Targeted Imaging Agents Based on Synthetically Modified Viral Capsids

描述（由申请人提供）：定义明确的纳米级材料的可用性为疾病的诊断和治疗提供了令人兴奋的新方法。与小分子药物相比，这些结构的相对大的尺寸允许许多不同的组分组合成复杂的多功能装置。然而，由于缺乏合适的支架，这些材料在实践中难以生产，所述支架提供低毒性、在生物环境中的高稳定性以及用于建筑物附着的战略位点。 用于生物医学应用的模块。 为了满足这一需求，本文所述的研究计划将病毒的中空蛋白质壳转化为一系列靶向成像剂，用于心血管疾病的研究和诊断。这将通过结合弗朗西斯集团（加州大学伯克利分校化学系）的广泛的蛋白质修饰经验与UCSF分子和功能成像中心的心血管成像和microPET专业知识来实现。具体来说，我们将在无基因组的MS 2病毒衣壳外部安装基团，使它们定位于动脉粥样硬化的早期（靶向VCAM-1），中期（靶向巨噬细胞）和晚期（靶向纤维蛋白凝块）阶段。这些载体的内表面将用荧光发色团和长寿命放射性核素（如64 Cu）的螯合剂双重官能化。放射性示踪剂将允许使用PET对衣壳进行成像，并将有助于定量生物分布研究。荧光团将 允许在组织病理学染色期间检测和区分衣壳因子。初步研究已经表征了非靶向衣壳的基线生物分布特性，表明它们显示出出乎意料的长血液循环时间。 在拟定的研究中，将首先在健康小鼠中表征每种靶向药物的生物分布，以确定外部功能化对清除时间的影响。然后，它们将在ApoE（-/-）小鼠中成像，这些小鼠已被喂食高脂肪饮食不同的时间长度。将使用对比增强CT扫描以及切除区域的组织病理学验证体内蓄积部位。除了验证它们与适当的双分子靶点定位的能力外，我们还将确定这些药物是否能够区分动脉粥样硬化斑块形成的不同阶段。

DESCRIPTION (provided by applicant): The availability of well-defined nanoscale materials offers exciting new approaches for the diagnosis and treatment of disease. In contrast to small molecule drugs, the relatively large dimensions of these structures al- low many different components to be combined into a complex, multifunctional device. However, these materials have been difficult to produce in practice due to the lack of suitable scaffolds that offer low toxicity, high stability in biological settings, and strategic sites for the attachment of building blocks for biomedical applications. To fulfill this need, the research program described herein will convert the hollow protein shell of a virus into a series of targeted imaging agents for the study and diagnosis of cardiovascular disease. This will be accomplished by combining the extensive protein modification experience of the Francis group (UC Berkeley Chemistry Department) with the cardiovascular imaging and microPET expertise of the UCSF Center for Molecular and Functional Imaging. Specifically, we will install groups on the outside of genome-free MS2 viral capsids to cause them to localize at the early (targeting VCAM-1), middle (targeting macrophages), and late (targeting fibrin clots) stages of atherosclerosis. The inside surfaces of these carriers will be doubly functionalized with fluorescent chromophores and chelators for long-lived radionuclides (such as 64Cu). The radiotracers will allow the capsids to be imaged using PET, and will assist in quantitative biodistribution studies. The fluorophores will allow the detection and differentiation of the capsid agents during histopathological staining. Preliminary studies have already characterized the baseline biodistribution properties of untargeted capsids, indicating that they display unexpectedly long blood circulation times. In the proposed studies, the biodistribution of each targeted agent will first be characterized in healthy mice in order to determine the effects of external functionalization on clearance time. They will then be imaged in ApoE(-/-) mice that have been fed a high fat diet for varying lengths of time. Sites of in vivo accumulation will be verified using contrast-enhanced CT scans, as well as histopathology of excised regions. In addition to verifying their ability to localize with the appropriate bimolecular targets, we will determine whether the agents are capable of distinguishing the different stages of atherosclerotic plaque formation.