ver-155008 and Fish-Diseases

The heat-shock protein 70 (Hsp70) inhibitor, VER-155008 (VER), was explored as a potential antiviral agent for two RNA viruses important to fish aquaculture, viral hemorrhagic septicemia virus (VHSV) and infectious pancreatic necrosis virus (IPNV). Studies were done at a temperature of 14 °C, and with cell lines commonly used to propagate these viruses. These were respectively EPC from fathead minnow for VHSV and CHSE-214 from Chinook salmon embryo for IPNV. Additionally, both viruses were studied with the Atlantic salmon heart endothelial cell line ASHe. For both VHSV and IPNV, 25 μM VER impeded replication. This was evidenced by delays in the development of cytopathic effect (CPE) and the expression of viral proteins, N for VHSV and VP2 for IPNV, and by less production of viral RNA and of viral titre. As VER inhibits the activity of Hsp70 family members, these results suggest that VHSV and IPNV utilize one or more Hsp70s in their life cycles. Yet neither virus induced Hsp70. Surprisingly VER alone induced Hsp70, but whether this induction modulated VER's antiviral effects is unknown. Exploring this apparent paradox in the future should improve the usefulness of VER as an antiviral agent.

Topics: Animals; Cell Culture Techniques; Cell Line; Cyprinidae; Endothelial Cells; Fish Diseases; Fishes; HSP70 Heat-Shock Proteins; Purine Nucleosides; RNA Viruses; RNA, Viral; Salmon; Virus Replication

Grass carp (Ctenopharyngodon idella) hemorrhagic disease, caused by grass carp reovirus (GCRV), has been a serious problem in grass carp aquaculture for several decades. Characterization of the primary host factors associated with host-virus interaction is critical for understanding how a virus infects its host cell and these host factors can be antiviral targets. This study aimed to screen host factors that interacted with GCRV in the C. idella kidney (CIK) cells and used them as antiviral targets. Twelve proteins were identified by virus overlay protein binding assay and LC-MS-MS. Among these twelve proteins, Heat Shock Protein 70 (HSP70) was outstanding. Results of flow cytometry and immunofluorescence assay indicated that HSP70 was on the cell membrane. HSP70 was expressed at low levels preceding GCRV infection, but its expression was induced upon GCRV infection. Inhibition of HSP70's function by inhibitors (VER155008 and pifithrin-μ) maintained HSP70 on the cell surface in infected cells, however GCRV quantity was decreased in the CIK cells (compared with the control group, the maximum inhibition rate of the treatment group was close to 85%), suggesting that fully functional HSP70 was required for GCRV infection. Moreover, GCRV showed a dose dependent reduction by inhibiting the entry stage of the viral life cycle following treated with VER155008 and pifithrin-μ. VER + PIF (1:1) were used at 15 μM and the expression of GCRV-VP6 downregulated nearly to 90%, which revealed that HSP70 played an important role in GCRV entering into CIK cells. This work speculated that HSP70 might be a host factor in the process of GCRV infecting CIK cells, therefore, it might be a potential antiviral target for GCRV infection.

Topics: Animals; Antiviral Agents; Carps; Epithelial Cells; Fish Diseases; Fish Proteins; Gene Expression; Gene Expression Profiling; Host-Pathogen Interactions; HSP70 Heat-Shock Proteins; Kidney; Purine Nucleosides; Reoviridae; Reoviridae Infections; Sulfonamides; Virus Internalization