VIRUS BASED BIO-IMAGING & THERAPEUTIC DELIVERY SYSTEMS

基于病毒的生物成像

• 批准号: 6520256
• 负责人: MARK j YOUNG
• 金额: $ 21.56万
• 依托单位: MONTANA STATE UNIVERSITY - BOZEMAN
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6520256
• 关键词: acidity /alkalinity; binding proteins; binding sites; bioimaging /biomedical imaging; contrast media; disulfide bond; drug delivery systems; ionic bond; laminin; magnetic resonance imaging; microcapsule; nanotechnology; oxidation reduction reaction; protein engineering; protein structure; site directed mutagenesis; technology /technique development; virion; virus assembly; virus protein

Many viruses form stable self-assembled protein cages that function to store, protect and transport nucleic acid. We have previously shown that the cage structure of viruses can be used as constrained reaction vessels for the encapsulation and release of a wide range of materials other than its native RNA genome. In this way virus protein cages can be thought of as nanometer sized containers able to encapsulate other molecules through well-defined chemical interactions. The current proposal will explore the use of these virus cage structures for encapsulation and targeted delivery of therapeutic agents as well as development of these cages as magnetic resonance imaging contrast agents based on our demonstrated ability to engineer the coat protein. The principle objective of this proposal is to develop a model viral system for the use of virus cage structures in the high- density packing and release of therapeutic materials (molecules and polymers). Packaging within the virus can be driven by electrostatic complementarily between the inner protein interface and the relevant therapeutic material(s). One objective will be to extend the range of therapeutic materials that can be entrapped within the viral protein cage by engineering the electrostatic properties of the inner surface of the protein cage. A second major objective is to develop viral protein cages as potential magnetic resonance imaging contrast agents by engineering the inherent metal binding sites on the virion for binding 180 molecules of the paramagnetic Gd(III) ion. A third major objective is to express peptide 11 from the laminin protein on the outer surface of the virion and to determine its effectiveness at specifically targeting viral cages to cells expressing laminin-binding protein. A fourth major objective is to utilize inherent structural transitions in the virion to engineer new well defined chemical switches (based on redox potential and pH) to induce gating for selective entrapment and release of therapeutic materials. Virion gating results in the reversible opening/closing of 60 separate 20Angstrom units holes in the protein cage. We propose to use site-directed mutagenesis to engineer disulfide linkages and altered pH gating switches at these pores and test for their ability to entrap and release therapeutic materials.

许多病毒形成稳定的自组装蛋白质笼子，其功能是储存、保护和运输核酸。我们之前已经证明，病毒的笼状结构可以用作约束反应容器，用于封装和释放除其天然RNA基因组外的多种物质。通过这种方式，病毒蛋白笼可以被认为是纳米大小的容器，能够通过定义明确的化学相互作用封装其他分子。目前的提案将探索使用这些病毒笼结构来封装和靶向递送治疗剂，以及基于我们已经证明的设计外壳蛋白的能力，开发这些笼作为磁共振成像造影剂。本提案的主要目标是开发一种模型病毒系统，用于在高密度包装和释放治疗材料（分子和聚合物）中使用病毒笼结构。病毒内部的包装可以由内部蛋白质界面和相关治疗材料之间的互补静电驱动。一个目标将是通过设计蛋白质笼内表面的静电特性来扩大可以被包裹在病毒蛋白笼内的治疗材料的范围。第二个主要目标是通过设计病毒粒子上固有的金属结合位点来结合180个顺磁性Gd（III）离子分子，从而开发病毒蛋白笼作为潜在的磁共振成像造影剂。第三个主要目标是在病毒粒子的外表面从层粘连蛋白表达肽11，并确定其特异性靶向病毒笼到表达层粘连蛋白结合蛋白的细胞的有效性。第四个主要目标是利用病毒粒子固有的结构转变来设计新的明确的化学开关（基于氧化还原电位和pH值），以诱导选择性捕获和释放治疗物质的门控。病毒粒子门控导致蛋白质笼中60个独立的20埃单位孔的可逆打开/关闭。我们建议使用位点定向诱变来设计这些孔中的二硫键和改变pH门控开关，并测试它们捕获和释放治疗物质的能力。