Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.
Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR, USA.
J Antimicrob Chemother. 2021 Jan 19;76(2):413-417. doi: 10.1093/jac/dkaa460.
As the causative agent of COVID-19, SARS-CoV-2 is a pathogen of immense importance to global public health. Development of innovative direct-acting antiviral agents is sorely needed to address this virus. Peptide-conjugated morpholino oligomers (PPMO) are antisense compounds composed of a phosphorodiamidate morpholino oligomer covalently conjugated to a cell-penetrating peptide. PPMO require no delivery assistance to enter cells and are able to reduce expression of targeted RNA through sequence-specific steric blocking.
Five PPMO designed against sequences of genomic RNA in the SARS-CoV-2 5'-untranslated region and a negative control PPMO of random sequence were synthesized. Each PPMO was evaluated for its effect on the viability of uninfected cells and its inhibitory effect on the replication of SARS-CoV-2 in Vero-E6 cell cultures. Cell viability was evaluated with an ATP-based method using a 48 h PPMO treatment time. Viral growth was measured with quantitative RT-PCR and TCID50 infectivity assays from experiments where cells received a 5 h PPMO treatment time.
PPMO designed to base-pair with sequence in the 5' terminal region or the leader transcription regulatory sequence region of SARS-CoV-2 genomic RNA were highly efficacious, reducing viral titres by up to 4-6 log10 in cell cultures at 48-72 h post-infection, in a non-toxic and dose-responsive manner.
The data indicate that PPMO have the ability to potently and specifically suppress SARS-CoV-2 growth and are promising candidates for further preclinical development.
作为 COVID-19 的病原体，SARS-CoV-2 对全球公共卫生具有重要意义。为了解决这一病毒问题，迫切需要开发创新的直接作用抗病毒药物。肽偶联的吗啉代寡核苷酸（PPMO）是一种反义化合物，由一个磷酸二酰胺吗啉代寡核苷酸通过共价键与一个穿透细胞的肽连接而成。PPMO 无需任何输送辅助即可进入细胞，并通过序列特异性空间位阻来降低靶向 RNA 的表达。
设计了针对 SARS-CoV-2 5'-非翻译区基因组 RNA 序列的 5 个 PPMO 和一个随机序列的阴性对照 PPMO，并对其进行了评价。每个 PPMO 均评估了其对未感染细胞活力的影响及其对 Vero-E6 细胞培养物中 SARS-CoV-2 复制的抑制作用。使用基于 ATP 的方法在 48 小时 PPMO 处理时间内评估细胞活力。通过在细胞接受 5 小时 PPMO 处理时间的实验中使用定量 RT-PCR 和 TCID50 感染性测定来测量病毒生长。
设计与 SARS-CoV-2 基因组 RNA 5'末端区域或前导转录调节序列区域的序列碱基配对的 PPMO 非常有效，可在感染后 48-72 小时内以非毒性和剂量反应的方式使细胞培养物中的病毒滴度降低多达 4-6 对数。
数据表明，PPMO 具有强烈且特异性抑制 SARS-CoV-2 生长的能力，是进一步临床前开发的有前途的候选药物。
