Uncovering and harnessing connected metabolic pathways essential to virus infection.

Project Summary / Abstract Polyamines are small molecules abundant in eukaryotic cells that function in transcription and translation. While these molecules are important for cellular function, emerging evidence suggests that polyamine metabolism is intricately linked to diverse metabolic pathways within the cell. The interconnectedness of metabolic pathways has significant consequences for cells, as well as pathogens. We previously demonstrated that polyamines support replication of diverse RNA viruses and that upon detection of infection, cells induce polyamine depletion. Polyamine depletion limits infection by bunyaviruses (Rift Valley fever virus [RVFV] and La Crosse virus [LACV]), flaviviruses (Zika virus [ZIKV] and dengue viruses), and enteroviruses (Coxsackievirus B3 [CVB3], rhinovirus), among several others. We hypothesize that these distinct virus families subvert cellular metabolism, specifically through polyamines, to support virus replication. Here, we will investigate (1) how viruses utilize polyamines at distinct stages of replication, (2) how viruses confront polyamine depletion, and (3) how polyamine biosynthesis connects to other metabolic pathways to support virus replication. We use the RVFV, ZIKV, and CVB3 model systems in our work because these viruses represent three evolutionarily distant viruses with different replicative and structural differences. While each of these viruses relies on polyamines for replication, we find that how they use polyamines is different. Now, we will expand on this work to understand the roles of distinct polyamines during virus infection, including roles in virion structure, cellular attachment, and genome replication. We will also use these model systems to understand how these viruses manipulate polyamine metabolism. Finally, we will investigate how the differences in polyamine utilization may reflect how polyamines affect other cellular metabolic pathways, including lipid and cholesterol synthesis. This work will illuminate the connectedness of polyamine biosynthesis to other metabolic pathways and how viruses rely on these interconnected pathways for successful replication. This work will highlight fundamental roles for polyamines in virus replication and in cellular metabolism.