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 全球公共卫生领域，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，这对于 对抗 SARS-CoV-2，包括其新变种。 SARS-CoV-2 人类受体 ACE2 是疾病的核心 发病机制和潜在的治疗方法。该提案重点关注 SARS-CoV-2 的成像和治疗 一种新开发的、针对 ACE2 的 PET 放射性示踪剂和 S 蛋白中和疗法。这些疗法 包括带有重组 ACE2 (rACE2) 和单克隆抗体 (mAb) 5A6 的 PLGA 纳米颗粒 最近在加州大学旧金山分校开发。尽管所提出的技术和疗法直接适用于 SARS- CoV-2，它们也有可能适用于未来的冠状病毒感染和由 ACE2 驱动的其他疾病 抑制尤其是急性呼吸窘迫综合征（ARDS）。源自 ACE2 本身的疗法也 在逃避疫苗和单克隆抗体药物的 SARS-CoV-2 变体的背景下具有重大影响。 我们最近鉴定了一种环状[68Ga]-NOTA 修饰的 ACE2 抑制肽（[68Ga]-NOTA-ACE2pep）作为 PET 放射性示踪剂用于研究 SARS-CoV-2 感染及其体内治疗。该放射性示踪剂的开发 了解 COVID-19 中 ACE2 抑制的时间和位置，这对于治疗感染至关重要 患者并识别肺、心脏、肾脏、胃肠道和中枢神经系统的疾病。 ACE2特异性PET成像还将帮助我们了解rACE2/mAb疗法的效果，其 开发滞后于疫苗的推出。在这个提案中，我们将首先优化放射合成 类似的 18F 标记示踪剂即 [18F]AlF-NOTA-ACE2pep 并验证其体外性能（具体 目标1）。在具体目标 2 中，我们使用 [18F]AlF-NOTA-ACE2pep 对转基因小鼠中的 ACE2 丢失进行成像，并 COVID-19 小鼠模型。最后，在具体目标 3 中，我们将开发纳米粒子衍生的方法来交付 rACE2/5A6 并证明当在周围进行治疗时可抑制 SARS-CoV-2 感染 曝光时间。这种治疗效果将使用[ 18 F]AlF-NOTA-ACE2pep在体内显示。我们的3年R01 提案优先考虑可以快速开发的方法和途径，以努力影响 COVID-19 尽快大流行。 该提案的主要研究人员是博士。大卫·M·威尔逊 (David M. Wilson)、罗伯特·弗拉维尔 (Robert Flavell) 和 Tejal Desai (加州大学旧金山分校) 和 Sanjay Jain（约翰·霍普金斯大学）；作为感染成像领域的领导者。威尔逊和贾恩曾工作过 广泛地在一起。加州大学旧金山分校 (UCSF) 和约翰霍普金斯大学 (Johns Hopkins) 已准备好关键基础设施，以应对 新冠肺炎。具体来说，Jain 博士位于约翰·霍普金斯大学的 BSL3 设施是世界上为数不多的几个可提供 BSL3 设施的地方之一。 可以对 SARS-CoV-2 感染动物进行拟议的 PET-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高效实验室的优势来完成拟议的工作。

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.