Lyososome Membrane Permeabilization Induces Plasma Membrane Macropores to Activate K +-Efflux-Dependent NLRP3 Inflammasomes in Murine Dendritic Cells

Abstract NLRP3 is a cytosolic sensor protein in myeloid leukocytes that recruits the adaptor ASC and activates caspase-1 functional inflammasomes. Caspase-1 coordinately cleaves pro-IL-1β to bioactive IL-1β gasdermin D (GSDMD) induce N-GSDMD macropores plasma membrane (PM). The latter mediate efflux of mature initiate progression pyroptosis, lytic cell death. activation triggered by perturbed cellular homeostasis with decreased [K +] being best-characterized signal. required K +efflux typically induced ionophore nigericin or extracellular ATP as an agonist for P2X7 receptor channels. +efflux-dependent also soluble particulate agents which accumulate lysosomes lysosomal permeabilization (LMP) release hydrolytic enzymes into cytosol; particulates include alum widely used vaccine adjuvant. mechanisms LMP rapidly triggers changes permeability remain undefined. We model murine bone marrow derived dendritic cells (BMDC) treated agent Leu-Leu-O-methyl ester (LLME) elicit K+ activation. Notably, this was coincident influx propidiumiodide (PI), 668 Da organic salt routinely track assembly such GSDMD. Equivalent LLME-induced PI observed wildtype Gsdmd−/−BMDC unaffected inhibition caspase-1. These observations indicate rapid endogenous pore-forming distinct from Current studies are evaluating E pannexin-1 candidates. Supported grants NIH (P01-AI141350 R01-EY014362)