The design of gene therapies with drug-regulatable expression of therapeutic payloads is of interest for diverse applications. We hypothesized that a regulated expression system based on alphavirus-derived self-amplifying RNAs (saRNAs), which encode 4 non-structural proteins (nsPs) that copy the RNA backbone to enable sustained expression, would have advantages in safety and simplicity of delivery. Here we designed saRNAs where payload expression is regulated by the FDA-approved drug trimethoprim (TMP), by fusing TMP-responsive degradation domains (DDs) to nsPs to regulate RNA self-amplification. Screening a library of nsP-DD fusions, we identified an optimal design with DDs fused to nsP2, nsP3, and the payload, achieving a high fold-change in expression level in response to TMP and low expression in the off state. In mice, this saRNA circuit enabled diverse dynamic expression patterns in response to oral TMP. Implementing this circuit for controlled expression of an HIV antigen, an escalating TMP regimen significantly enhanced germinal center responses critical for B cell affinity maturation. This drug- regulated RNA technology holds potential for vaccines, immunotherapies, and gene therapies.
Engineering gene expression dynamics via self-amplifying RNA with drug-responsive non-structural proteins
Parisa Yousefpour,Justin R Gregory,Kristen Si,Jan Lonzaric,Yingzhong Li,Junmin Wang,Kashif Qureshi,Amir Ledbetter,Ashley A. Lemnios,Jonathan Dye,Tanaka Remba,Rachel Yeung,Melissa Güereca,Linette Rodriguez,Yuebao Zhang,Shengwei Wu,Yizhou Dong,R. Weiss,Darrell J. Irvine
Published 2025 in bioRxiv
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- Publication year
2025
- Venue
bioRxiv
- Publication date
2025-06-08
- Fields of study
Biology, Medicine, Engineering
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Semantic Scholar, PubMed
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