可促进药物经肠道细胞摄取和出胞的口服纳米递药系统的研究

Active targeting nanoparticles (NPs) can enhance the affinity with apical membrane of intestinal epithelium via specific ligand-receptor interaction, which increases the cellular uptake. However, the transport from basal membrane into the blood circulation is still limited. Two factors may induce this phenomenon: (i) the lysosomal degradation and (ii) the bidirectional exocytosis that leads to exocytosis from apical side. Thereby, it remains the bottle-neck for orally delivered nanovehicles to increase the basolateral exocytosis. In this study, inspired by transport pathways of lipids, we anchored analogues of cholesterol (25-hydroxycholesterol, 25-HC) and lysosomal escape regent histidine on traditional mucus-penetrating NPs. 25-HC could promote the endocytosis of NPs by interacting with receptors (Niemann-Pick C1 Like 1，NPC1L1) on the apical membrane. Meanwhile, by regulating the expression of ATP-binding cassette transporter-1 (ABCA1) on the basal side, they could boost the basolateral exocytosis of drugs. Additionally, histidine would facilitate the escape from endo/lysosomes, regulating the intracellular trafficking of NPs. In this research, the preparation and characterization of NPs will be performed. The stability and mucus-permeability will be evaluated. Next, the cellular transportation behaviors, including uptake, intracellular trafficking, exocytosis and the underlying mechanisms, will be systemically studied. Finally, the in vivo pharmacological and pharmacokinetic studies will be performed on diabetic rats. Safety issues will also be evaluated on cell models and animals. Therefore, this study may provide new insights into the problem of “easy entry, hard transcytosis” of orally delivered nanovehicles.

主动靶向纳米递药系统可通过配体-受体作用，增加纳米粒与肠上皮细胞顶侧膜亲和力，进而提高药物摄取。但由于①溶酶体的降解作用；②纳米粒出胞的“双向性”，即向顶侧膜大量外排，导致由基底侧转运入血的药物量受到极大限制。因此，如何增加药物的基底侧出胞成为口服递药的瓶颈问题之一。本课题拟借鉴脂质的胞内转运途径，在传统穿粘液纳米粒表面同时引入小分子胆固醇类似物配体（25-HC）和溶酶体逃逸剂组氨酸。25-HC与肠上皮细胞顶侧NPC1L1受体具有较好的亲和力，同时，可有效调控基底侧ABCA1受体的表达，进而促进药物入胞和基底侧出胞。组氨酸则可帮助实现内涵体/溶酶体逃逸，从而进一步调控胞内转运。本课题将系统研究该纳米粒的构建、稳定性以及穿粘液能力；其在肠上皮细胞摄取、胞内转运、出胞及作用机理，糖尿病动物体内药代动力学、药效学及初步安全性。为口服纳米递药系统克服“入胞容易出胞难”的瓶颈问题提供新的思路和方法。

针对主动靶向纳米粒口服递药存在“出胞难”的瓶颈问题，本课题利用胆固醇的胞内转运途径，通过调控上皮细胞顶侧和基底侧不同受体的表达，构建了可促进药物摄取和基底侧出胞的主动靶向口服纳米递药系统。研究结果表明，该纳米粒在胃肠道中保持一定的稳定性，在表面亲水PEG作用下，能够快速穿过肠道黏液，到达上皮细胞表面，进而利用胆固醇类似物25-HC与肠上皮细胞顶侧膜表达的PC1L1受体相互作用，增加药物的摄取。进入细胞后，内涵体-溶酶体逃逸剂INF-7肽介导纳米粒从内涵体/溶酶体中逃逸，25-HC 刺激基底侧ABCA1受体表达增加，从而进一步介导含有磷脂和胆固醇类似物的纳米粒的外排。以通讯作者在国际主流刊物Bioactive Materials, Acta Pharm Sin B，J. Control. Release，Biomaterials等本领域权威杂志发表SCI文章10篇，授权中国发明专利3项，申请2项。课题负责人获得长江学者特聘教授，以第一完成人和第一完成单位申请的“多肽蛋白类药物口服高效递释系统基础研究”获2019年教育部自然科学一等奖，国家科学技术进步二等奖（排名第6）。在国内外学术会议进行报告交流8次，承担科技部国际合作项目1项。参加编写研究生用书《新药研究与评价概论》和本科生教材《药剂学》。培养毕业博士研究生7名，硕士研究生16名。为口服纳米递药系统克服“出胞难”的瓶颈问题提供新的解决策略与数据支持。