Inhibitors of One or More Cellular Aurora Kinases Impair the Replication of Herpes Simplex Virus 1 and Other DNA and RNA Viruses with Diverse Genomes and Life Cycles

We utilized a high-throughput cell-based assay to screen several chemical libraries for inhibitors of herpes simplex virus 1 (HSV-1) gene expression. From this screen, four aurora kinase inhibitors were identified that potently reduced gene expression during HSV-1 lytic infection. HSV-1 is known to interact with cellular kinases to regulate gene expression by modulating the phosphorylation and/or activities of viral and cellular proteins. To date, the role of aurora kinases in HSV-1 lytic infection has not been reported. We demonstrated that three aurora kinase inhibitors strongly reduced the transcript levels of immediate-early (IE) genes ICP0, ICP4, and ICP27 and impaired HSV-1 protein expression from all classes of HSV-1, including ICP0, ICP4, ICP8, and gC. These restrictions caused by the aurora kinase inhibitors led to potent reductions in HSV-1 viral replication. The compounds TAK 901, JNJ 7706621, and PF 03814735 decreased HSV-1 titers by 4,500-, 13,200-, and 8,400-fold, respectively, when present in a low micromolar range. The antiviral activity of these compounds correlated with an apparent decrease in histone H3 phosphorylation at serine 10 (H3S10ph) during viral infection, suggesting that the phosphorylation status of H3 influences HSV-1 gene expression. Furthermore, we demonstrated that the aurora kinase inhibitors also impaired the replication of other RNA and DNA viruses. These inhibitors significantly reduced yields of vaccinia virus (a poxvirus, double-stranded DNA, cytoplasmic replication) and mouse hepatitis virus (a coronavirus, positive-sense single-strand RNA [ssRNA]), whereas vesicular stomatitis virus (rhabdovirus, negative-sense ssRNA) yields were unaffected. These results indicated that the activities of aurora kinases play pivotal roles in the life cycles of diverse viruses

SARS-CoV-2 Mac1 is an essential virulence factor

Several coronavirus (CoV) encoded proteins are being evaluated as targets for antiviral therapies for COVID-19. Included in this set of proteins is the conserved macrodomain, or Mac1, an ADP-ribosylhydrolase and ADP-ribose binding protein. Utilizing point mutant recombinant viruses, Mac1 was shown to be critical for both murine hepatitis virus (MHV) and severe acute respiratory syndrome (SARS)-CoV virulence. However, as a potential drug target, it is imperative to understand how a complete Mac1 deletion impacts the replication and pathogenesis of different CoVs. To this end, we created recombinant bacterial artificial chromosomes (BACs) containing complete Mac1 deletions (ΔMac1) in MHV, MERS-CoV, and SARS-CoV-2. While we were unable to recover infectious virus from MHV or MERS-CoV ΔMac1 BACs, SARS-CoV-2 ΔMac1 was readily recovered from BAC transfection, indicating a stark difference in the requirement for Mac1 between different CoVs. Furthermore, SARS-CoV-2 ΔMac1 replicated at or near wild-type levels in multiple cell lines susceptible to infection. However, in a mouse model of severe infection, ΔMac1 was quickly cleared causing minimal pathology without any morbidity. ΔMac1 SARS-CoV-2 induced increased levels of interferon (IFN) and interferon-stimulated gene (ISG) expression in cell culture and mice, indicating that Mac1 blocks IFN responses which may contribute to its attenuation. ΔMac1 infection also led to a stark reduction in inflammatory monocytes and neutrophils. These results demonstrate that Mac1 only minimally impacts SARS-CoV-2 replication, unlike MHV and MERS-CoV, but is required for SARS-CoV-2 pathogenesis and is a unique antiviral drug target.National Institutes of Health (NIH) grant P20GM103648 (RC) National Institutes of Health (NIH) grant 2P01AI060699 (LE) National Institutes of Health (NIH) grant P20GM113117 (ARF) National Institutes of Health (NIH) grant K22AI134993 (ARF) National Institutes of Health (NIH) grant R35GM138029 (ARF) National Science Foundation (NSF) grant 2135167 (RLU) University of Kansas General Research Fund (GRF) and Start-up funds (ARF) NIH Graduate Training at the Biology-Chemistry Interface grant T32GM132061 (CMK) University of Kansas College of Liberal Arts and Sciences Graduate Research Fellowship (CMK) Government of Spain (PID2019-107001RB-I00 AEI/FEDER, UE) LE European Commission (H2020-SC1-2019, ISOLDA Project nº 848166-2) LEN