Abstract A promising approach to tackle the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) could be small interfering (si)RNAs. So far it is unclear, which viral replication steps can be efficiently inhibited with siRNAs. Here, we report that siRNAs can target genomic RNA (gRNA) of SARS-CoV-2 after cell entry, and thereby terminate replication before start of transcription and prevent virus-induced cell death. Coronaviruses replicate via negative sense RNA intermediates using a unique discontinuous transcription process. As a result, each viral RNA contains identical sequences at the 5′ and 3′ end. Surprisingly, siRNAs were not active against intermediate negative sense transcripts. Targeting common sequences shared by all viral transcripts allowed simultaneous suppression of gRNA and subgenomic (sg)RNAs by a single siRNA. The most effective suppression of viral replication and spread, however, was achieved by siRNAs that targeted open reading frame 1 (ORF1) which only exists in gRNA. In contrast, siRNAs that targeted the common regions of transcripts were outcompeted by the highly abundant sgRNAs leading to an impaired antiviral efficacy. Verifying the translational relevance of these findings, we show that a chemically modified siRNA that targets a highly conserved region of ORF1, inhibited SARS-CoV-2 replication ex vivo in explants of the human lung. Our work encourages the development of siRNA-based therapies for COVID-19 and suggests that early therapy start, or prophylactic application, together with specifically targeting gRNA, might be key for high antiviral efficacy. Graphical Abstract Graphical Abstract Exclusive targeting of SARS-CoV-2 genomic RNA enables most efficient suppression of viral replication and virus-induced cell death.
【초록키워드】 COVID-19, SARS-CoV-2, therapy, Transcription, Prophylactic, severe acute respiratory syndrome Coronavirus, RNA, Replication, Spread, Severe acute respiratory syndrome, Region, Viral, viral replication, human lung, siRNA, sgRNA, antiviral efficacy, target, Viral RNA, respiratory, discontinuous transcription, SARS-CoV-2 replication, Coronavirus-2, Open reading frame, genomic RNA, conserved region, Ex vivo, acute respiratory syndrome, Frame, siRNAs, acute respiratory syndrome coronavirus, viral transcripts, cell entry, acute respiratory syndrome coronavirus-2, sequence, transcripts, 3′ end, sgRNAs, ORF1, gRNA, targeting, transcript, open reading frame 1, virus-induced cell death, approach, Prevent, effective, conserved, inhibited, replicate, unique, active against, translational, Verifying, viral transcript, 【제목키워드】 Spread, siRNA, SARS-CoV-2 RNA, genomic, targeting,