PROMOTERS AND INHIBITORS OF MEMBRANE FUSION

该计划的长期目标是发明促进或抑制生物膜融合的新材料。这项工作将给健康和健康科学带来实际和智力上的好处。从实用的角度来看，新的融合催化剂的开发将是杂交瘤研究、基因治疗和药物输送领域的一项受欢迎的技术进步；而融合抑制剂可能作为一系列疾病领域的新型治疗药物，特别是机会性感染。将会有大量的智力贡献，因为促进剂和抑制剂的设计是为了在分子水平上测试我们目前对膜融合的理解。大多数早期工作将使用模型脂质体系统。这是因为生物膜是复杂的、非均相的基质，很难描述控制分子的因素。然而，有很好的证据表明，脂质体通过类似的机制融合，从模型研究中获得的知识可以用来解释融合蛋白是如何工作的。此外，对脂质体融合的详细了解本身也是一个临床有用的目标，因为脂质体被用作药物输送载体。目前，茎假说是膜融合最普遍、最普遍的机制。然而，由于瞬时融合中间体很难观察和表征，因此很难证明这一机制。对茎机制的仔细研究表明，具有特定拓扑和极性的分子应该能够稳定或不稳定假定的融合中间体，从而促进或抑制融合。这一应用的具体目的是：1.通过评估一系列构象受限的极性脂类的融合抑制能力来检验最近假想的、扩展的膜融合构象机制。2.制备和评价合理设计的促进茎融合机制的融合促进剂。将探索两种类型的融合促进剂，(I)填充和稳定茎间隙空洞的疏水十六烷树枝，以及(Ii)稳定茎融合中间体高度弯曲表面的球形离子树枝大分子。有效的启动子将被视为秸秆机制的支持证据，而负面结果将需要对该模型进行重新评估。3.制备了一系列树状大分子-类固醇和树状大分子-脂质体的结合物，并对其在基因治疗和药物释放方面的潜在应用进行了评价。4.利用积累的数据制定了改进的生物膜融合的分子机理。

The long-term goal of the program is to invent new materials that promote or inhibit the fusion of biological membranes. The work will bring practical as well as intellectual benefits to health and health science. From a practical perspective, the development of new fusion catalysts would be a welcome technological advance in the fields of hybridoma research, gene therapy and drug delivery; whereas, fusion inhibitors may be useful as novel therapeutic agents for a range of disease areas, especially opportunistic infection. There will be substantial intellectual contributions as the promoters and inhibitors are designed to test our current understanding of membrane fusion at the molecular level. Most of the early work will use model liposome systems. This is because biological membranes are complicated, heterogeneous matrices, and it is difficult to delineate the controlling molecular factors. However, there is good evidence that liposomes fuse by a similar mechanism, and that the knowledge gained form the model studies can be used to explain how fusion proteins work. Furthermore, a detailed understanding of liposome fusion is itself a clinically useful goal because liposomes are used as drug delivery vehicles. Currently, the stalk hypothesis is the most accepted, general mechanism for membrane fusion. However, it is hard to prove this mechanism because the transient fusion intermediates are difficult to observe and characterize. A close examination of the stalk mechanism suggests that molecules with specific topologies and polarities should be able to stabilize or destabilize the putative fusion intermediates and thus promote or inhibit fusion. The specific aims of this application are: 1. Test the recently hypothesized, extended conformation mechanism for membrane fusion by evaluating the fusion inhibition ability of a series of conformationally restricted polar lipids. 2. Prepare and evaluate fusion promoters that are rationally designed to facilitate the stalk fusion mechanism. Two types of fusion promoters will be explored, (i) hydrophobic hexadecane dendrons that fill and stabilize the stalk interstitial voids, and (ii) spherical, ionic dendrimers that stabilize the highly curved surfaces of the stalk fusion intermediates. An effective promoter will be viewed as supporting evidence for the stalk mechanism, whereas negative results will require the model to be re-evaluated. 3. Prepare a series of dendrimer-steroid and dendrimer-liposome conjugates and evaluate if they have potential applications in gene therapy and drug delivery. 4. Use the accumulated data to formulate an improved molecular mechanism for biological membrane fusion.