mRNA-encoded Cas13 as a pan-respiratory antiviral

项目摘要 已知有200多种病毒感染人类，它们占全球死亡率的6.6%。我们有 针对10种病毒的约91种药物和仅针对16种病毒的疫苗。基因重组和抗原性改变 疫苗效力面临挑战;这在COVID大流行期间得到了明确证明。现行药品 发展的重点是小分子和中和抗体，这需要高剂量或频繁的 重新给药以获得功能结果，并且也受到抗原变化的挑战。因此， 以满足对更高效和更广谱的抗病毒药物的需求。为了满足这一需求，我们建议 一种完全不同的抗病毒开发范例，一种mRNA编码的可激活的RNA酶，Cas 13， 泛呼吸治疗平台。Cas 13代表一种可编程的RNA酶，它可以直接靶向和 降解多种病毒信使或基因组RNA。合成的mRNA被用来传递RNA酶，因为它 允许瞬时、非病毒递送，与其他基因治疗载体相比具有改善的安全性1。给定 用单一mRNA编码的Cas 13为基础的药物实现泛呼吸结果不是微不足道的关键步骤， 为了实现这一目标，可以通过关注三种最具影响力的呼吸道病毒来实现， RSV、流感和SARS-CoV-2。到目前为止，我们的团队是第一个证明mRNA编码的 Cas 13在体外和体内通过基于雾化器的肺递送对抗小鼠模型和SARS中的流感- CoV-2在仓鼠模型中的研究，我们最近发表在《自然生物技术》上。为了实现一种药物 RSV、流感和SARS-CoV-2存在需要应对的重要问题/挑战。因此我们 将确定多种呼吸道病原体的最佳Cas 13物种，并研究 Cas 13对每种病毒的作用。我们还将证明单一药物对RSV、流感和SAR的疗效- CoV-2在小鼠和仓鼠模型中的体内试验，作为个体病毒感染的治疗，在共 感染（流感和SAR-CoV-2），并减少SARS-CoV-2的传播。

Project Summary There are over 200 viruses known to infect humans and they contribute to 6.6% of global mortality. We have approximately 91 drugs for 10 viral species and vaccines for only 16. Reassortment and antigenic changes pose challenges to vaccine efficacy; this has clearly been demonstrated during the COVID pandemic. Current drug development is focused on small molecules and neutralizing antibodies, which require high doses or frequent re-dosing to obtain functional outcomes and have also been challenged by antigenic changes. Thus, it is crucial to address the need for higher efficiency and broader spectrum antivirals. To address this need we are proposing an entirely different paradigm for antiviral development, an mRNA-encoded activatable RNase, Cas13, as a platform for a pan-respiratory treatment. Cas13 represents a programmable RNase that can directly target and degrade multiple viral messenger or genomic RNA. Synthetic mRNA is being used to deliver the RNase, as it allows for transient, non-viral delivery, with an improved safety profile over other gene therapy vectors1. Given achieving pan-respiratory results with a single mRNA-encoded Cas13 based drug is not trivial, critical steps towards that goal can be achieved by focusing on the three most impactful respiratory viruses in circulation, RSV, influenza and SARS-CoV-2. To date, our team was the first to demonstrate efficacy of mRNA-encoded Cas13 in vitro and in vivo via nebulizer-based lung delivery against influenza in the mouse model and SARS- CoV-2 in the hamster model in our recent publication in Nature Biotechnology. In order to achieve one drug for RSV, influenza and SARS-CoV-2 there are important questions/challenges that will need to be met. Thus, we will determine the optimal Cas13 species for multiple respiratory pathogens and investigate the mechanism of action of Cas13 for each virus. We will also demonstrate single drug efficacy against RSV, influenza and SAR- CoV-2 in vivo in mouse and hamster models, given as treatments for the individual viral infections, during co- infection (influenza and SAR-CoV-2), and to mitigate transmission of SARS-CoV-2.