Developing an Enhanced Chimeric Permuted Intron-exon System for Circular RNA Therapeutics

Overview

Journal Theranostics

Date 2024 Sep 30

PMID 39346546

Authors

Lei Wang

Chunbo Dong

Weibing Zhang

Xu Ma

Wei Rou

Kai Yang

Tong Cui

Shaolong Qi

Lijun Yang

Jun Xie

Guocan Yu

Lianqing Wang

Xiaoyuan Chen

Zhida Liu

Affiliations

Soon will be listed here.

Abstract

: Circular RNA (circRNA) therapeutics hold great promise as an iteration strategy in messenger RNA (mRNA) therapeutics due to their inherent stability and durable protein translation capability. Nevertheless, the efficiency of RNA circularization remains a significant constraint, particularly in establishing large-scale manufacturing processes for producing highly purified circRNAs. Hence, it is imperative to develop a universal and more efficient RNA circularization system when considering synthetic circRNAs as therapeutic agents with prospective clinical applications. We initially developed a chimeric RNA circularization system based on the original permuted intron-exon (PIE) and subsequently established a high-performance liquid chromatography (HPLC) method to obtain highly purified circRNAs. We then evaluated their translational ability and immunogenicity. The circRNAs expressing human papillomavirus (HPV) E7 peptide (43-62aa) and dimerized receptor binding domain (dRBD) from SARS-CoV-2 were encapsulated within lipid nanoparticles (LNPs) as vaccines, followed by an assessment of the efficacy through determination of antigen-specific T and B cell responses, respectively. We have successfully developed a universal chimeric permuted intron-exon system (CPIE) through engineering of group I self-splicing introns derived from Anabaena pre-tRNA or T4 phage thymidylate (Td) synthase gene. Within CPIE, we have effectively enhanced RNA circularization efficiency. By utilizing size exclusion chromatography, circRNAs were effectively separated, which exhibit low immunogenicity and sustained potent protein expression property. data demonstrate that the constructed circRNA vaccines can elicit robust immune activation (B cell and/or T cell responses) against tumor or SARS-CoV-2 and its variants in mouse models. Overall, we provide an efficient and universal system to synthesize circRNA , which has extensive application prospect for circRNA therapeutics.

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