Cracking the Host Sugar Code: Insights into H5Nx Influenza A Virus Adaptation and Pathogenesis

Sugar-Viro will create advanced glycoscience tools to address critical questions in H5Nx influenza A virus (IAV) biology, aiming to enhance surveillance, inform antiviral development, and contribute to the fight against IAV infections. To initiate infection, respiratory pathogens like IAV must interact with complex carbohydrate structures, or glycans, present on the respiratory epithelium. However, virus-glycan interactions remain poorly understood due to the diversity, biosynthetic complexity, and multivalent presentation of host glycans. IAV, especially the H5Nx subtype, poses a continuous pandemic threat, recently spreading to a wider array of avian and mammalian hosts. This project will develop an integrated approach to systematically analyze how H5Nx IAV engages with host glycans, providing a framework for understanding virus-glycan interactions. IAVs adapt to new hosts by acquiring amino acid mutations in the hemagglutinin (HA), which binds to sialic acid receptors, and neuraminidase (NA), which cleaves these receptors. These mutations shift receptor specificity and necessitate balancing receptor binding and cleavage activities. My research will first characterize the glycome of the respiratory tracts of avian and mammalian hosts for H5Nx IAV, which will be a first (AIM 1a). This will inform the enzymatic synthesis of complex glycans, including both N- and O-linked glycan cores and glycolipids, going beyond the current state of the art (AIM 1b). Subsequently, I will conduct a detailed analysis of the glycan-binding properties of HA (AIM 2a) and NA (AIM 2b), by in depth binding analyses using complex glycans and novel tools to determine NA activity and specificity. To understand viral binding dynamics across species and tissue types, I will use multi-species, multi-organ tissue microarrays (AIM 3a) and assess glycan-specific functions in higher-order systems, including organoids (AIM 3b).