Poster abstracts
Poster number 156 submitted by Maddy Zamecnik
Incorporating common ASO modifications into mRNAs impacts translation speed
Maddy Zamecnik (University of Michigan, Department of Chemistry), Dan OReilly (University of Massachusetts Chan Medical School, RNA Therapeutics Institute), Anastasia Khvorova (University of Massachusetts Chan Medical School, RNA Therapeutics Institute), Kristin Koutmou (University of Michigan, Department of Chemistry)
Abstract:
RNA therapeutics require chemical modifications to their RNAs to extend their lifespans in the cell. Nucleobase modifications like N1-methylpseudouridine can increase the effectiveness of mRNA therapeutics, but a different suite of modifications has been developed for decades to solve a similar problem in other types of RNA therapeutics, including antisense oligonucleotides (ASOs). Specifically, modifications including 2’-O-methoxyethyl RNA (MOE), locked nucleic acids (LNA), and unlocked nucleic acids (UNA) have long been explored in ASOs for their abilities to increase binding affinities, decrease immunogenicity, and slow RNA degradation. However, these modifications have not been explored for their potential applicability to mRNA therapeutics. This lack of research is particularly surprising given that MOE is already being used in approved therapeutics, they are all compatible with existing ASO delivery techniques, and each has had a method of enzymatic synthesis already developed for it. Given this knowledge gap, I have employed an in vitro, reconstituted, E. coli translation system to assess how each of these modifications influences the kinetics of translation elongation when they are inserted into all 3 positions of a codon. Our findings indicate that the effects of the modifications on peptide bond formation are context dependent, varying depending on the position of the modification in the codon. While some modified codons produced only mild (2-fold) or nonsignificant changes in peptide bond formation relative to an unmodified codon, others stopped translation entirely. These results suggest that the suite of RNA modifications already developed for ASOs may provide a viable avenue to expand the chemical toolbox for mRNA therapeutics development.
Keywords: therapeutics, rna modifications, translation kinetics