Oligonucleotide drugs have been used widely as therapeutic agents for gene therapy, while their instability in biological media and inefficiency for intracellular delivery remain major hurdles for practical in vivo applications. Herein, we report a circular Y-shaped aptamer–DNAzyme conjugate (cYAD) for highly efficient in vivo gene silencing via RNA cleavage, which can been employed in various disease treatments, including cancer, inflammation, as well as viral infections. Systematic studies revealed that cyclization of the DNA structure could improve the stability of oligonucleotide drugs in vivo. Besides, the bivalent aptamer motifs provided a specific and enhanced tumor cell targeting ability for accumulation and retention of the oligonucleotide drugs at the tumor site. As a proof of concept, a widely applicable Na+ -dependent fluorescent sensor, NaA43 DNAzyme, was used to inhibit MET gene expression in mice tumor model tissues, which exhibited highly efficient gene silencing performance in vivo, which confirmed our findings with cYAD. This strategy provides a novel approach for the construction of oligonucleotide drugs for practical therapeutic applications.

中文翻译：

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Y形圆形适体-DNAzyme结合高效体内基因沉默。

寡核苷酸药物已被广泛用作基因疗法的治疗剂，而它们在生物介质中的不稳定性和细胞内递送的效率低下仍然是实际体内应用的主要障碍。在本文中，我们报道了一种环状Y形适体-DNAzyme偶联物（cYAD），可通过RNA切割实现高效的体内基因沉默，可用于多种疾病的治疗，包括癌症，炎症和病毒感染。系统研究表明，DNA结构的环化可以提高寡核苷酸药物在体内的稳定性。此外，二价适体基序提供了特异性和增强的肿瘤细胞靶向能力，用于寡核苷酸药物在肿瘤部位的积累和保留。作为概念证明，广泛应用的依赖Na +的荧光传感器NaA43 DNAzyme被用于抑制小鼠肿瘤模型组织中MET基因的表达，该基因在体内表现出高效的基因沉默性能，这证实了我们在cYAD中的发现。该策略为构建用于实际治疗应用的寡核苷酸药物提供了一种新颖的方法。