Amaryllidaceae Alkaloids Screen Unveils Potent Anticoronaviral Compounds and Associated Structural Determinants.

Betacoronaviruses encompass a spectrum of respiratory diseases, from common cold caused by the human coronavirus (HCoV)-OC43 to life-threatening severe acute respiratory syndrome (SARS)-CoV-2. Addressing the constant need for novel antiviral compounds, we turned to the exploration of 40 plant-specialized metabolites produced by the medicinal plant family Amaryllidaceae, known to produce lycorine, a strong antiviral alkaloid. The present screen included 35 alkaloids with representatives of 8 ring-type structures.

RNA replication-independent, DNA linearization-dependent expression of reporter genes from a SARS-CoV-2 replicon-encoding DNA in human cells.

Replicons, derived from RNA viruses, are genetic constructs retaining essential viral enzyme genes while lacking key structural protein genes. Upon introduction into cells, the genes carried by the replicon RNA are expressed, and the RNA self-replicates, yet viral particle production does not take place. Typically, RNA replicons are transcribed in vitro and are then electroporated in cells.

Mammalian cells-based platforms for the generation of SARS-CoV-2 virus-like particles.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of COVID-19. Though many COVID-19 vaccines have been developed, most of them are delivered via intramuscular injection and thus confer relatively weak mucosal immunity against the natural infection. Virus-Like Particles (VLPs) are self-assembled nanostructures composed of key viral structural proteins, that mimic the wild-type virus structure but are non-infectious and non-replicating due to the lack of viral genetic material.