Flavin conjugates for delivery of peptide nucleic acids

Area of Science:

• Molecular Biology
• Biochemistry
• Drug Delivery

Background:

• Oligonucleotides and their analogues, like peptide nucleic acids (PNAs), are tools for controlling gene expression.
• Inefficient cellular uptake and localization hinder the biological applications of PNAs.
• Novel strategies are needed to improve PNA delivery and efficacy.

Purpose of the Study:

• To investigate the potential of conjugating PNAs to flavin for enhanced cellular internalization and delivery.
• To evaluate the antisense activity of flavin-PNAs and their ability to escape endosomes.
• To explore the use of the isoalloxazine moiety as a carrier for oligonucleotide analogues.

Main Methods:

• Conjugation of PNAs to flavin to create flavin-PNAs.
• Assessment of cellular uptake via endocytic pathways.
• Evaluation of antisense activity in the sub-micromolar range.
• Investigation of endosomal escape mechanisms using chloroquine and light irradiation (with rhodamine-conjugated flavin-PNAs).

Main Results:

• Flavin conjugation enabled efficient PNA internalization into cells through endocytosis.
• Flavin-PNAs demonstrated significant antisense activity.
• Endosomal release into the cytoplasm and nucleus was enhanced by chloroquine and light irradiation.
• Rhodamine conjugation to flavin-PNA acted as a photosensitizer, aiding endosomal escape upon irradiation.

Conclusions:

• The isoalloxazine moiety effectively serves as a carrier for PNA internalization and functional delivery to the cytoplasm/nucleus.
• Flavin-PNAs represent a promising strategy for improving the delivery and efficacy of antisense agents.
• This approach could guide the future design of PNAs and other oligonucleotide analogues for gene expression control.