AN EIF4G-RECRUITING APTAMER INCREASES THE FUNCTIONALITY OF IN VITRO TRANSCRIBED MRNA

Background: As a versatile and safe vector, in vitro transcribed messenger RNA (ivt mRNA) is currently being intensively evaluated as an active pharmaceutical ingredient. Its therapeutic uses encompass vaccination, cell reprogramming, genome engineering, gene complementation and the expression of protein drugs (e.g., growth factors or antibodies).  Objectives: The therapeutic efficacy of ivt mRNA correlates with the efficacy of its translation. Untranslated regions (UTRs) from stable mRNA, such as globin mRNA, and optimized 5’ cap structures have been used to improve the functionality of ivt mRNA. However, the recruitment of the eukaryotic initiation factor 4E (eIF4E) protein to the 5’ end of transfected ivt mRNA remains a ratelimiting parameter for translation.  Method: We added aptamer sequences that bind the eiF4G protein to the 5’ UTR of ivt mRNA. Results: One of the tested aptamer sequences produced a several fold increase in ivt mRNA expression (specifically, an increase of threefold to over tenfold depending on mRNA sequence and cell type).  Conclusion: This simple modification of the 5’ UTR of ivt mRNA may represent an efficacious and general method for improving the therapeutic index of all new mRNA-based therapeutic products.