TitleInhibition of SARS-CoV-2 in Vero cell cultures by peptide-conjugated morpholino oligomers.
Publication TypeJournal Article
Year of Publication2021
AuthorsRosenke, K, Leventhal, S, Moulton, HM, Hatlevig, S, Hawman, D, Feldmann, H, Stein, DA
JournalJ Antimicrob Chemother
Date Published2021 01 19
KeywordsAnimals, Antiviral Agents, Cell Survival, Cell-Penetrating Peptides, Chlorocebus aethiops, COVID-19, Cytopathogenic Effect, Viral, Morpholinos, SARS-CoV-2, Vero Cells, Virus Replication

BACKGROUND: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.

Alternate JournalJ Antimicrob Chemother
PubMed ID33164048
PubMed Central IDPMC7717290