RNA stability enhancers for durable base-modified mRNA therapeutics.

Area of Science:

• Molecular Biology
• Biotechnology
• Vaccinology

Background:

• Limited in vivo stability of messenger RNA (mRNA) hinders vaccine and therapeutic development.
• Alternative RNA formats like circular RNA (circRNA) and self-amplifying RNA (saRNA) offer durability but face challenges in translation, modification compatibility, and manufacturing.
• Need for enhanced linear mRNA platforms that are stable, translatable, and manufacturable.

Purpose of the Study:

• To identify elements that enhance mRNA stability and translation.
• To overcome limitations associated with current RNA modalities.
• To develop robust linear mRNA platforms for therapeutic and vaccine applications.

Main Methods:

• Screened 196,277 viral sequences to identify RNA stability and translation enhancers.
• Investigated the mechanism of action, including poly(A) tail extension via TENT4 recruitment.
• Assessed compatibility with N¹-methylpseudouridine modification and evaluated performance across various cell types, delivery methods, and coding sequences.

Main Results:

• Identified eleven viral elements that significantly enhance mRNA stability and translation.
• Discovered that these elements recruit TENT4 to extend the poly(A) tail, preventing deadenylation.
• An element named A7 demonstrated superior performance, making linear mRNA as stable as circRNA with higher translation efficiency and sustained protein expression over 2 weeks in vivo.

Conclusions:

• Novel RNA stability enhancers enable robust linear mRNA platforms.
• These platforms offer high and durable expression, low immunogenicity, and simplified manufacturing.
• The findings pave the way for advanced mRNA-based vaccines and therapeutics.