Highly efficient cellular expression of circular mRNA enables prolonged protein expression

Area of Science:

• Molecular Biology
• Biotechnology
• Drug Delivery Systems

Background:

• Messenger RNA (mRNA) therapeutics face challenges with short protein expression duration due to mRNA's limited half-life.
• While in vitro circular mRNA production enhances stability, in-cell synthesis in mammalian cells remains difficult, hindering therapeutic applications.
• Existing mRNA delivery methods often struggle to achieve prolonged protein expression.

Approach:

• Adapted the Tornado (Twister-optimized RNA for durable overexpression) system for in-cell synthesis of circular mRNAs.
• Identified specific promoters and internal ribosomal entry sites (IRES) to maximize protein expression from circular mRNAs within cells.
• Developed a method to package these in-cell synthesized circular mRNAs into virus-like particles (VLPs).

Key Points:

• Successfully achieved in-cell synthesis of circular mRNAs using an adapted Tornado system.
• Optimized promoter and IRES elements for high-level protein expression from circular mRNAs in mammalian cells.
• Demonstrated that circular mRNAs packaged into VLPs enable significantly prolonged protein expression.

Conclusions:

• Presents a novel platform for the intracellular synthesis of circular mRNAs.
• Highlights the potential of circular mRNAs to enhance the efficacy of VLP-based mRNA delivery systems.
• Advances the development of more stable and effective mRNA therapeutics and cell-derived therapies.