Synthesis, Characterization, and Function of an RNA-Based Transfection Reagent

Area of Science:

• Oligonucleotide chemistry and delivery
• RNA therapeutics
• Gene therapy applications

Background:

• Phosphorodiamidate morpholino oligonucleotides (PMOs) are effective antisense agents but require efficient delivery systems.
• Alternative splicing modulation is a promising strategy for treating genetic diseases.

Purpose of the Study:

• To develop and evaluate a novel synthetic RNA element for enhanced PMO delivery.
• To demonstrate the efficacy of this delivery system in restoring protein function in cellular and animal models.

Main Methods:

• Solid-phase synthesis of a synthetic 8-mer, amphipathic, trans-acting poly-2 eal-O-methyluridylic thiophosphate triester RNA element (2 eal-OMeUtaPS).
• Transfection of HeLa pLuc 705 cells and mdx mouse muscle cells with PMO sequences mediated by 2 eal-OMeUtaPS.
• Assessment of gene expression and splicing using flow cytometry, luciferase assays, and agarose gel electrophoresis.

Main Results:

• 2 eal-OMeUtaPS efficiently mediated the delivery of uncharged polyA-tailed PMO sequences in HeLa cells.
• Restoration of functional luciferase was observed due to alternative splicing induction.
• Effective delivery of antisense PMO sequences in mdx mouse muscle cells led to the production of functional dystrophin by excising the mutated exon.

Conclusions:

• The synthetic 2 eal-OMeUtaPS RNA element is a potent and efficient tool for delivering antisense PMO sequences.
• This delivery system shows promise for therapeutic applications in genetic disorders, including muscular dystrophy, by restoring protein function through alternative splicing modulation.