New Preprint: in vitro circRNAs from Philipp Koch (21.5.2026)

🚨 Check out the 2nd preprint from our lab on how IRES-mediated translation of synthetic circRNAs is employed in cells and in cell-free translation extracts, a highly collaborative effort with Immagina Biotechnology S.r.l. & the labs of Anders Lund and CK Chen.

Biorxiv Preprint

Circular RNAs, naturally occurring and stable RNAs, are increasingly used as synthetic tools for sustained therapeutic protein translation by IRES-driven initiation. However, the functionality of different IRESes in synthetic circRNAs remains sparsely characterized.

We test IRES features in circRNAs:
• synthetic circRNA translation in cells and in cell-free extracts
• IRES identity (viral vs cellular) and translation activity in circRNAs
• immunogenicity of circRNAs dependent on purity and IRES identity
• engineering of IRES-mediated circRNA translation

We find:
• Systematic comparison identifies efficient viral and cellular IRESes for circRNA translation.
• Improved circRNA purification removes immune-stimulating contaminants affecting translation.
• Human cell-free system enables precise engineering of IRES-driven circRNA translation.

🎉 Huge congrats on this achievement to first author Philipp Koch in our lab, thank you to all authors from the Immagina, Lund, Chen and Leppek lab teams, and the funding sources that made this possible!