In vivo self-assembled small RNAs as a new generation of RNAi therapeutics

Zheng Fu,Uzair Ur-Rehman,Chenyu Zhang ,Xiang Zhang,Jing Li,Hongyuan Guo,Han Li ,Jinrong Wu,Wei Cheng,Yangyang Ye,Yan Kong,Xiuting Hu,Chao Yan,Ke Zen,Mengchao Yu,Yuanyuan Su,Hongwei Liang,Xu Guo,Xinyan Zhou,Lu Sheng ,Yayun Gu,Dianqing Wu,Xi Chen

doi:10.1038/s41422-021-00491-z

Abstract

RNAi therapy has undergone two stages of development, direct injection of synthetic siRNAs and delivery with artificial vehicles or conjugated ligands; both have not solved the problem of efficient in vivo siRNA delivery. Here, we present a proof-of-principle strategy that reprogrammes host liver with genetic circuits to direct the synthesis and self-assembly of siRNAs into secretory exosomes and facilitate the in vivo delivery of siRNAs through circulating exosomes. By combination of different genetic circuit modules, in vivo assembled siRNAs are systematically distributed to multiple tissues or targeted to specific tissues (e.g., brain), inducing potent target gene silencing in these tissues. The therapeutic value of our strategy is demonstrated by programmed silencing of critical targets associated with various diseases, including EGFR/KRAS in lung cancer, EGFR/TNC in glioblastoma and PTP1B in obesity. Overall, our strategy represents a next generation RNAi therapeutics, which makes RNAi therapy feasible.

Highlights

RNA interference (RNAi) offers an opportunity to target mRNAs and modulate the expression of corresponding proteins before their biogenesis, and has been proposed as a promising therapeutic tool to manipulate the expression of disease-related genes, especially the genes that are considered undruggable using traditional approaches.[1,2,3] RNAi therapy has encountered many problems and falls way behind expectation during clinical translation
Because synthetic biology enables the design of composable, controllable and multifunctional genetic circuits to reprogramme cells and even allow cells to self-assemble into new, user-defined tissues,[17,18] we proposed an intriguing idea that host tissues may be engineered and converted to live biogenerators of RNAi therapeutics through the integration of the naturally existing circulating exosome system with artificial genetic circuits
Numerous small molecules and antibodies have been developed to target these proteins, the applicability of current targeted therapies is still limited to a small fraction (< 1%) of the human proteome.[44] small interfering RNAs (siRNAs) offer an opportunity to target mRNAs and modulate the expression of corresponding proteins before their biogenesis,[3,45] and have greatly enlarged the proportion of human proteins that can be therapeutically manipulated.[46]

Summary

Introduction

RNA interference (RNAi) offers an opportunity to target mRNAs and modulate the expression of corresponding proteins before their biogenesis, and has been proposed as a promising therapeutic tool to manipulate the expression of disease-related genes, especially the genes that are considered undruggable using traditional approaches.[1,2,3] RNAi therapy has encountered many problems and falls way behind expectation during clinical translation. In the first stage, naked small interfering RNAs (siRNAs) or chemically modified stable siRNAs were synthesized and directly injected for systematic delivery; yet these siRNAs cannot effectively pass biological barriers and reach target genes.[3] In the second stage, various delivery vehicles (e.g., lipid nanoparticles, cationic polymers and viruses) or conjugated ligands Acetylgalactosamine (GalNAc)) were invented to increase the efficiency of siRNA delivery in vivo.[4,5] The recent FDA approval of the first (Patisiran, siRNA is formulated as a lipid complex for the delivery to hepatocytes6) and second (Givosiran, siRNA is conjugated to a GalNAc ligand that enables asialoglycoprotein receptors-mediated targeted delivery to hepatocytes7) siRNA drugs marked the beginning of the era of RNAi therapeutics

Methods

Results

Conclusion