Phage-based targeted imaging probes and their application to vascular diseases

描述（由申请人提供）：我们的总体目标是创建和测试基于蛋白笼纳米颗粒（PCN）的新一代细胞/组织靶向MRI造影剂。其目的是显着提高在体内血管疾病中检测和成像分子水平事件的能力。该提案是一项多学科的努力，结合了心血管医学，血管生物学，MRI，病毒学，合成无机和纳米材料化学方面的专业知识。基于强有力的初步结果，在体外和体内，我们的方法将结合联合收割机使用噬菌体P22衣壳作为生物模板，用于构建高性能的多功能MR造影剂。基于P22的蛋白笼纳米颗粒（PCN）的内表面将用于空间限制聚合物高性能Gd基T1造影剂的独特家族。PCN的外部将用于细胞特异性靶向配体的多价展示以及组织靶向和血液半衰期的额外体内选择和优化。这种方法的优点是对优化弛豫率所需的物理参数的实质性控制，同时在单个系统中结合有效的组织靶向和体内发现的潜力。虽然这些平台可以应用于广泛的疾病，但该应用的重点将是血管疾病（动脉粥样硬化）。该提案的具体目标是（i）开发具有优化弛豫率曲线的基于蛋白笼纳米颗粒的造影剂，以及（ii）将组织特异性靶向配体掺入PCN和体内选择用于组织靶向和延长血液半衰期的噬菌体，以及（iii）翻译靶向蛋白笼纳米颗粒以在建立的小鼠模型中成像血管疾病。还将评价Gd毒性和P22免疫原性问题。针对新鲜人体组织的P22噬菌体文库的直接筛选提供了用于鉴定新型组织营养肽的替代方法。使用最先进的设施创建和评价这些基于PCN的材料作为功能性MR造影剂，将为迭代过程提供快速和直接的反馈，以创建下一代高性能功能性MRI造影剂。该项目是三个有着实质性合作历史的团体之间的合作;道格拉斯（密歇根州立大学），麦康奈尔（斯坦福大学），和乔治（亚拉巴马大学）。其他人包括Frank（NIH）、Dalman（斯坦福大学）、Tsao（斯坦福大学）、Contag（斯坦福大学）、Uchida（MSU）和Zajac（亚拉巴马）将作为合作者或顾问参与，该团队将共同收集成功完成既定目标所需的广泛专业知识和经验。

DESCRIPTION (provided by applicant): Our overall goal is to create and test a new generation of cell/tissue- targeted MRI contrast agents based on protein cage nanoparticles (PCNs). The aim is to significantly increase the ability to detect and image molecular level events in vascular disease in vivo. This proposal is a multidisciplinary effort, combining established expertise in cardiovascular medicine, vascular biology, MRI, virology, synthetic inorganic and nano-materials chemistry. Based on strong preliminary results, both in vitro and in vivo, our approach will combine the use of bacteriophage P22 capsids as biotemplates for construction of high performance multifunctional MR contrast agents. The interior surface of the P22-based protein cage nanoparticles (PCN) will be used to spatially confine a unique family of polymeric high performance Gd-based T1 contrast agents. The exterior of the PCN will be used for multivalent display of cell-specific targeting ligands and additional in vivo selection and optimization of tissue targeting and blood half-life. The advantage of this approach is a substantial control over the physical parameters required to optimize relaxivity while at the same time incorporating effective tissue targeting and the potential for in vivo discovery in a single system. While these platforms can be applied to a broad range of diseases, the focus of this application will be on vascular disease (atherosclerosis). The specific objectives of this proposal are (i) the development of protein cage nanoparticle-based contrast agents with optimized relaxivity profiles and, (ii) the incorporation of tissue specific targeting ligands to the PCN and in vivo selection of phage for tissue targeting and extended blood half-life, and (iii) the translation of targeted protein cage nanoparticles to image vascular diseases in established mouse models. Issues of Gd toxicity and P22 immunogenicity will also be evaluated. Direct screening of the P22 phage library against fresh human tissue provides an alternative approach for identifying novel tissue-trophic peptides. Creation and evaluation of these PCN-based materials as functional MR contrast agents using state-of the-art facilities will provide rapid and direct feedback for an iterative process to create the next generation of high performance functional MRI contrast agents. The project is collaboration between three groups who have a history of substantial collaboration; Douglas (MSU), McConnell (Stanford University), and Privilege (University of Alabama). Others including Frank (NIH), Dalman (Stanford), Tsao (Stanford), Contag (Stanford), Uchida (MSU), and Zajac (Alabama) will participate as either collaborators or consultants and together this team gathers the breadth of expertise and experience necessary for the successful completion of the stated goals.