Delivery systems play a crucial role in RNA therapy. However, the current RNA delivery system involves complex preparation and transport processes, requiring RNA preassembly in vitro, transportation at low temperatures throughout, and possibly multiple injections for improved therapeutic efficacy. To address these challenges, we developed a simple and efficient RNA delivery system. This system only requires the injection of engineered bacteria, which serve as in vivo “cell factories” for continuous production of the target RNA. The RNA can self-assemble with engineered bacteria’s outer membrane vesicles (OMVs), facilitating in vivo RNA delivery. Experimental results demonstrated that this system allowed effective delivery with excellent stability and continuity for various types of RNA, including mRNA, miRNA, and siRNA. And the relative abundance of target RNA in the OMVs was 10⁴–10⁷ times higher than that in the mock group. We took the delivery of PD-L1 siRNA for tumor treatment as an example and found that this system could effectively downregulate the gene expression of PD-L1 by approximately twofold. Notably, a single injection of engineered bacteria achieved a significant tumor suppression of 49.37% in vivo. This research provides promising insights into the RNA delivery system for tumor therapy.

中文翻译：

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在肿瘤治疗中利用工程细菌作为体内“细胞工厂”，实现细胞内载有 RNA 的外膜囊泡自组装


递送系统在 RNA 治疗中起着至关重要的作用。然而，目前的 RNA 递送系统涉及复杂的制备和运输过程，需要在体外进行 RNA 预组装，在整个低温下运输，并可能进行多次注射以提高治疗效果。为了应对这些挑战，我们开发了一种简单高效的 RNA 递送系统。该系统只需要注射工程细菌，这些细菌作为体内“细胞工厂”，用于连续生产目标 RNA。RNA 可以与工程细菌的外膜囊泡 （OMV） 自组装，促进体内 RNA 递送。实验结果表明，该系统能够有效递送各种类型的 RNA，包括 mRNA、miRNA 和 siRNA，并具有出色的稳定性和连续性。OMV 中靶 RNA 的相对丰度是模拟组的 10^{4-10 7} 倍。我们以递送 PD-L1 siRNA 用于肿瘤治疗为例，发现该系统可以有效地将 PD-L1 的基因表达下调约两倍。值得注意的是，单次注射工程细菌在体内实现了 49.37% 的显着肿瘤抑制。这项研究为用于肿瘤治疗的 RNA 递送系统提供了有希望的见解。