Mathematical Modeling and Experimental Analysis of Spatial Division of Labor in Ocular Antiviral Defense - Project Summary To prevent Herpes Simplex Keratitis (HSK), an inflammatory corneal disease that is a common cause of blindness, corneal epithelial cells must limit the early spread of HSV-1 infection before immune cells infiltrate the eye. Early HSV-1 infection results in clusters of infected cells and localized inflammation, forming a viral microenvironment (VME). Our recent findings reveal that viral-induced translational inhibition prevents infected cells from producing type I interferons (IFN-I) or mounting an antiviral response, which raises questions about what drives the formation of the VME. Recent studies suggest that cells can transfer cyclic GMP-AMP (cGAMP), a second messenger generated in response to cytosolic DNA, to adjacent cells via gap junctions, potentially initiating IFN-I production in neighboring cells. However, the role of this transfer in driving corneal antiviral defense remains unclear. This project tests the central hypothesis that epithelial tissues spatially decouple the sensing of viral infection, the production of IFN-I, and the antiviral response, leading to a localized viral microenvironment that collaboratively contains the virus. The transfer of cGAMP between cells and the localized spread of cytokines suggest that the VME is composed of three distinct cell states: infected cells, neighboring cells, and distal cells. In Aim 1, we will use high-throughput proteomics and functional antiviral assays to investigate how each of these cell states assumes unique roles within the VME. Secondly, while the concept of cGAMP transfer has been qualitatively described, important biophysical properties—such as diffusion coefficient, spatial range, export rate, and how these are affected by viral infection and gap junction density—are still unknown. In Aim 2, we will integrate biophysical theory, simulations, analytical biochemistry, and live-cell microscopy to quantify cGAMP export rates and spatial spread as a function of viral replication rates and gap junction density. Finally, while the proposed cGAMP and IFN-I signaling relay offers a potential framework for understanding VME formation, a spatiotemporal mathematical model will help predict the key factors that govern the race between viral spread and host defense. In Aim 3, we will develop a PDE-based model to simulate how viral replication, cGAMP transfer, host translation, and IFN-I sensing impact viral containment. Parameter sensitivity analysis will identify crucial factors for effective viral suppression, which we will validate through live-cell imaging, pharmacological manipulation, and studies in HSV-1-infected mice with specific deficiencies in VME components. Our research bridges molecular, cellular, and tissue-level processes to study how communities of cells mount effective antiviral defenses that individual cells cannot achieve alone. Leveraging our expertise in biophysical theory, proteomics, live-cell fluorescence microscopy, in vivo mouse models, and mathematical modeling, we are uniquely positioned to address fundamental questions about the mechanisms driving tissue- scale antiviral defenses.
