Recombinant Ranpirnase enhances the expression of co-transfected mRNA by modulating cellular metabolic activity

As the worlds first approved prophylactic mRNA vaccine, the development of the Covid-19 mRNA vaccine marks a milestone in mRNA therapeutics. However, achieving efficient transgene expression in therapeutic applications such as protein replacement and cancer therapeutical vaccines remains challenging. This study explores the use of recombinant Ranpirnase, a small ribonuclease, as a novel expression-enhancing tool for mRNA-based therapeutics. In Balb/c mice, co-expression of Ranpirnase significantly increased transgene expression levels by 3-to 6-fold and prolonged expression duration by more than 85%, regardless of mRNA nucleoside modification status. Recombinant Ranpirnase induces a cytostatic state in host cells, stabilizing mRNA and protein transcripts, thereby enhancing transgene expression. Importantly, co-expression of Ranpirnase recombinants did not cause detectable cytotoxicity or alter the tissue distribution of transgene expression, ensuring safety and tolerability at higher translation levels. The compact size of the recombinant Ranpirnase gene allows for seamless fusion with the target gene or co-transfection with existing delivery technologies. Altogether, recombinant Ranpirnase shows promise as an expression-enhancing element in mRNA-based therapeutics, including veterinary applications.