Transient knockdown of the ACE-2 Receptor using the RALA Technology for COVID-19

RNAi疗法有可能改变医疗干预措施，过去两年批准了两种产品，用于治疗危及生命的疾病。RNAi治疗的目的是为了治疗目的而暂时减少缺陷基因。这是一个快速增长的市场，有109种基于RNAi的疗法正在进行临床试验(2018年7月)[特恩布尔2020]。然而，围绕RNAi疗法仍然存在一些问题，包括到达适当的组织，然后确保细胞内递送到目的地。最近的研究还表明，那些有潜在健康状况的人，如糖尿病、高血压或吸烟者，肺上皮细胞中ACE-2受体的数量增加。研究表明，新冠肺炎利用血管紧张素转换酶-2受体进入细胞，以产生更多的病毒颗粒，从而感染更多血管紧张素转换酶-2受体阳性细胞[库巴2005]。ACE-2受体在许多生物学功能中发挥作用，但如果能够在短时间内降低表达，就可以降低病毒的传染性，帮助平衡朝着健康恢复的方向发展。RNAi可以用来暂时减少这种ACE-2受体的表达，但前提是有合适的递送系统。因此，在这次新冠肺炎捐赠募集中，PHION明确地与医疗保健这一特定主题保持一致，因此开发了一种安全的RNAi传递解决方案，该解决方案不会进一步加剧免疫系统，优先将治疗药物输送到肺部，并且具有成本效益，最终使RNAi疗法得以广泛采用。创新的核心是使用一种名为Rala的多肽，这种多肽旨在将RNAi浓缩成纳米颗粒(NPs)，这些纳米颗粒具有穿过细胞膜、高效地逃脱内体将货物运送到细胞质所需的特性。在旨在减少ACE-2表达的RNAi和Rala肽之间形成的NPs不需要冷链储存，可以在不失去功能的情况下储存数月。这项拟议的6个月的初步研究旨在证明Rala/RNAi NPs可以减少人肺细胞中ACE-2受体的表达，然后在体内短期内。Impact资金的延长建立在最初项目的基础上，通过询问体内Rala/RNAi NPs的安全性概况。这3个月的延期是为了完成一项研究，该研究测量了体内单次和多次注射Rala/RNAi NPs后的毒理学和免疫学反应。这项额外研究的结果将产生一个具有商业价值的数据包，证明Rala技术是多么安全。最初的项目和进一步的影响研究将提供证据，这对于确保这种疗法向I期试验发展的未来投资至关重要。这种短效RNAi疗法对任何针对ACE-2受体的冠状病毒爆发都具有潜在的作用。

RNAi therapeutics have the potential to transform healthcare interventions as evidenced by the approval of 2 products in the last 2 years for life threatening diseases. RNAi therapy is designed to transiently reduce a defective gene for therapeutic purposes. It is a rapidly growing market with 109 RNAi based therapeutics in clinical trials (July 2018) \[Turnbull 2020\]. However, there are still issues that surround the RNAi therapeutics which include getting to the appropriate tissue and then ensuring intracellular delivery to the destination site. Recent studies have also indicated that those with underlying health conditions such as diabetes, high-blood pressure or smokers have an increased number of ACE-2 receptors in the lung epithelium \[Leung 2020\]. Studies have revealed that COVID-19 uses the ACE-2 receptor to enter cells in order to produce more viral particles that can infect more ACE-2 receptor positive cells \[Kuba 2005\]. The ACE-2 receptor plays a role for many biological functions but if expression could be lowered for a short period of time it could reduce the infectivity of the virus and help tip the balance towards healthy recovery. RNAi could be used to transiently reduce expression of this ACE-2 receptor but only if there is an appropriate delivery system. Therefore with clear alignment to the specific theme of healthcare in this COVID-19 grant call, pHion have developed a solution for RNAi delivery that is safe, does not further exacerbate the immune system, preferentially delivers the therapeutic to the lung and is cost-effective, ultimately enabling widespread adoption of the RNAi therapy. The innovation centres around the use of a peptide termed RALA that is designed to condense RNAi into nanoparticles (NPs) that have the properties necessary to cross cell membranes, escape endosomes delivering the cargo to the cytoplasm with high efficiency. The NPs formed between the RNAi which is designed to reduce ACE-2 expression and the RALA peptide do not require cold chain storage can be stored for many months without losing functionality. The proposed 6 month pilot study is designed to demonstrate that the RALA/RNAi NPs can reduce ACE-2 receptor expression in human lung cells and then in vivo for a short period of time. The extension for impact funding builds upon the initial project by interrogating the safety profile of the RALA/RNAi NPs in vivo. This 3 month extension is designed to complete a study that measures both the toxicological and immunological response following single and multiple injections of the RALA/RNAi NPs in vivo. The outputs from this additional study will result in a commercially valuable data pack that demonstrates how safe the RALA technology is. The original project and the further impact study will provide evidence which is critical to secure future investment for the development of this therapeutic towards a Phase I trial. This short-acting RNAi therapy holds potential for any coronavirus outbreak that targets the ACE-2 receptor.