Mode of action of a new type of UDP-glucose analog against herpesvirus replication

Metabolic Enzymes in Viral Infection and Host Innate Immunity

Metabolic enzymes are central players for cell metabolism and cell proliferation. These enzymes perform distinct functions in various cellular processes, such as cell metabolism and immune defense. Because viral infections inevitably trigger host immune activation, viruses have evolved diverse strategies to blunt or exploit the host immune response to enable viral replication. Meanwhile, viruses hijack key cellular metabolic enzymes to reprogram metabolism, which generates the necessary biomolecules for viral replication. An emerging theme arising from the metabolic studies of viral infection is that metabolic enzymes are key players of immune response and, conversely, immune components regulate cellular metabolism, revealing unexpected communication between these two fundamental processes that are otherwise disjointed. This review aims to summarize our present comprehension of the involvement of metabolic enzymes in viral infections and host immunity and to provide insights for potential antiviral therapy targeting metabolic enzymes.

Flavonoids: Potent Inhibitors of Poliovirus RNA Synthesis

Some naturally occurring flavonoids, such as 3-methyl quercetin and Ro-090179, show potent anti-picornavirus activity. They inhibit poliovirus replication at concentrations 100-fold or 1000-fold lower than hydroxybenzyl-benzimidazole (HBB) and guanidine, respectively. Ro-090179 selectively blocks viral RNA synthesis in poliovirus-infected HeLa cells more strongly than 3-methyl quercetin and is therefore the most potent and selective inhibitor of poliovirus RNA synthesis described until now. In addition, Ro-090179 discriminates in its inhibition between plus- and minus-stranded RNA synthesis. Thus, analysis of the viral RNA made in poliovirus-infected cells when the compound is added late in the infection cycle, indicates that the synthesis of genomic RNA is potently blocked, whereas minus-stranded RNA synthesis is not inhibited. These findings make Ro-090179 a valuable compound for obtaining insight into the molecular mechanisms of poliovirus RNA replication.

6-(3,4-Dichlorophenoxy)-3-(ethylthio)-2-pyridincarbonitrile inhibits poliovirus uncoating

We investigated the mode of action of 6-(3,4-dichlorophenoxy-3-(ethylthio)-2-pyridincarbonitrile against poliovirus. This agent effectively blocked the synthesis of poliovirus proteins and RNA when it was added at the beginning of infection. Poliovirus attachment and internalization into HeLa cells were not inhibited in the presence of the compound; poliovirus uncoating was the target of its activity.