition, we designed a new class of PNAs able to mediate target RNA circularization. These PNAs bind the 5' end of the RNA, interacting with CAP and 5'UTR structures, while simultaneously binding to the poly-A tail at the opposite end of the same RNA molecule. Our findings suggest target RNA circularization and inhibition of protein translation across multiple models. We established a dose-dependent effect of the circularizing PNAs on target RNA translation. Overall, our results reveal that this dual-targeting approach strongly inhibits RNA translation compared to binding solely to the 5'UTR, paving the way to the potential development and therapeutic application of this novel class of ASO PNAs.