Subversion of intercellular coupling during respiratory virus infection

PROJECT SUMMARY Coronavirus infections comprise 15 - 30% of common colds, with four human coronaviruses circulating seasonally. While respiratory and gastrointestinal symptoms are usually self-limiting, increased disease severity, such as bronchitis and pneumonia, can occur. This increased coronavirus disease severity is also highlighted by the most recent coronavirus outbreak, emphasizing the importance of understanding mechanisms of coronaviral replication and propagation. Interestingly, coronaviruses have been reported to disrupt intercellular coupling, suggesting a conserved mechanism used to promote coronaviral replication and propagation. This is unsurprising, as mechanical and metabolic coupling contribute to the cell-intrinsic antiviral immune response. Epithelial barriers established in part by tight junctions prevent viral access to receptors required for cell entry and the underlying tissue. Meanwhile, gap junction intercellular communication facilitates the spread of immune signaling molecules to prime the cell-intrinsic innate antiviral response in neighboring cells. Despite these antiviral roles of junctional complexes, how coronaviruses target and perturb host junctional complexes to facilitate viral infection and spread remains unknown. My proposed research will address this gap in knowledge through investigating coronaviral-mediated manipulation of epithelial cell mechanical and metabolic coupling and the mechanism through which this occurs. Aim 1: Determine mechanisms of coronaviral-mediated alterations to epithelial cell mechanical coupling. Organization of tight junction complexes following coronaviral infection will be assessed, along with the sufficiency of individual viral proteins to induce pathological remodeling of tight junction complexes and the mechanism through which tight junction remodeling occurs. Aim 2: Delineate the mechanism through which coronaviruses perturb epithelial cell metabolic coupling. Signaling pathways driving decreased gap junction function during coronavirus infection will be identified, and the sufficiency of coronaviral proteins to impair metabolic coupling will be determined. The effect of gap junction intercellular communication on coronaviral spread and disease severity will also be assessed. Completion of this project will reveal mechanisms of how coronavirus infection affects both mechanical and metabolic intercellular coupling. Ultimately, this work will broaden our understanding of coronavirus pathogenesis, identifying molecular substrates for novel anti-coronaviral therapeutics. Specifically, targeting coronavirus-mediated mechanisms of cell junction perturbation may serve as a viable future direction for antivirals to decrease recovery time by limiting viral spread while preserving host antiviral immune responses.