Regulation of Pathologic Inflammasome Responses to SARS-CoV-2

Project Summary Acute respiratory distress syndrome (ARDS) causes COVID-19 fatalities and is linked to uncontrolled release of pro-inflammatory cytokines, including interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF). Blockade of IL-1/IL-6 receptor signaling has shown success in treating severe COVID-19, but the molecular cues initiating excessive production of these cytokines remains unclear. A major source of IL-1 is the inflammasome, a supramolecular protein complex formed in response to two innate immune stimuli that executes IL-1β release. Meta-analysis of patient single-cell RNA sequencing data reveals exacerbated expression of IL1B and inflammasome-related genes in severe, but not mild, COVID-19. Co-culture of primary human airway epithelia (HAE) and primary human leukocytes during SARS-CoV-2 infection promotes IL-1β release, while infection in either cell type alone does not. These conditions also promote IL-6 release in an IL-1-dependent manner, highlighting how inflammasome activation and cell-cell communication amplify this inflammatory response. Furthermore, infected HAE undergo lytic cell death and secrete inflammasome-activating damage-associated molecular patterns (DAMPs). Therefore, the scientific goal of this proposal is to understand how SARS-CoV-2 infection promotes pathologic inflammasome responses with the central hypothesis that damage from dying, infected airway epithelial cells potentiate detrimental IL-1β release. Aim 1 will determine which inflammasome(s) mediate harmful IL-1β responses during SARS-CoV-2 infection in vivo and identify the tissue(s) from which this response is derived. Aim 2 will define the mechanism of SARS-CoV-2-mediated cell death in airway epithelial cells and its relationship with inflammasome-mediated cell death in myeloid cells using an established primary human co-culture system. Aim 3 will identify DAMPs released by infected primary human airway epithelial cells that stimulate inflammasome response via an unbiased multi-omics approach. These studies will define how damage caused by viral infection propagates inflammation and its role in disease, opening avenues for therapeutic targeting and identifying biomarkers related to pathologic inflammation in COVID-19. My goal is to become a tenured faculty member at a major research university with a research program studying fatal and emerging viral pathogens. My group will focus its efforts on understanding the innate immune response to viruses that regularly threaten human health and pinpoint pattern recognition receptor (PRR) ligands that lead to detrimental patient outcomes. Using a combined approach of primary human cell culture models, organismal murine models, and mechanistic molecular biology, I will identify readily translatable molecular targets to treat human viral diseases. Herein, I outline both a scientific vision and a plan acquire new skills through collaboration with local faculty, the support of my community and my advisory committee, and formal coursework to enhance my abilities further, creating a framework for my success as an independent investigator.