# data[].attributes.title
Neuroimmune mechanisms of coronavirus-induced lung inflammation and airway dysfunction

# data[].attributes.funder_divisions[]
National Heart Lung and Blood Institute (NHLBI)

# data[].attributes.abstract
The global impact of the COVID-19 pandemic has been profound, with nearly 800 million infections and seven million deaths worldwide. With the majority of fatalities resulting from respiratory failure, there is a pressing need to understand the factors that promote respiratory dysfunction following infection. The current paradigm centers on immunopathological mechanisms behind disease, but fails to incorporate how sensory neurons change during infection and contribute to the hallmark immune dysregulation and airway inflammation that characterize severe COVID-19. Airway sensory neurons are robustly activated by inflammatory mediators, pathogens and noxious irritants to modulate respiratory tone and initiate defense reflexes like cough, mucus production and bronchoconstriction. They also regulate the immune response to pathogens in the lung and become aberrantly activated during airway inflammation, thereby exacerbating reflex symptoms that contribute to morbidity. However, whether they play a role in the pathogenesis of coronavirus disease has not been studied, despite the potential to impact our understanding of airway physiology and identify new avenues for treatment. This proposal will test the following hypotheses: 1) that lung-innervating sensory neurons regulate the immune response to promote airway inflammation in coronavirus infection and 2) during infection, these cells undergo functional changes that contribute to respiratory dysfunction. Using the MHV-A59 mouse coronavirus infection model, our preliminary data support this hypothesis by demonstrating that the systemic ablation of TRPV1+ sensory neurons improves airway function while attenuating mortality and disease in infected mice. I will expand on these results by performing a specific, targeted ablation of the lung-innervating sensory neurons to elucidate their role in coronavirus disease pathology. I will determine if lung-innervating sensory neurons regulate airway inflammation by learning and performing spectral flow-cytometry to profile and quantify pulmonary immune cells, while separately measuring viral titer, neuropeptide and inflammatory cytokine concentrations in the lungs of infected, airway sensory neuron-ablated and intact mice. To understand how MHV-A59 infection modulates airway sensory neuron function to promote respiratory disease, I will acquire expertise in two-photon calcium imaging and electrophysiology to characterize their phenotypic changes in MHV-A59 infected animals. Lastly, I will measure oxygen saturation, breathing rates, respiratory mechanics and airway hyperreactivity in sensory neuron-ablated and intact mice to understand how these cells contribute to respiratory dysfunction. These studies will define the contribution of lung-innervating sensory neurons to coronavirus disease pathogenesis and lay the groundwork for discovering new treatments for respiratory disease.

# data[].attributes.title
Implementation partner-guided strategy to promote accuracy in ICU prognostication

# data[].attributes.funder_divisions[]
National Heart Lung and Blood Institute (NHLBI)

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Accurately predicting whether patients will live or die is an essential task in critical care medicine. Yet such predictions are often incorrect based on specific patient characteristics. We and others found that Acute Physiology and Chronic Health Evaluation (APACHE), Sequential Organ Failure Assessment (SOFA), and other prognostic tools overestimate the risk of death for certain groups of patients. Because the incidence of serious cardiac or respiratory critical illnesses is so high, the consequences of this error are significant for clinical decision making, research, and health policy. Given that APACHE II alone has been included in >10,000 studies, an entire medical literature may imperfectly measure the effectiveness of ICU treatments. Furthermore, the use of SOFA in ICU triage policies, such as during the COVID-19 pandemic, may propagate variability in health outcomes by incorrectly withholding life-saving ICU treatments from some patients.  There are two key knowledge gaps that limit a solution including a lack of understanding of how measurement errors arise in these prognostic tools and the absence of ICU prognostic tools that are free of such errors. Filling these gaps will promote high-quality ICU care and access to it, as well as ICU research.  Our goal is to develop a novel ICU mortality risk prediction model with accurate performance across all patient groups. To mitigate measurement error, we will combine state-of-the-art methods with the necessary supervision and contextual grounding provided by multidisciplinary advisors (critical care, bioethics, data science). Utilizing data from >100,000 patients broadly representative of the US population from 23 ICUs at Duke and Medical University of South Carolina, this project has three aims: (1) Identify mechanisms of systematic measurement error in commonly used ICU mortality risk prediction models; (2) Develop an accurate in-hospital mortality prediction model for all groups of critically ill patients; and (3) Conduct a real-world feasibility study of the new model within our electronic health record.   The expected outcomes of this study, which addresses NHLBI’s key objectives to reduce variability in health outcomes and improve care by leveraging the power of data science, are two-fold. First, to our knowledge, this will be the first study to identify mechanisms of measurement error in current ICU mortality risk prediction models and to include variables that reflect the living situation of patients in ICU risk prediction—innovations that will serve as a conceptual foundation for future work. Second, the new model will have an immediate and substantial public health impact by promoting quality and representativeness in clinical care, research, and policy. Our proposal is innovative because it includes novel applications of model variability constraints and metrics; it also includes multidisciplinary advisors to ensure person-centered model development and evaluation. This study is feasible because of our team’s expertise and our rich research and clinical environment—all critical to navigating the complex sociotechnical context in which the proposal exists.

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Acute Physiology and Chronic Health Evaluation

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National Heart  Lung  and Blood Institute

# data[].attributes.title
Enhancing responses to mRNA-lipid nanoparticle vaccines via utilization of endogenous lipid function

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
mRNA - lipid nanoparticle (LNP) vaccines developed against SARS-CoV-2 proved to be a transformative technology that saved millions of lives during the COVID-19 pandemic. In this vaccine platform, LNPs function as both a delivery agent and a powerful adjuvant, but the mechanisms contributing to LNP adjuvanticity are not fully understood, hindering future vaccine design. In this proposal I will investigate how selectively altering the lipids within an LNP impacts biodistribution and cell-specific protein translation from mRNA following intramuscular administration, and whether these alterations can promote stronger cellular and humoral adaptive immune responses. Phosphatidylserine (PS) is a negatively charged phospholipid normally present on the inner leaflet of a cell’s plasma membrane but can become exposed on the outer leaflet during apoptosis. When this occurs, PS is sensed by scavenger receptors of phagocytic antigen presenting cells (APCs), triggering phagocytosis. Globotriaosylceramide (Gb3) is a glycosphingolipid that promotes migration of germinal center B cells from the dark zone to the light zone by enhancing a B cell receptor (BCR) signaling cascade that results in a decrease of CXCR4 expression. By incorporating these endogenous lipids into LNP formulations, this proposal will test if they can direct cell and tissue-specific protein expression from mRNA-LNPs, and if they can impact humoral and cellular immune responses. In Aim 1 I will determine the cellular uptake pathway for these modified LNPs in vitro and their biodistribution in vivo. In Aim 2 I will elucidate how incorporation of PS and Gb3 lipids into LNPs impacts adaptive immune responses in vivo. Overall, I hypothesize that adaptive immune responses to mRNA-lipid nanoparticle vaccines can be specifically modulated based on incorporation of endogenous lipids into the LNP formulation. The ability to alter immune responses to mRNA-LNP vaccines by leveraging endogenous lipid function within an LNP would be hugely beneficial in creating more tailored, effective vaccines against both existing and emerging infectious pathogens.

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Structure of germinal center of lymph node

# data[].attributes.title
Elucidating the molecular determinants of novel anti-henipavirus antiviral compounds

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
Henipaviruses are recently emerged zoonotic viruses in the family Paramyxoviridae that can spill over from their pteropid bat reservoir into humans to cause severe respiratory disease with high mortality. There are no approved antivirals to treat infection by Hendra virus (HeV) and Nipah virus (NiV), the two henipaviruses that cause disease in humans, and identifying antivirals is challenging due to their classification as biosafety level 4 (BSL4) pathogens. We have assembled a library of 44,000 small molecules containing compounds with diverse structures, including 1,000 nucleoside analogs, and screened for antiviral activity against a recombinant, non-pathogenic henipavirus, Cedar virus, that expresses GFP (CedV-GFP). We screened in Calu-3 lung epithelial cells, which are permissive to respiratory virus infection and resemble primary cells in their morphology and signaling pathways. We identified 64 compounds that inhibit infection, including two lead compounds: CV-002 and UPGNUC255. Their antiviral activity was validated in diverse cellular models. CV-002 is a non-nucleoside compound with no previously described antiviral activity, so to start to determine the mechanism of action, we generated 5 CV-002-resistant strains of CedV-GFP (CV002Rs) by selection through serial passaging with increasing doses of CV-002. By sequencing the RNA genomes of the CV002Rs, we identified mutations in the L gene that encodes the RNA-dependent RNA polymerase (RdRp) of CedV-GFP. Modeling the locations of the residues changed in the CV002Rs showed that they are in close proximity to the active site of the RdRp (GDN). Thus, I hypothesize that CV-002 blocks viral replication at the viral RNA level by directly targeting the RdRp activity of Cedar virus. In contrast, UPGNUC255 is a nucleoside analog, a class of antivirals that typically targets the viral RdRp and acts through mutagenesis or (delayed) chain termination during RNA replication. However, the antiviral mechanism of action for UPGNUC255 is unknown and will be explored. Furthermore, the Cherry lab has shown that nucleoside analog antivirals can synergize with nucleoside biosynthesis inhibitors to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and rubella infections. Thus, I hypothesize that UPGNUC255 targets the Cedar virus RdRp for its antiviral activity and its activity can be improved through co-administration with at least one class of nucleoside biosynthesis inhibitors. In Aim 1, I will confirm the amino acid residues in Cedar virus L protein that are essential for CV-002 antiviral activity and use structure activity relationships (SAR) to optimize this activity. In Aim 2, I will generate UPGNUC255-resistant mutant strains of CedV-GFP and sequence their RNA genomes to determine UPGNUC255’s viral protein target. I will also co-administer UPGNUC255 with nucleoside biosynthesis inhibitors to determine if there is synergistic antiviral activity with these combinations. The proposed experiments will provide insight into the mechanisms of action of these newly identified antiviral compounds and may facilitate future development of antivirals against Hendra virus and Nipah virus.

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Phase 1 study of a SARS-CoV-2 vaccine adjuvanted via controlled biodistribution of mRNA encoding spike protein and IL-12p70

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
mRNA-lipid nanoparticle (LNP)-based vaccines are an exciting platform that made advances in combating the pandemic viruses. However, currently licensed mRNA-LNP vaccines approaches are limited in their ability to induce long lived antibody durability, degree of protection varies by age, and levels of cell mediated immunity (CMI) are suboptimal. mRNA vaccine self-adjuvantation is lower in aged individuals, with impaired immune activation upon exposure, inducing insufficient immunity with consequential impaired protection. To try to advance solutions, our published and unpublished work focus on two major novel mRNA vaccine innovations. One is a multi-organ protection (MOP) mRNA sequence homologous to tissue-specific micro-RNAs and enable tissue- specific mRNA translation, constraining expression to the site of injection. Secondly, a biological mRNA-encoded molecular adjuvant precisely guides immunity through inducing the potent and Th1-polarizing analyte, IL-12p70. Based on promising SARS-CoV-2 spike-trimer specific humoral and CMI, in young and aged murine models, and protection from viral challenge in non-human primates (NHPs), the goal of this U01 IICT application is to evaluate a mRNA encoding molecular adjuvant, delivered alongside MOP technology, in the context of a SARS-CoV-2 vaccine. Spike-MOP (CTx892) and IL-12-MOP (CTx672) are first-in-human evaluations, so to assess safety and tolerability, we would first perform dose escalations for CTx892 (stage 1A) and CTx 672 (stage 1B). Based on tolerability, doses less than maximal tolerated CTx892 are chosen to expand sample size for subsequent immunogenicity and mechanism studies. In stage 2, two different doses of CTx 892 will be paired with an escalating CTx672 (IL-12-MOP, e.g., 0.1, 1 µg) dose to assess adjuvanticity along with local and systemic safety and tolerability. Additionally, humoral immunity will be quantified with Spike-specific total IgG (titer and pre-immunization fold- change), IgG1 and IgG3 (Th1 markers), and IgG4 (Th2 marker), with surrogate virus, pseudo- virus, and true viral neutralization. Cellular immunity will include innate assessment in the days after, and adaptive CD4, CD8, and B cell immunity in the weeks, post-immunization. Further readouts include dried blood spots in the hours post-injection to assess proteomic kinetics. In Stage 3, biopsies of lymph node at ~14 days post-immunization and bone marrow at 6 months post-immunization will enable in-depth immunophenotyping and quantification of long-lived plasma cell (LLPC) responses. Durability of humoral and cellular immunity will be probed with a 6-month follow-up sampling of peripheral blood, IL-12-sustained humoral and cellular immunity.

# data[].attributes.title
SMAC Mimetics as Broad-Spectrum Antivirals

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
Antivirals that are currently in clinical use target a limited number of viruses or viral subgroups, have moderate efficacy and are prone to resistance. Current approaches for antiviral development mainly target viral proteins with enzymatic activity. A disadvantage of this approach, especially for RNA viruses, is that their small genomes offer few drug targets and high mutation rates lead to rapid emergence of drug-resistant strains. The discovery of potent, broad-spectrum antivirals with a high barrier to resistance therefore remains an urgent, unmet medical need for the treatment of endemic and emerging viral infections. Agents with these properties will most likely target host factors that are required for replication of multiple viruses and/or innate immune circuits that govern endogenous cellular defense mechanisms. SMAC mimetics, first developed to induce immunogenic death of tumor cells, are now emerging as such pan-antivirals. These agents simulate the activity of endogenous SMAC to block the action of inhibitor of apoptosis proteins (IAP). Although best known for their regulation of caspases during inflammation and cell death, IAPs also influence ubiquitin (Ub)-dependent signaling pathways that modulate innate immune responses. Several SMAC mimetics have already entered clinical trials for cancer treatment. As for antiviral therapy, research thus far has focused on SMAC mimetics for treatment of chronic viral infections, such as Hepatitis B virus and as latency reversal agents (LRAs) of HIV-1 infection. A recent report described the antiviral activity of a potent, monovalent SMAC mimetic against flaviviruses, SARS-CoV-2 and influenza A13. We have generated similar findings with SARS-CoV-2, Dengue 2 and influenza A using SMAC mimetics developed by our group. Owing to our current HIV-1 LRA program, we have novel compounds in hand that feature a range of activity profiles. We hypothesize that SMAC mimetics can be developed into potent pan- antivirals because they preferentially kill infected cells, which are sensitized to death due to activation of innate immune circuits. We recognize that SMAC mimetics may also affect cellular processes universally required for or inhibiting viral replication. This project will focus on RNA viruses with pandemic potential, including influenza A, flaviviruses (Dengue, Zika and West Nile), and SARS-CoV-2 variants. In Aim 1 we propose to investigate the breadth and potency of the antiviral activity of SMAC mimetics. Here, we will also delineate the stage of the viral replication cycle that is affected by SMAC mimetics and/or that triggers their antiviral properties. Aim 2 will rely on systems biology approaches to identify the host factors that are implicated in SMAC mimetic antiviral activity. Overall, the proposed studies will identify the mechanisms and pathways that are responsible for the antiviral activity of SMAC mimetics and enable their further optimization as broad-acting antivirals.

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Clustered Regularly Interspaced Short Palindromic Repeats

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
Among the estimated 10 million people with tuberculosis (TB) in 2022, over 3 million were not diagnosed, underscoring the need for new tools and diagnostic strategies to improve TB case detection, including in difficult to-diagnose populations such as children and people with extrapulmonary or early/subclinical TB. An equally urgent need is for drug susceptibility tests (DST) that can rapidly identify TB drug resistance/susceptibility, including to new drugs, to cure each person with TB and to protect the efficacy of newer drugs for those who may benefit from them in the future. Partially fueled by innovative platforms developed to address the COVID-19 epidemic, the last decade has seen a surge of new TB diagnostic platforms and assays. These new tests, sometimes developed by small companies with limited resources and little or no experience working with Mycobacterium tuberculosis (MTB) and clinical TB, require rigorous and unbiased evaluations. Furthermore, many diagnostic developers do not sufficiently appreciate the challenges presented by sample processing, the (often) need for high test sensitivity, or the acceptable tradeoffs between sensitivity/specific versus assay costs, ease of use and relevant target populations or TB disease states. Thus, the unmet needs of TB diagnostic developers are specific to the type of manufacturer, diagnostic technology, assay format, and intended use. Our proposal brings together a consortium of experienced investigators and a global network of clinical research sites to support TB diagnostic evaluations through a fast-paced and flexible pipeline that includes tech scouting, development mentoring, and clinical testing of early-stage TB diagnostics. With the inclusion of an Analytic Laboratory Core that can assess and help optimize new technologies prior to and after clinical studies our program offers a unique opportunity to accelerate promising TB diagnostics through their optimal development pipeline. Consortium members have almost three decades of leadership experience in diagnostic tech scouting, research, development, clinical trialing, and implementation activities. Fielding a balance of established platforms, fast followers, and cutting- edge technologies, we will perform the following specific aims: 1) identify promising early-stage diagnostics for evaluation and develop for each a stepwise evaluation plan; 2) evaluate the diagnostic accuracy of novel rapid point of care/near care TB diagnostics and determine the impact of relevant patient characteristics on test accuracy; and 3) provide feedback to diagnostic developers, policymakers, and other stakeholders on performance and usability of novel diagnostic tests and potential strategies for use in TB endemic settings.

# data[].attributes.keywords[]
United States National Institutes of Health

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
Among the estimated 10 million people with tuberculosis (TB) in 2022, over 3 million were not diagnosed, underscoring the need for new tools and diagnostic strategies to improve TB case detection, including in difficult to-diagnose populations such as children and people with extrapulmonary or early/subclinical TB. An equally urgent need is for drug susceptibility tests (DST) that can rapidly identify TB drug resistance/susceptibility, including to new drugs, to cure each person with TB and to protect the efficacy of newer drugs for those who may benefit from them in the future. Partially fueled by innovative platforms developed to address the COVID-19 epidemic, the last decade has seen a surge of new TB diagnostic platforms and assays. These new tests, sometimes developed by small companies with limited resources and little or no experience working with Mycobacterium tuberculosis (MTB) and clinical TB, require rigorous and unbiased evaluations. Furthermore, many diagnostic developers do not sufficiently appreciate the challenges presented by sample processing, the (often) need for high test sensitivity, or the acceptable tradeoffs between sensitivity/specific versus assay costs, ease of use and relevant target populations or TB disease states. Thus, the unmet needs of TB diagnostic developers are specific to the type of manufacturer, diagnostic technology, assay format, and intended use. Our proposal brings together a consortium of experienced investigators and a global network of clinical research sites to support TB diagnostic evaluations through a fast-paced and flexible pipeline that includes tech scouting, development mentoring, and clinical testing of early-stage TB diagnostics. With the inclusion of an Analytic Laboratory Core that can assess and help optimize new technologies prior to and after clinical studies our program offers a unique opportunity to accelerate promising TB diagnostics through their optimal development pipeline. Consortium members have almost three decades of leadership experience in diagnostic tech scouting, research, development, clinical trialing, and implementation activities. Fielding a balance of established platforms, fast followers, and cutting- edge technologies, we will perform the following specific aims: 1) identify promising early-stage diagnostics for evaluation and develop for each a stepwise evaluation plan; 2) evaluate the diagnostic accuracy of novel rapid point of care/near care TB diagnostics and determine the impact of relevant patient characteristics on test accuracy; and 3) provide feedback to diagnostic developers, policymakers, and other stakeholders on performance and usability of novel diagnostic tests and potential strategies for use in TB endemic settings.

# data[].attributes.keywords[]
United States National Institutes of Health

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
Among the estimated 10 million people with tuberculosis (TB) in 2022, over 3 million were not diagnosed, underscoring the need for new tools and diagnostic strategies to improve TB case detection, including in difficult to-diagnose populations such as children and people with extrapulmonary or early/subclinical TB. An equally urgent need is for drug susceptibility tests (DST) that can rapidly identify TB drug resistance/susceptibility, including to new drugs, to cure each person with TB and to protect the efficacy of newer drugs for those who may benefit from them in the future. Partially fueled by innovative platforms developed to address the COVID-19 epidemic, the last decade has seen a surge of new TB diagnostic platforms and assays. These new tests, sometimes developed by small companies with limited resources and little or no experience working with Mycobacterium tuberculosis (MTB) and clinical TB, require rigorous and unbiased evaluations. Furthermore, many diagnostic developers do not sufficiently appreciate the challenges presented by sample processing, the (often) need for high test sensitivity, or the acceptable tradeoffs between sensitivity/specific versus assay costs, ease of use and relevant target populations or TB disease states. Thus, the unmet needs of TB diagnostic developers are specific to the type of manufacturer, diagnostic technology, assay format, and intended use. Our proposal brings together a consortium of experienced investigators and a global network of clinical research sites to support TB diagnostic evaluations through a fast-paced and flexible pipeline that includes tech scouting, development mentoring, and clinical testing of early-stage TB diagnostics. With the inclusion of an Analytic Laboratory Core that can assess and help optimize new technologies prior to and after clinical studies our program offers a unique opportunity to accelerate promising TB diagnostics through their optimal development pipeline. Consortium members have almost three decades of leadership experience in diagnostic tech scouting, research, development, clinical trialing, and implementation activities. Fielding a balance of established platforms, fast followers, and cutting- edge technologies, we will perform the following specific aims: 1) identify promising early-stage diagnostics for evaluation and develop for each a stepwise evaluation plan; 2) evaluate the diagnostic accuracy of novel rapid point of care/near care TB diagnostics and determine the impact of relevant patient characteristics on test accuracy; and 3) provide feedback to diagnostic developers, policymakers, and other stakeholders on performance and usability of novel diagnostic tests and potential strategies for use in TB endemic settings.

# data[].attributes.keywords[]
United States National Institutes of Health

# data[].attributes.title
MAC formation and Cell-Specific Inflammasome Activation in COVID-19

# data[].attributes.funder_divisions[]
National Institute of Allergy and Infectious Diseases (NIAID)

# data[].attributes.abstract
Program summary: The objective of this training proposal is to determine how enhanced complement activation and increased membrane attack complex (MAC) formation exacerbate severe COVID-19. The complement system, a key component of the innate immunity, can be initiated by three pathways (lectin, alternative, and classical), potentially leading to MAC formation. MAC's primary function is to lyse pathogens via pore formation. However, clinical evidence indicates that complement activation and MAC formation, while normally protective, can be detrimental in SARS-CoV-2 infection and contribute to COVID-19 pathogenesis. Currently, the cellular and molecular mechanisms underlying MAC-accelerated severe COVID-19 remain unexplored. To address this question, we have characterized a murine model of severe COVID-19 using a mouse-adapted strain (MA30) that recapitulates key aspects of SARS-CoV2 infection, including lung edema and epithelial cell tropism. Using this MA30 strain to infect an array of complement deficient mice (C3-/- and C7-/-) and mice deficient in the critical MAC regulator CD59 (mCd59-/-), I demonstrated a causative role of MAC on severe COVID-19. However, the cell targets and molecular mechanism of MAC-mediated severe COVID-19 remain unknown. Our preliminary data show increased activity of Caspase-1, a downstream event of NLRP3 inflammasome formation, in LPS- challenged mCD59-/- mice. Additionally, NLRP3 inflammasome formation and Caspase-1 activation, leading to the release of IL-1β and IL-18, contributes to the cytokine storm and severe immunopathology in COVID-19. Our single-cell and bulk RNA sequencing data show increased transcription of the casp-1, IL-18 and Gsdmd in endothelial cells and macrophages of MA30 infected mice at 2 days-post infection. Therefore, my overarching hypothesis is that MAC targets endothelial cells and macrophages, accelerating severe COVID-19 through the activation of Caspase-1 pathway. To test this central hypothesis, I propose the following aims. Aim 1 is to determine the pathogenic role of MAC-mediated Casp1 activation in severe COVID-19. Aim 2 is to determine the MAC-mediated cellular effects on COVID-19 and associate the disease severity with cell specific casp1 activation. With our prior work we established a causative role for MAC in severe COVID-19 pathogenesis. This proposal advances that work by determining the cellular and molecular mechanisms by which MAC causes severe COVID-19. By elucidating the role of the MAC/Casp1 axis in specific cell types during severe COVID-19, this research will further our understanding of the disease's immunopathology, and better prepare us for new SARS variants and emerging diseases. A better understanding is crucially needed to identify novel therapeutic targets for mitigating cytokine storm and improving outcomes for critically ill patients.