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

项目概要： 由新型冠状病毒SARS-CoV-2引起的COVID-19大流行对 美国报告的病例和死亡人数最多。改进 对COVID-19的了解将加速有效疗法的开发，这是必要的， 抗击SARS-CoV-2，包括其新变种。SARS-CoV-2人类受体ACE 2是疾病的核心 发病机制和潜在的治疗方法。该提案的重点是SARS-CoV-2的成像和治疗， 一种新开发的ACE 2靶向PET放射性示踪剂和S蛋白中和疗法。这些疗法 包括携带重组ACE 2（rACE 2）和单克隆抗体（mAb）5A 6 PLGA纳米颗粒 最近在加州大学旧金山分校开发的。虽然所提出的技术和疗法直接适用于SARS- CoV-2，它们也可能适用于未来的冠状病毒感染和其他由ACE 2驱动的疾病。 抑制，尤其是急性呼吸窘迫综合征（ARDS）。从ACE 2本身衍生的疗法也 在SARS-CoV-2变异体的情况下具有很高的影响，这些变异体逃避疫苗和基于mAb的药物。 我们最近鉴定了一种环状的，[68 Ga]-NOTA修饰的ACE 2抑制肽（[68 Ga]-NOTA-ACE 2 pep）， PET放射性示踪剂用于研究SARS-CoV-2感染及其体内治疗。这种放射性示踪剂是用 了解ACE 2抑制在COVID-19中的时间和位置，这对治疗感染者至关重要， 患者和识别肺、心脏、肾脏、胃肠道和中枢神经系统的疾病。 ACE 2特异性PET成像也将帮助我们了解rACE 2/mAb治疗的效果， 开发落后于疫苗的推出。在这个建议中，我们将首先优化一个放射性合成的 类似的18F标记的示踪剂，即[18F]AlF-NOTA-ACE 2 pep，并验证其体外性能（特异性 目标1）。在特异性目标2中，我们使用[18F]AlF-NOTA-ACE 2 pep对转基因小鼠中的ACE 2缺失进行成像，并在转基因小鼠中进行了检测。 COVID-19小鼠模型。最后，在具体目标3中，我们将开发纳米颗粒衍生的方法， rACE 2/5A 6，并证明当在SARS-CoV-2感染周围给予治疗时， 曝光时间。将使用[18 F]AlF-NOTA-ACE 2 pep在体内显示该治疗效果。3年R 01 建议优先考虑可以很快开发的方法和方法，以努力影响 COVID-19疫情尽快。 这项建议的主要研究者是大卫博士。Wilson，Robert Flavell，and Tejal Desai（UCSF） 和Sanjay Jain（约翰霍普金斯）;作为感染成像领域的领导者，Wilson博士和Jain博士 广泛地在一起。加州大学旧金山分校和约翰霍普金斯大学已经建立了关键的基础设施， 2019冠状病毒病。具体来说，Jain博士在约翰霍普金斯的BSL 3设施是世界上为数不多的地方之一， 可以进行所提出的SARS-CoV-2感染动物的PENPET-CT研究。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.