ACE2-targeted PET radiotracers for investigating spatiotemporal distribution of SARS-CoV-2 organ injury and therapy response.

项目总结： 由新型冠状病毒SARS-CoV-2引发的新冠肺炎大流行对 全球范围内报告的病例和死亡人数最多的是美国。改进 对新冠肺炎的理解将加速有效疗法的发展，这对于 抗击SARS-CoV-2及其新变种。SARS-CoV-2人类受体ACE2是疾病的中心 发病机制和潜在的治疗方法。这项建议侧重于SARS-CoV-2的成像和治疗 一种新开发的以血管紧张素转换酶2为靶点的PET放射性示踪剂和S-蛋白质中和疗法。这些疗法 包括携带重组ACE2(RACE2)和单抗(MAb)5A6 PLGA纳米粒 最近在加州大学旧金山分校开发的。虽然建议的技术和治疗方法直接适用于SARS- CoV-2，它们还可能适用于未来的冠状病毒感染和其他由ACE2驱动的疾病 抑制，尤其是急性呼吸窘迫综合征(ARDS)。源自ACE2本身的疗法也 在逃避疫苗和基于单抗的药物的SARS-CoV-2变种的背景下，具有很高的影响。 我们最近发现了一种环，[68Ga]-NOTA修饰的ACE2抑制肽([68Ga]-NOTA-ACE2pep)是一种 PET放射性示踪剂研究SARS-CoV-2感染及其体内治疗这种放射性示踪剂是用 目的是了解血管紧张素转换酶2抑制在新冠肺炎中的时机和位置，这对治疗感染至关重要 并识别肺、心脏、肾脏、胃肠道和中枢神经系统的疾病。 ACE2特异性的PET成像也将帮助我们了解rACE2/mAb治疗的效果，其 疫苗的研发一直落后于疫苗的推出。在这项提案中，我们将首先优化一种 类似的18F标记示踪剂，即[18F]Alf-NOTA-ACE2pep，并验证其体外性能(特异性 目标1)。在特定目标2中，我们使用[18F]Alf-NOTA-ACE2pep来成像转基因小鼠中的ACE2丢失和 新冠肺炎小鼠模型。最后，在特定目标3中，我们将开发纳米颗粒衍生方法来传递 RACE2/5A6，并展示了对SARS-CoV-2感染的抑制，当治疗在 曝光时间。使用[18F]Alf-NOTA-ACE2pep将在体内显示这种治疗效果。我们的三年期R01 提案确定了可以非常快速开发的方法和途径的优先顺序，以努力影响 尽快在新冠肺炎大流行。 该提案的主要调查者是大卫·M·威尔逊博士、罗伯特·弗拉维尔博士和特贾尔·德赛博士(加州大学旧金山分校)。 和Sanjay Jain(约翰斯·霍普金斯大学)；作为感染成像领域的领导者，威尔逊博士和Jain博士 广泛地结合在一起。加州大学旧金山分校和约翰·霍普金斯大学的关键基础设施已经到位，用于打击 新冠肺炎。具体地说，Jain博士位于约翰·霍普金斯大学的BSL3实验室是世界上少数几个 建议的SARS-CoV-2感染动物的正电子发射计算机断层扫描研究是可以进行的。因此，我们将利用 加州大学旧金山分校和约翰·霍普金斯大学的多个生产性实验室的优势，以完成拟议的工作。

PROJECT SUMMARY: The COVID-19 pandemic, caused by the new coronavirus SARS-CoV-2, has had a remarkable impact on public health worldwide with the largest number of cases and deaths reported in the United States. Improved understanding of COVID-19 will accelerate the development of effective therapeutics, which are necessary to fight SARS-CoV-2 including its new variants. The SARS-CoV-2 human receptor ACE2 is central to disease pathogenesis and potential therapies. This proposal focuses on the imaging and therapy of SARS-CoV-2 using a newly developed, ACE2-targeted PET radiotracer and S-protein neutralizing therapies. These therapies include PLGA nanoparticles bearing recombinant ACE2 (rACE2) and a monoclonal antibody (mAb) 5A6 recently developed at UCSF. Although the techniques and therapies proposed are directly applicable to SARS- CoV-2, they will also potentially apply to future coronavirus infections and other diseases driven by ACE2 suppression especially acute respiratory distress syndrome (ARDS). Therapies derived from ACE2 itself also have high impact in the context of SARS-CoV-2 variants that evade vaccines and mAb-based drugs. We recently identified a cyclic, [68Ga]-NOTA modified ACE2 inhibitory peptide ([68Ga]-NOTA-ACE2pep) as a PET radiotracer to study SARS-CoV-2 infection and its treatment in vivo. This radiotracer was developed with the goal of understanding the timing and location of ACE2 suppression in COVID-19, critical in treating infected patients and identifying disease in the lungs, heart, kidneys, gastrointestinal tract and central nervous system. ACE2-specific PET imaging will also help us understand the effects of rACE2/mAb therapies, whose development has lagged behind vaccine rollout. In this proposal, we will first optimize a radiosynthesis of an analogous 18F-labelled tracer namely [18F]AlF-NOTA-ACE2pep and validate its performance in vitro (Specific Aim 1). In Specific Aim 2, we use [18F]AlF-NOTA-ACE2pep to image ACE2 loss in transgenic mice and a COVID-19 murine model. Finally, in Specific Aim 3 we will develop nanoparticle-derived methods to deliver rACE2/ 5A6 and demonstrate suppression of SARS-CoV-2 infection, when therapy is administered around the time of exposure. This treatment effect will be shown in vivo using [18F]AlF-NOTA-ACE2pep. Our 3-year R01 proposal prioritizes methods and approaches that can be developed very quickly, in an effort to impact the COVID-19 pandemic as soon as possible. The principal investigators of this proposal are Drs. David M. Wilson, Robert Flavell, and Tejal Desai (UCSF) and Sanjay Jain (Johns Hopkins); as leaders in the field of infection imaging Drs. Wilson and Jain have worked extensively together. Key infrastructure is already in place at UCSF and Johns Hopkins for the fight against COVID-19. Specifically, Dr. Jain's BSL3 facility at Johns Hopkins is one of the few places in the world where the proposed PET-CT studies of SARS-CoV-2 infected animals can be performed. We will therefore harness the strengths of multiple productive laboratories at UCSF and Johns Hopkins to accomplish the proposed work.