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

M Karmakar, M Minns, EN Greenberg… - Nature …, 2020 - nature.com
M Karmakar, M Minns, EN Greenberg, J Diaz-Aponte, K Pestonjamasp, JL Johnson…
Nature communications, 2020nature.com
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 …
Abstract
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.
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