<i>In Vivo</i> Prime Editing by Lipid Nanoparticle Co-Delivery of Chemically Modified pegRNA and Prime Editor mRNA
Zexiang Chen, Karen Kelly, Haoyang Cheng, Xiaolong Dong, Adam K. Hedger, Li Li, Erik J. Sontheimer, Jonathan K. Watts
Abstract
Prime editing (PE) has gained significant attention as a next-generation gene editing technology, owing to its unique advantages. However, realizing its potential in vivo requires effective delivery strategies. While adeno-associated virus (AAV) has been employed for in vivo delivery of prime editors in research settings, it presents inherent limitations related to vector size, ongoing expression, and inability to re-dose patients. Conversely, lipid nanoparticles (LNPs) do not face these limitations and are emerging as a leading nonviral approach for the delivery of gene editors. In this study, we demonstrate successful co-delivery of chemically modified pegRNA and prime editor mRNA using LNPs for in vivo PE. We investigate the impact of pegRNA chemical modifications on editing efficiency and explore different re-dosing regimens. In a daily-repeat dose regimen, we saw striking liver toxicity and no increase in editing; by contrast, weekly repeat dosing was well tolerated and enabled 1.8-fold increase in editing efficacy. Furthermore, in the NOD scid gamma immunodeficient mouse model, the efficacy of LNP-delivered PE was enhanced by 2.8-fold. In addition, the nature of the ionizable lipids and phospholipids strongly influenced PE efficiency in vivo . Overall, these findings will greatly contribute to the future development of LNPs as a robust platform for delivering prime editors in vivo , fostering progress in PE research and therapeutic applications.