Research Project 1: Discovery and dissection of virus-host interactions and pathogenetic mechanisms

Viruses interact with and hijack a vast array of cellular molecules and pathways to facilitate their multiplication and spread, while also reprograming infected cells to release pathogenic viral factors (‘viral toxins’) that could be independently targeted with vaccines and therapeutics to reduce disease severity. Given that virus-host

interactions can provide new and broadly shared Achilles’ heels against emerging viruses and inform the rapid development of in vitro and in vivo models to test novel medical countermeasures, uncovering these interactions is essential to pandemic preparedness. However, critical gaps exist in our foundational knowledge of the

mechanisms of viral infection and pathogenesis for nairoviruses, hantaviruses, and paramyxoviruses. The overarching goal of Project 1 is to discover and dissect host factors and pathways critical for infection and pathogenesis by our prototype viruses—Crimean-Congo hemorrhagic fever virus (CCHFV), Andes virus (ANDV),

and Menangle virus (MenPV)—and additional divergent viruses from these families. In Aim 1, our interdisciplinary research team will discover and validate entry receptors and other critical host factors using complementary CRISPR/Cas9-based genetic and time-resolved proteomic and phosphoproteomic screening

approaches, and selected hits will be assessed for their roles in infection and pathogenesis in vivo with gene- edited rodent models of infection. Utilizing a suite of virological, cell-biological, and quantitative proteomics assays, in Aim 2 we will elucidate the mechanisms by which our prototype viruses exploit validated host factors

and pathways, identify host interactors of viral proteins, and map the functional surfaces of viral and host proteins confirmed to interact. These findings will be expanded to divergent members of each virus family. Finally, in Aim 3, our team will define the role of CCHFV and hantavirus glycoprotein-induced vascular leak in pathogenesis by

defining host factors and molecular interfaces essential for barrier dysfunction and identifying markers of endothelial dysfunction in animal models and humans. Key deliverables of Project 1 include novel reagents, including recombinant vesicular stomatitis viruses and variable heavy chain-only antibodies to facilitate host

factor discovery and validation, and critical data to support immunogen engineering efforts in Projects 2–3, antibody profiling and discovery in Project 4, and animal model development in Core D. This project will contribute to PROVIDENT's objectives by generating fundamental knowledge about virus-host interactions that

influence nairovirus, hantavirus, and paramyxovirus infection, virulence, and pathogenesis.