Mechanisms and Treatment of SARS-CoV-2 induced Lung Endothelial Injury

项目总结/摘要 2019冠状病毒病（COVID-19）是由冠状病毒引起的一种毁灭性的全身炎症综合征 SARS-CoV-2在过去的一年里在美国导致了超过50万人死亡， 在很大程度上归因于急性肺损伤（ALI）或急性呼吸窘迫综合征的发展 （ARDS）。SARS-CoV-2进入细胞需要SARS-CoV-2刺突蛋白直接结合到主要的 宿主蛋白酶-TMPRSS 2和血管紧张素转换酶2（ACE-2）受体，其表达于 多种宿主细胞类型。开发有效的疫苗来预防SARS-CoV-2的传播， 这是一个巨大的进步，将有助于遏制COVID-19大流行，但令人担忧的变种的出现 如B1.1.7、P1和B1.351等，它们能逃避疫苗诱导的体液中和反应， 免疫应答强调了迫切需要开发新的治疗方法来补充疫苗接种的努力。 基于我们的挑衅性支持数据，我们已经制定了总体假设，SARS-CoV-2 诱导的肺内皮损伤是COVID-19诱导的适应不良炎性损伤的必要因素， 成为治疗目标。我们提出了以下具体目标：在目标1中，我们将定义 COVID-19诱导的ALI/ARDS的肺内皮损伤机制。我们将测试假设， 肺内皮损伤程度是多重SARS总体致病性和死亡率的关键决定因素， CoV-2变种。我们将建立SARS-CoV-2诱导的肺血管损伤和代偿性肺内皮细胞 使用两种互补的人源化ACE 2小鼠模型进行再生，EC特异性遗传谱系追踪， VE-钙粘蛋白的遗传稳定性和单细胞RNA测序。在目标2中，我们将定义有效性和最佳 两种靶向药物治疗策略预防和缓解SARS-CoV的时间窗 2诱导肺内皮损伤。我们将检验工程化的可溶性hACE-2肽具有 在减少肺内皮损伤以及长期使用中比野生型hACE-2肽具有更高的治疗功效， 通过防止病毒进入和传播多种SARS-CoV-2变异体进行EC重编程。我们将测试 推论假设，并且使用修饰的IL-1受体拮抗剂靶向抑制IL-1 β信号传导， 对多个SARS-CoV 2诱导的前馈炎症环和内皮损伤的保护作用 变体。我们将使用两种hACE-2小鼠模型，并比较不同的递送途径（腹膜内愈合与 静脉内），并确定治疗干预的最佳时间窗。

PROJECT SUMMARY / ABSTRACT Coronavirus disease 2019 (COVID-19) is a devastating systemic inflammatory syndrome caused by the coronavirus SARS-CoV-2 which has resulted in over 500,000 deaths in the US during the past year, with this high rate of mortality being attributed in large part to the development of Acute Lung Injury (ALI) or Acute Respiratory Distress Syndrome (ARDS). SARS-CoV-2 entry into cells requires the direct binding of the SARS-CoV-2 spike (S)-protein to the principal host protease-TMPRSS2 and the angiotensin converting enzyme 2 (ACE-2) receptors which are expressed in multiple host cell types. The development of efficacious vaccines to prevent the spread of SARS-CoV-2 represents a tremendous advance that will help curb the COVID-19 pandemic, however the emergence of variants of concern such as the B1.1.7, P1 and B1.351 which can evade the neutralizing responses of the vaccine-induced humoral immune response underscores the urgent need to develop novel therapeutics to complement the vaccination efforts. Based on our provocative Supporting Data, we have formulated the overarching hypothesis that SARS-CoV-2 induced lung endothelial injury is a requisite element of COVID-19 induced maladaptive inflammatory injury that can be therapeutically targeted. We propose the following specific aims: In Aim 1, we will define the nature and underlying mechanisms of lung endothelial injury underlying COVID-19-induced ALI/ARDS. We will test the hypothesis that the degree of lung endothelial injury is a key determinant of the overall pathogenicity and mortality of multiple SARS- CoV-2 variants. We will establish SARS-CoV-2-induced lung vascular injury and compensatory lung endothelial regeneration using two complementary humanized ACE2 mouse models, EC-specific genetic lineage tracing, genetic stabilization of VE-cadherin and single cell RNA-Sequencing. In Aim 2, we will define the efficacy and optimal temporal windows for two targeted pharmacological therapeutic strategies in preventing and resolving SARS-CoV- 2 induced lung endothelial injury. We will test the hypothesis that an engineered soluble hACE-2 peptide has a higher therapeutic efficacy than the wildtype hACE-2 peptide in reducing lung endothelial injury as well as long-term EC reprogramming by preventing viral entry and dissemination of multiple SARS-CoV-2 variants. We will test the corollary hypothesis and that targeted inhibition of IL1β-signaling using a modified IL-1 Receptor antagonist is protective against the feed-forward inflammatory loop and endothelial injury induced by multiple SARS-CoV2 variants. We will use two hACE-2 mouse models as well as compare distinct routes of delivery (intratracheal versus intravenous) and identify the optimal temporal windows for the therapeutic intervention.