Thapsigargin inhibition of coronavirus PHEV replication by Ca2+ mediated metabolic reprogramming

Porcine hemagglutinating encephalomyelitis virus (PHEV), belonging to the genus Betacoronavirus, is one of the six coronaviruses that infect pigs, for which no effective drug or vaccine is commercially available. Here, we found that thapsigargin (Tg), an ER stress inducer, potently blocks PHEV replication in non-cytotoxic levels and the antiviral effect is long-lasting at least 60 h post-Tg exposure in different cells.

Time-of-addition assay demonstrated that Tg significantly inhibit PHEV replication in N2a cells when treated immediately before, during, or after virus infection. Tg does not directly interact with PHEV particles and transcriptome analysis reveals a unique antiviral mechanism of Tg through Ca2+ mediated metabolic reprogramming. Crucially, oral administration of Tg prolong the survival time and reduced virus titres in the brains of treated mice.