基于脂筏学说定量检测脂质蛋白质相互作用新方法的研究

Lipid rafts are fluctuating nanoscale lipid assemblies which are rich in cholesterol, sphingolipids and certain proteins; these rafts are floating in a “sea” of low-melting phospholipids. Lipid rafts are thought to be responsible for several basic cellular processes (e.g., signal transduction and membrane protein trafficking) in a network of the membrane proteins and lipids coexisting bilayer. The interactions between membrane proteins and lipids are crucial for proper cellular homeostasis. Unfortunately, these nuanced interactions have proven to be extremely difficult to characterize using the current arsenal of biophysical techniques. Previously, we quantified the interactions between different kinds of phospholipids and cholesterol using our unique “Nearest-Neighbor Recognition” method, proposed the “Push-Pull” mechanism on lipid rafts formation. The goal of this program is to address lipid-protein interactions by developing a robust and powerful “Nearest Neighbor Recognition” methodology, which will allow one to probe the preference of the C99 polypeptide from the amyloid precursor protein, for a particular lipid over another as a nearest-neighbor, probe the push-pull forces of lipid rafts formation in a greater detail. Importantly, the data that are obtained will be quantitative thermodynamic values. This methodology will be generally applicable to a wide variety of membrane proteins or macromolecules. This program will provide more evidences on the lipid raft principle and give a deeper understanding of the lipid raft related cellular processes.

脂筏是富含胆固醇、高熔点脂质及特定膜蛋白的纳米微结构域，它包含于膜蛋白和脂质在双层膜环境中相互作用产生的网络中。脂筏学说认为，膜蛋白和脂质的相互作用在信号转导、物质的跨膜运输及病毒入侵等过程中起重要作用。但是由于当前生物物理技术难以准确定量表征蛋白质-脂质的相互作用，脂筏学说未被完全证实。申请人前期研究中通过最近邻识别的方法定量表征了不同类型磷脂和胆固醇之间的相互作用，提出了脂筏形成的Push-Pull机理。本项目拟在前期研究基础上，以淀粉样前体蛋白C99和不同脂质的相互作用为研究对象，通过开发新型最近邻识别方法探测膜蛋白对特定脂质的偏好，确证脂筏形成的Push-Pull机理并实现蛋白质-脂质的相互作用的直观定量测定。此方法能拓宽至其他脂质和蛋白质生物大分子之间相互作用的定量测定，具有广泛的应用价值。本项目为完善脂筏学说，解释基于脂筏学说的细胞生命现象及设计相关药物提供理论基础。

脂筏学说未被完全证实。本项目以淀粉样前体蛋白C99和不同脂质的相互作用为研究对象，通过开发新型最近邻识别方法探测膜蛋白对特定脂质的偏好，确证脂筏形成的Push-Pull机理并实现蛋白质-脂质的相互作用的直观定量测定。抗肿瘤药物普遍面临溶解性差、靶向性差、抗肿瘤机制单一等问题，肿瘤异常代谢构筑的乏氧、抗氧化、多药耐药和免疫抑制等环境会进一步限制抗肿瘤药物疗效。基于此，本项目设计并制备了一系列肿瘤微环境调控的靶向纳米药物，通过提高药物对肿瘤组织的靶向效率提升药物利用率，并通过调控肿瘤微环境赋予药物的抗肿瘤协同机制。本项目首先构建了具有细胞膜脂质靶向的纳米药物，并联合抑制线粒体氧化磷酸化和促进细胞铁死亡等过程，改善肿瘤乏氧和抗肿瘤拮抗机制，实现细胞膜靶向精准光动力学治疗。进一步的，通过调控药物分子间的非共价作用力，拓展出无载体自传递纳米药物和金属配位纳米药物递送创新体系，具有药物含量高、副作用小、制备简单等优点，联合药物共递送的性质和肿瘤药物拮抗的特点，筛选不同功能的药物分子构建自传递纳米药物，分别实现了改善肿瘤乏氧、逆转肿瘤免疫抑制、打破肿瘤细胞抗氧化等微环境调控策略，进而实现了肿瘤靶向光动力学治疗、化疗、免疫治疗等抗肿瘤协同机制，能有效的实现原发瘤、远端瘤和转移瘤的协同抑制。本项目已完成预定研究目标，为脂质蛋白质相互作用、肿瘤靶向策略、纳米药物的构建、肿瘤微环境调控方式及肿瘤协同治疗机制提供了新的思路和见解。在本项目资助下，本项目发表学术论文6篇，包括Chemical Engineering Journal、Journal of Controlled Release、Biomaterials Science、Chemical Communications等化学和材料领域具有一定影响力的国际学术期刊，均已明确标注本基金资助。

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