SBIR PA22-176 - RNA aptamers for rapid response to COVID-19 variants

SBIR PA22-176 - 用于快速响应 COVID-19 变体的 RNA 适体

• 批准号: 10758405
• 负责人: Hong Yan Liu
• 金额: $ 27.55万
• 依托单位: DOTQUANT, LLC
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-30 至 2024-03-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10758405
• 关键词: SBIR; PA22; 176; RNA; aptamers

ABSTRACT The COVID-19 pandemic caused by SARS-CoV-2 viruses has had an unprecedented disruptive global impact. Although vaccination has been expected to end the spread, the fast mutations have increased the breakthrough infection rates in the fully vaccinated population. RNA viruses are known to have very high rates of mutation and evolution. The high rate of mutation is correlated with virulence modulation and the ability to escape host immunity posting an urgent need for treatments that can keep up with the virus mutations. On the molecular level, spike (S) protein receptor binding domain (RBD) and angiotensin-converting enzyme 2 (ACE2) are key mediators for viral entry, therefore pharmacological disruption of S1 RBD binding to ACE2 could be an effective treatment against SARS-CoV-2. Indeed, neutralization antibodies against the S protein have been developed and are used in clinics. Unfortunately, it is difficult for antibody engineering to keep up with the virus evolution. The Delta variant is twice as contagious as the previous variants, whereas the Omicron variant exhibits more mutations in the spike protein than other variants. These variants have raised CDC's concerns due to the risks of immune escape and increased transmissibility. The need for effective drugs against the fast mutating variants can not be met by antibodies because the production of therapeutic antibodies is time-consuming and costly. In this context, nucleic acid-based aptamers, also known as `chemical antibodies' have the potential to address this challenge. Aptamers are selected using an in vitro chemical combinatorial approach, systematic evolution of ligands by exponential enrichment (SELEX), and offer advantages over antibodies to address the problem of mutating viruses because of the fast selection and chemical production, easy chemical modification, high thermostability, and low immunogenicity. Although RNA aptamer is sensitive to nucleases and renal clearance, 2'-fluoro-pyrimidine modification has significantly increased the resistance nucleases, while multivalent aptamers or conjugation to PEGs can increase aptamer sizes and consequently the circulation time. In our preliminary studies, we have selected a series of RNA aptamers targeting the wild-type SARS-CoV-2 S1RBD protein and invented a proprietary approach to generate chemical-modified serum-stable RNAs at high yield and low cost. The selected aptamers show the universal inhibitory effect to RBD-ACE2 binding for WT and variants (Alpha, Beta, Gamma, and Omicron) but not the Delta variant yet. In this project, we will address the Delta variant and optimize our current aptamers and the new anti-Delta aptamer into a bispecific format (avoid rapid renal clearance). We will reach our goals through the following specific aims:1) Screening and characterization of aptamers against the Delta variant and optimization of aptamers by forming bivalent structures, and 2) Evaluation of the antiviral activity. The antiviral capability will be assessed in pseudovirus as well as live infectious viruses through our established agreement with NIAID. Beyond the specific aptamers, we will establish a platform and our ability for quick responses to virus mutations. In terms of responding to fast-mutating infectious diseases, developing aptamer-based therapeutics as an alternative to antibodies is similar to developing mRNA vaccines over conventional inactivated virus vaccines because both aptamers and mRNAs can be screened/designed quickly.

摘要 由SARS-CoV-2病毒引起的COVID-19大流行对全球造成了前所未有的破坏性影响。 尽管人们一直期望接种疫苗能结束传播，但快速突变增加了突破口。 全面接种疫苗人群的感染率。已知RNA病毒具有非常高的突变率， 进化高突变率与毒力调节和逃避宿主的能力有关 免疫力的提高迫切需要能够跟上病毒突变的治疗方法。的分子 S蛋白受体结合域（RBD）和血管紧张素转换酶2（ACE 2）是关键 因此，药理学破坏S1 RBD与ACE 2的结合可能是一种有效的方法。 治疗SARS-CoV-2。事实上，针对S蛋白的中和抗体已经被开发出来 并用于临床。不幸的是，抗体工程很难跟上病毒的进化。 德尔塔变种的传染性是以前变种的两倍，而奥密克隆变种的传染性更强。 刺突蛋白中的突变比其他变体。这些变异引起了疾病预防控制中心的关注， 免疫逃逸和传染性增加的可能性需要针对快速突变变体的有效药物 不能通过抗体来满足，因为治疗性抗体的生产耗时且昂贵。在 在这种情况下，基于核酸的适体，也称为“化学抗体”，具有解决这一问题的潜力。 挑战.使用体外化学组合方法选择适体， 通过指数富集（SELEX）的配体，并提供优于抗体的优势，以解决 变异病毒由于选择和化学生产速度快，易于化学修饰， 热稳定性和低免疫原性。虽然RNA适体对核酸酶和肾清除敏感， 2 '-氟-嘧啶修饰显著增加了核酸酶的抗性，而多价适体 或与PEG缀合可以增加适体大小，并因此增加循环时间。在我们的初步调查中 研究中，我们选择了一系列靶向野生型SARS-CoV-2 S1 RBD蛋白的RNA适体， 发明了一种专有方法，以高产率和低成本产生化学修饰的血清稳定RNA。 所选择的适体显示出对WT和变体的RBD-ACE 2结合的普遍抑制作用（α， Beta、Gamma和Omicron），但还没有Delta变体。在这个项目中，我们将解决Delta变体， 将我们目前的适体和新的抗Delta适体优化为双特异性形式（避免快速肾功能衰竭）。 清除）。我们将通过以下具体目标实现我们的目标：1）筛选和表征 针对Delta变体的适体和通过形成二价结构优化适体，和2）评估 的抗病毒活性。将在假病毒和活感染性病毒中评估抗病毒能力 通过我们与NIAID的既定协议。除了特定的适体，我们将建立一个平台， 我们对病毒突变的快速反应能力。在应对快速变异的传染病方面， 开发以适体为基础的疗法作为抗体的替代品，类似于开发mRNA疫苗 因为可以筛选/设计适体和mRNA， 快