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.

抽象的 由SARS-COV-2病毒引起的Covid-19大流行具有前所未有的破坏性全球影响。 尽管预计疫苗接种将结束蔓延，但快速突变增加了突破 全面疫苗接种人群的感染率。 RNA病毒的突变发生率很高，并且 进化。高突变速率与毒力调制和逃脱宿主的能力相关 免疫力发布迫切需要可以跟上病毒突变的治疗。在分子上 水平，尖峰（S）蛋白受体结合结构域（RBD）和血管紧张素转换酶2（ACE2）是钥匙 病毒进入的介体，因此S1 RBD与ACE2结合的药理破坏可能是有效的 针对SARS-COV-2的治疗。确实，已经开发了针对S蛋白的中和抗体 并用于诊所。不幸的是，抗体工程很难跟上病毒的进化。 增量变体的传染性是以前的变体的两倍，而Omicron变体则显示更多 与其他变体相比，峰值蛋白的突变。由于风险，这些变体引起了CDC的关注 免疫逃逸和增加的可传播性。需要对快速突变变体进行有效药物 由于治疗性抗体的产生是耗时且昂贵的，因此无法通过抗体满足。在 这种情况，基于核酸的适体，也称为“化学抗体”有可能解决这一点 挑战。使用体外化学组合方法选择适体 指数富集（SELEX）的配体，并提供了比抗体的优势来解决 由于选择快速和化学生产，易于化学修饰，高较高，突变病毒 热稳定性和低免疫原性。尽管RNA适体对核酸酶和肾脏清除敏感，但 2'-氟吡啶胺的修饰已显着增加了耐药性核酸酶，而多价适体 或与钉子的共轭可以增加适体大小，从而增加循环时间。在我们的初步中 研究，我们选择了一系列针对野生型SARS-COV-2 S1RBD蛋白的RNA适体和 发明了一种专有方法，以高产量和低成本生成化学改性的血清稳定RNA。 选定的适体显示了对WT和变体的RBD-ACE2结合的通用抑制作用（Alpha，Alpha， Beta，Gamma和Omicron），但尚未达到三角洲的变体。在这个项目中，我们将讨论三角洲的变体， 将当前的适体和新的抗Delta适体优化为双特异性格式（避免快速肾脏 清除）。我们将通过以下特定目的实现目标：1）筛选和表征 通过形成二价结构和2）评估的适体和适体的优化 抗病毒活性。抗病毒能力将在假病毒和活传染病中评估 通过我们与Niaid达成的既定协议。除了特定的适体外，我们还将建立一个平台和 我们对病毒突变的快速反应的能力。在应对快速爆发的传染病方面 开发基于适体的疗法作为抗体的替代方法类似于开发mRNA疫苗 在常规的灭活病毒疫苗上，因为可以筛选/设计适体和mRNA 迅速地。