Enhanced Intracellular Stability and Translation Efficiency of mRNA Drugs by a 2‐arm mRNA Platform

ABSTRACT The poly(A) tail deadenylation and transient protein expression of messenger RNA (mRNA) extremely hinder its therapeutic potential in genetic diseases, from which it follows that improving RNA stability and translation efficiency has emerged as a critical priority. In this study, we construct a 2‐arm mRNA via a streamlined modular assembly approach, characterized by a unique topology formed through the dimerization of two mRNA 3’ poly(A) tails. This distinctive architecture exhibits the capacity for efficiently recruiting poly(A)‐binding proteins (PABPs) to activate the eIF3‐eIF4F complex and promote highly efficient cap‐dependent translation, markedly improving 3’ tail stability and resistance to nuclease degradation, with an intracellular half‐life of up to 65 h. Furthermore, the 2‐arm mRNA sustains higher‐level protein expression for over two weeks in protein replacement therapy of hemophilic mice compared to linear mRNA. In conclusion, this work presents a novel 2‐arm mRNA platform that substantially enhances the translation capacity of mRNA, broadening its potential applications in mRNA‐based therapeutics, particularly for the treatment of genetic disorders.