Journal Article

N-GSDMD trafficking to neutrophil organelles facilitates IL-1β release independently of plasma membrane pores and pyroptosis

Karmakar, Mausita, Catz, Sergio D., Minns, Martin, Diaz-Aponte, Jose, Wang, Kun, Greenberg, Elyse N., Pearlman, Eric, Dubyak, George R., Rathkey, Joseph K., Shao, Feng, Abbott, Derek W., Pestonjamasp, Kersi, Johnson, Jennifer L.

2020

Overview

Gasdermin-D (GSDMD) in inflammasome-activated macrophages is cleaved by caspase-1 to generate N-GSDMD fragments. N-GSDMD then oligomerizes in the plasma membrane (PM) to form pores that increase membrane permeability, leading to pyroptosis and IL-1β release. In contrast, we report that although N-GSDMD is required for IL-1β secretion in NLRP3-activated human and murine neutrophils, N-GSDMD does not localize to the PM or increase PM permeability or pyroptosis. Instead, biochemical and microscopy studies reveal that N-GSDMD in neutrophils predominantly associates with azurophilic granules and LC3 + autophagosomes. N-GSDMD trafficking to azurophilic granules causes leakage of neutrophil elastase into the cytosol, resulting in secondary cleavage of GSDMD to an alternatively cleaved N-GSDMD product. Genetic analyses using ATG7-deficient cells indicate that neutrophils secrete IL-1β via an autophagy-dependent mechanism. These findings reveal fundamental differences in GSDMD trafficking between neutrophils and macrophages that underlie neutrophil-specific functions during inflammasome activation. In macrophages, IL-1β secretion is mediated by N-GSDMD pores in the plasma membrane (PM). Here the authors show that in neutrophils, IL-1β secretion occurs in the absence of PM pores, via autophagosomes; N-GSDMD does not traffic to PM but to azurophilic granules, thereby releasing neutrophil elastase which cleaves further N-GSDMD into alternative fragments.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 13/1 / 13/106 / 13/21 / 13/95 / 14/19 / 14/69 / 631/250/127/1213 / 631/250/1932 / 631/250/2504/223/1699 / 631/250/256/2177 / 631/80/82/39 / Animals / Autophagosomes - metabolism / Autophagy / Autophagy - genetics / Caspase 1 - metabolism / Caspase-1 / Cell activation / Cell Membrane - metabolism / Cell Membrane Permeability - genetics / Cytosol / Elastase / Fragments / Genetic analysis / Granular materials / Humanities and Social Sciences / Humans / IL-1β / Inflammasomes / Inflammasomes - metabolism / Interleukin-1beta - metabolism / Intracellular Signaling Peptides and Proteins - genetics / Intracellular Signaling Peptides and Proteins - metabolism / Leukocyte Elastase - genetics / Leukocyte Elastase - metabolism / Leukocytes (neutrophilic) / Macrophages / Macrophages - metabolism / Membrane permeability / Membranes / Mice, Inbred C57BL / Mice, Knockout / multidisciplinary / Neutrophils / Neutrophils - metabolism / Oligomerization / Organelles / Organelles - metabolism / Permeability / Phagocytosis / Phagosomes / Phosphate-Binding Proteins - genetics / Phosphate-Binding Proteins - metabolism / Pores / Porosity / Protein Transport / Pyroptosis / Pyroptosis - genetics / Science / Science (multidisciplinary)