Inhibition of SARS-CoV-2 Replication by a Small Interfering RNA Targeting the Leader Sequence

• Published in: Viruses Vol. 13; no. 10; p. 2030
• Main Authors: Tolksdorf, Beatrice, Nie, Chuanxiong, Niemeyer, Daniela, Röhrs, Viola, Berg, Johanna, Lauster, Daniel, Adler, Julia M., Haag, Rainer, Trimpert, Jakob, Kaufer, Benedikt, Drosten, Christian, Kurreck, Jens
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 08.10.2021; MDPI
• Subjects: 5' Untranslated Regions; 5′-UTR; Coronaviruses; COVID-19; Gene expression; Genomes; Hepatitis; Homology; Infections; leader sequence; Mutation; Nucleotide sequence; Proteins; Replication; RNA polymerase; RNA-mediated interference; RNAi therapy; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; siRNA; Vaccine development; Viral infections; Viruses; United States > US; Germany
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v13102030

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected almost 200 million people worldwide and led to approximately 4 million deaths as of August 2021. Despite successful vaccine development, treatment options are limited. A promising strategy to specifically target viral infections is to suppress viral replication through RNA interference (RNAi). Hence, we designed eight small interfering RNAs (siRNAs) targeting the highly conserved 5′-untranslated region (5′-UTR) of SARS-CoV-2. The most promising candidate identified in initial reporter assays, termed siCoV6, targets the leader sequence of the virus, which is present in the genomic as well as in all subgenomic RNAs. In assays with infectious SARS-CoV-2, it reduced replication by two orders of magnitude and prevented the development of a cytopathic effect. Moreover, it retained its activity against the SARS-CoV-2 alpha variant and has perfect homology against all sequences of the delta variant that were analyzed by bioinformatic means. Interestingly, the siRNA was even highly active in virus replication assays with the SARS-CoV-1 family member. This work thus identified a very potent siRNA with a broad activity against various SARS-CoV viruses that represents a promising candidate for the development of new treatment options.