The multifaceted pathways of astrovirus entry and egress - PROJECT SUMMARY Astroviruses are a major cause of pediatric diarrhea worldwide. Despite causing one of the most common early childhood infections, astroviruses are one of the least studied enteric RNA viruses. We previously discovered that the virus infects small intestinal goblet cells, specialized epithelial cells that secrete mucus. Few studies have investigated viral infection in goblet cells due to the lack of cell-specific models. Because the mechanisms by which viruses replicate inside of goblet cells are completely unknown, my lab is interested in addressing 1) how do astroviruses enter cells with highly dynamic apical membranes? and 2) what role does mucus secretion play in viral egress? We have established new in vitro models and tools to address these questions and have built a strong and collaborative investigative team with complementary expertise that will ensure the success of these projects. To evaluate receptor-mediated and fluid-phase endocytosis entry pathways into goblet cells, we will use a combination of CRISPR-Cas9 engineering, biochemical analysis, and high-resolution microscopy. We will use a similar suite of techniques as well as cryo-electron microscopy to define the egress pathway of astrovirus from goblet cells via mucus secretion. In addition to murine and human astroviruses, other respiratory and enteric viruses have also been shown to target goblet cells for infection. Thus, our work aims to initially provide foundational knowledge on the basic biology of astroviruses before shedding light on key host pathways in goblet cells that are co-opted by viruses from other families, including influenza and SARS-CoV2. Completion of these studies will provide the first major insights into the virus-host interactions at the apical membrane surface of intestinal goblet cells, which will pave the way for the future development of targeted drug treatments for the numerous viruses that target this unique cell population.
