基于“免疫靶向-逐级释药-多靶响应”的大黄-栀子组分共载纳米治疗溃疡性结肠炎机制研究

"Rhei Radix et Rhizoma and Gardeniae Fructus" is a classic Chinese herb pair, with the function of clearing heat and promoting dampness. It is often used in treating "dampness-heat accumulated intestine" type of ulcerative colitis (UC). Applicant's previous studies have found that Rhein and Geniposide, two active compounds from Rhei Radix et Rhizoma and Gardeniae Fructus, can significantly relieve the UC symptoms in UC mice model, which might be the effects of immune suppression and intestinal flora regulation of Rhein and Geniposide respectively. However, how to co-deliver these two components to colon directly and efficiently is a big challenge in UC treatment. Based on the previous study about oral human serum albumin (HSA) targeted nanoparticles which was completed by applicant during the PhD study period, a hypothesis is proposed that Rhein and Geniposide layer-encapsulated by HSA nanoparticles with immune cells-targeted function, will show the synergistic effects of components on UC treatment via targeting immune cells and inducing multi-targets response...Based on the characteristics of high biocompatibility and drug loading capacity for HSA, we will design a novel drug co-loading system by physically internal loading of Rhein and chemically crosslinking of Geniposide, which has two obvious advantages of layer-encapsulating drugs and enhancement of carrier stability. Based on pathogenesis of UC, OX40 monoclonal antibody will be further modified on the surface of nanoparticles so as to recognize T lymphocytes around UC lesions. Ultimately, a co-loading components oral delivery system with the function of immune cells-targeted, gradual release and multiple targets response will be constructed. In addition, we will also clarify the mechanism of combination of Rhein and Geniposide in treating UC via immunosuppression of mTOR pathway and regulation of intestinal SCFAs-producing flora though this colon-targeted co-delivery design, which will provide valuable reference to co-delivery herb components research.

“大黄-栀子”为中医“清热利湿”经典药对，常用于治疗“湿热蕴肠”型溃疡性结肠炎（UC）。前期研究发现该药对有效组分大黄酸-栀子苷可能通过免疫抑制和肠道菌群调控，显著改善小鼠UC症状。但如何实现该组分均衡高效靶部位共递送，为其治疗UC瓶颈。基于申请人博士期间人血清白蛋白（HSA）口服靶向纳米研究，提出假说：采用免疫细胞主动靶向的HSA纳米对大黄酸-栀子苷进行共载，实现免疫靶向和多靶点协同抗UC。.本项目根据HSA高生物相容性和载药性能，进行“大黄酸物理包载-栀子苷化学交联”创新性载药设计，以实现药物多层次包载和载体稳定性增强双重优势；基于UC病灶特征，将OX40单抗修饰于纳米表面以主动识别T细胞；最终构建大黄酸-栀子苷“免疫靶向-逐级释药-多靶响应”共载口服纳米体系，并从mTOR通路免疫抑制和SCFAs分泌菌群调控角度，阐明大黄酸-栀子苷配伍治疗UC机制，为组分中药共传递抗UC提供新思路。

溃疡性结肠炎（UC）是临床难治病，其病机复杂，临床一线药物干预机制单一，且疗效局限。中医学以“清热利湿”法干预“湿热蕴肠”型 UC，其中“清热利湿”药大黄、栀子临床应用疗效确切，亟待开发。本项目通过挖掘大黄、栀子有效成分（组分）对UC治疗的潜质，瞄准该类成分存在的难以抵达UC病灶、生物利用度低等制剂学难题，引入“食药结合”制剂学口服靶向微纳米递药策略，形成了三方面的研究成果：其一、筛选中药大黄五种蒽醌类成分在UC的治疗作用及各自作用特色，筛选出大黄酸和大黄素；其二、建立项目计划中重点提及的基于栀子苷元作为天然交联剂，交联HSA形成的口服纳米递药系统，装载中药有效成分大黄酸和姜黄素等，用于UC的治疗；其三、拓展设计形成了五种口服微纳米递药系统，用于中药有效成分口服递送治疗UC：（1）采用栀子苷元作为天然交联剂，交联HSA形成的口服纳米递药系统，并佐以单宁酸进行胃肠道保护与肠道黏膜黏附，用以口服递送大黄酸或姜黄素治疗UC；（2）采用“静电吸附-真空挤压-静电分布-水化重排”微纳米制备技术，制备了基于酵母细胞壁（YPs）载大黄酸血清蛋白纳米多层体系，并结合免疫细胞靶向策略治疗UC；（3）采用YPs包载技术，包载载大黄素乳铁蛋白纳米，构成大球包小球的复合纳米体系，并强调不同层微纳米设计对免疫细胞的靶向与摄取特色，用于UC的口服治疗；（4）采用pH/ROS双敏感复合多糖对大黄酸进行口服递送，并强调中药有效成分多途径调控UC优势，完成对载大黄酸复合多糖口服纳米抗炎、抗氧化、黏膜修复和菌群调控作用探讨；（5）采用超分子纳米构建技术，制备大黄酸超分子纳米体系，并佐以复合多糖天然载药系统，形成具有免疫细胞靶向和ROS敏感的口服纳米递药系统，用于治疗UC。本研究基于项目的基本任务，实现了多种中药新型口服微纳米递药系统治疗UC，并发表多篇高水平SCI论文，培养多名人才，并基于此开展了下一个面上项目的研究。