Development of High Throughput Screening and High Content Platforms for La Crosse Virus

Authors

• SC Ogden
• YM Ahn
• A Medina
• N Ibrahim
• N Martinez
• EM Lee

Abstract

The recent global pandemic has highlighted the pressing need for antiviral drug discovery tools in the effort to prevent future burdens on healthcare infrastructure and human health. At least ten RNA virus families were identified as having pandemic potential, including families in the negative-sense RNA virus order Bunyavirales. La Crosse virus (LACV) is known to cause pediatric encephalitis with only palliative care options available, emphasizing the need for relevant model systems and development of antiviral therapeutics. Bunyavirales genomes encode an endonuclease that utilizes a “cap-snatching” mechanism to cap the end viral transcripts. A similar influenza virus mechanism has been shown to be a druggable target by the FDA approved drug baloxavir marboxil. Thus, we believe the bunyavirales endonuclease presents an investigative opportunity for antiviral discovery. Previous efforts established an indirect signal detection method for antiviral compounds using a cytoprotective effect (CPE) assay; however, these assays may lack the sensitivity required to drive medicinal chemistry. Here, we developed a 1536-well, high content screening (HCS) platform based on direct detection of LACV for antiviral screening. We observed a differential effect of known anti-LACV compounds in indirect (e.g. CPE) vs direct (e.g. HCS) methods and further examined assay readouts by screening a library of 752 anti-infective compounds with both platforms. To validate the LACV endonuclease as a druggable target, we paired the HCS LACV assay with an NCATS developed LACV endonuclease biochemical assay and used both to screen additional NCATS libraries. Thus, we were able to identify compounds with single digit micromolar efficacy.

Scientific Focus Area: Virology

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