Anti-inflammatory activity of hydrogels designed to capture extracellular inflammasomes

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PROJECT SUMMARY/ABSTRACT Multiprotein complexes known as inflammasomes form in innate immune cells to trigger inflammation upon detection of pathogens or tissue damage. Abnormal inflammasome activation leads to chronic inflammation, which is the culprit of numerous life-threatening diseases such as cancer, diabetes, cardiovascular disorders, and the cytokine storm in SARS-CoV-2 infection. Inflammasome assembly is controlled by protein-protein interactions as it requires the self-association and oligomerization of multiple copies of three proteins: sensors to detect danger signals, a protease to activate inflammatory factors, and the adaptor protein ASC to connect sensor and protease. Inflammasome formation leads to plasma membrane rupture and concomitant cell death, thus resulting in the release of proinflammatory cytokines and inflammasome particles to the extracellular environment. These extracellular inflammasomes are internalized by nearby cells to perpetuate and amplify the inflammatory response. Removing or sequestering extracellular inflammasomes will likely inhibit or reduce inflammation. Therefore, extracellular inflammasomes are potential therapeutic targets. Our laboratory’s extensive experience on the function and structure of the adaptor ASC, and its interactions with other inflammasome proteins, has led us to create hydrogels designed to form specific protein-protein interactions with inflammasomes; thus, they have the potential to broadly inhibit inflammation by effectively capturing and removing extracellular inflammasomes. This project focuses on identifying the hydrogelation factors leading to optimum biding of inflammasome particles in cell-free systems (Aim 1); and determining the anti-inflammatory efficiency of the hydrogels in the presence of activated innate immune cells (Aim 2). Our experimental plan will combine cell biology and biochemical approaches, including live/dead cell imaging, flow cytometry, immunoblotting, enzyme-linked immunosorbent assays and fluorescence spectroscopy. Overall, we expect to develop a hydrogel technology of broad applicability to reduce inflammation in the absence of drug loading by targeting the inflammasome, which is implicated in many inflammatory diseases.