Study On The Regulation Of Pyrimidine Biosynthetic Pathway On The Replication Of Pest Des Petits Ruminants Virus

Peste des petits ruminants(PPR)is a severe infectious disease caused by peste des petits ruminants virus(PPRV).It is listed as a Class A severe animal infectious disease that must be reported by the World Health Organization.Cellular nucleotides can be synthesized de novo through a series of enzymatic reactions or recycled through salvage pathways in vivo.Since pyrimidine bases are an essential raw material for viral DNA/RNA replication,broad-spectrum antiviral drugs have taken targeting of the pyrimidine nucleotide synthesis pathway as a research hotspot and a potential antiviral strategy for the development of antiviral drugs in recent years.Dihydroorotate dehydrogenase(DHODH)and Orotidylate decarboxylase(ODCase)are key enzymes in de novo pyrimidine biosynthesis.DHODH inhibitors exhibit antiviral activities against different viruses attributing to the depletion of nucleosides necessary for replication of the viral genome.Beyond suppression of viral RNA synthesis,DHODH inhibitors have been demonstrated to provoke expression of interferon-stimulated genes(ISGs),which may also contribute to the antiviral effects of these compounds.The results showed that BQR and LFM,two specific inhibitors of DHODH enzyme,and 6-AU,an inhibitor of ODCase enzyme,were respectively verified at the nucleic acid,protein and viral particle levels of PPRV in HEK 293 T cell line and goat alveolar macrophages in a dose-dependent manner by qPCR,Western Blot and plaque.Certainly,the compound-mediated inhibition of PPRV replication could be reversed by adding uridine into the culture medium.Interfering with the enzyme activity RNAi can also impairs the replication of PPRV,and supplementing the enzyme inhibitor does not have the ability to inhibit the proliferation of the virus;Similarly,loss of DHODH-mediated inhibition of PPRV replication could be reversed by adding uridine into the culture medium.we found these inhibitors exerted their anti-PPRV effects via targeting DHODH to impair pyrimidine nucleotide pool.In addition,the induction of ISGs is independent of the classical JAK-STAT pathway,and Combination of BQR with interferons(IFNs)exerts enhanced ISG induction and anti-PPRV activity.The aim is to reveal an unconventional novel mechanism of crosstalk between nucleotide biosynthesis pathways and cellular antiviral immunity in inhibiting PPRV replication.Taken together,these results provided theoretical basis for studying the antiviral activity of these inhibitor compounds against susceptible hosts and their antiviral effect in combination with vaccines.