内耳双靶向智能DNA纳米结构构建及递药机制研究

双重屏障限制和靶向性缺失是内耳疾病精准药物治疗失败主要原因。智能DNA纳米结构因结构可定制且易靶向修饰，有望突破双屏障限制并实现精准递药。本项目构建双肽（A666和SS31）修饰DNA纳米结构系统（AS-DDS），以期实现特异性内耳外毛细胞线粒体亚细胞结构药物定位输送。通过构建不同尺寸和立体结构DNA载体以获得高双屏障渗透性。通过A666-Prestin介导内吞作用进入外毛细胞，避开对其他非病变细胞损伤；同时，SS31可识别线粒体，实现药物亚细胞结构定位输送。以外毛细胞线粒体凋亡为主要病理特征的顺铂耳毒性小鼠为疾病模型，探讨双肽修饰载地塞米松（DEX）DNA纳米结构（AS-DEX-DDS）拮抗顺铂耳毒性的作用及机制。本项目首次探讨双靶向智能DNA纳米结构用于内耳外毛细胞线粒体靶向递送药物的可行性；同时，明确双靶向载体系统AS-DEX-DDS“协同”、“双重”抗顺铂耳毒性作用分子机制。

Dual barrier and lack of targeting are the major obstacle to precise drug treatment for inner ear diseases. Intelligent DNA nanostructures characterize with customizable structure and easy targeting modification is a promising strategy to break through dual barriers and precisely deliver drugs. Here, we developed a novel dipeptide (A666 and SS31) modified DNA nanostructure system (AS-DDS), aiming to achieve specific delivery of drugs to mitochondrial subcellular structure in outer hair cells. DNA vectors with different sizes and stereostructures were constructed by computer-aided data modeling to obtain high circular round window membrane permeability. AS-DDS enters outer hair cells through A666-Prestin mediated endocytosis to avoid damage to other non-pathological cells. Meanwhile, SS31 recognizes mitochondria and realizes subcellular structure localization and delivery of drugs. Ototoxicity of cisplatin is mainly caused by mitochondrial apoptosis of outer hair cells, which is used as a disease model to investigate the effect and mechanism of dipeptide modified dexamethasone (DEX) DNA nanostructure (AS-DEX-DDS) in antagonizing ototoxicity of cisplatin. In addition, the "synergistic" and "dual" antagonistic effects against cisplatin ototoxicity was achieved by inhibits ROS inhibition of SS31 polypeptide recognized mitochondria and high antioxidant activity of DEX. The present research is to explore the feasibility of using dual-targeting smart DNA nanostructures for targeted delivery of drugs to mitochondria of inner and outer ear hair cells, and to clarify the molecular mechanism of anti-cisplatin ototoxicity by dual-targeting carrier system AS-DEX-DDS. This project will provide innovative theoretical ideas for the construction of drug delivery vector system and strategy for inner ear, as well as the development of basic research and clinical application of prevention and treatment of cisplatin-induced hearing loss.