PROMOTERS AND INHIBITORS OF MEMBRANE FUSION

膜融合的促进剂和抑制剂

• 批准号: 6386417
• 负责人: BRADLEY D. SMITH
• 金额: $ 16.26万
• 依托单位: UNIVERSITY OF NOTRE DAME
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-05-01 至 2003-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6386417
• 关键词: biophysics; calorimetry; chemical conjugate; chemical structure function; chemical synthesis; conformation; hydropathy; inhibitor /antagonist; lipids; liposomes; membrane fusion; molecular polarity; phospholipids; polymers; stereochemistry; stop flow technique

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.

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。 这项工作将为健康和健康科学带来实际和智力上的好处。 从实践的角度来看，新的融合催化剂的开发将是杂交瘤研究，基因治疗和药物递送领域的一个受欢迎的技术进步;而融合抑制剂可能是有用的一系列疾病领域，特别是机会性感染的新的治疗剂。 将有大量的智力贡献，因为启动子和抑制剂的设计，以测试我们目前的理解膜融合在分子水平上。 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、异质的基质，并且难以描绘控制分子因子。 然而，有很好的证据表明脂质体通过类似的机制融合，并且从模型研究中获得的知识可用于解释融合蛋白如何工作。 此外，详细了解脂质体融合本身是临床上有用的目标，因为脂质体被用作药物递送载体。目前，茎假说是最被接受的，膜融合的一般机制。 然而，这是很难证明这一机制，因为短暂的融合中间体是难以观察和表征。 对茎机制的仔细研究表明，具有特定拓扑结构和极性的分子应该能够稳定或破坏推定的融合中间体，从而促进或抑制融合。 本申请的具体目的是：1.通过评估一系列构象限制性极性脂质的融合抑制能力来测试最近假设的膜融合的扩展构象机制。 2.制备和评估融合促进剂，合理设计，以促进茎融合机制。 将探索两种类型的融合促进剂，（i）填充和稳定茎间隙空隙的疏水性十六烷树枝状分子，和（ii）稳定茎融合中间体的高度弯曲表面的球形离子树枝状聚合物。 有效的启动子将被视为支持茎机制的证据，而负面的结果将需要重新评估模型。 3. 制备了一系列树枝状大分子-类固醇和树枝状大分子-脂质体偶联物，并评价它们在基因治疗和药物递送方面的潜在应用。 4. 利用积累的数据制定一个改进的生物膜融合的分子机制。