N-GSDMD trafficking to neutrophil organelles facilitates IL-1β release independently of plasma membrane pores and pyroptosis
N-GSDMD trafficking to neutrophil organelles facilitates IL-1β release independently of plasma membrane pores and pyroptosis
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DOI：
10.1038/s41467-020-16043-9
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发表时间：
2020-05-05
影响因子：
16.6
通讯作者：
Pearlman, Eric
中科院分区：
文献类型：
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作者：
Karmakar, Mausita;Minns, Martin;Pearlman, Eric
炎性小体激活的巨噬细胞中的Gasdermin-D （GSDMD）被caspase-1切割生成N-GSDMD片段。然后N-GSDMD在质膜（PM）中寡聚形成孔隙，增加膜通透性，导致焦亡和IL-1 β释放。相反，我们报道，尽管nlrp3激活的人和小鼠中性粒细胞分泌IL-1 β需要N-GSDMD，但N-GSDMD并不定位于PM或增加PM的通透性或焦亡。相反，生化和显微镜研究显示中性粒细胞中的N-GSDMD主要与嗜氮颗粒和LC3（+）自噬体相关。N-GSDMD运输到亲氮颗粒会导致中性粒细胞弹性酶渗漏到细胞质中，导致GSDMD的二次裂解为选择性裂解的N-GSDMD产物。利用atg7缺陷细胞的遗传分析表明，中性粒细胞通过自噬依赖机制分泌IL-1 β。这些发现揭示了中性粒细胞和巨噬细胞之间GSDMD运输的根本差异，这是炎症小体激活过程中中性粒细胞特异性功能的基础。在巨噬细胞中，IL-1 β的分泌是由质膜（PM）上的N-GSDMD孔介导的。在这里，作者表明，在中性粒细胞中，IL-1 β分泌发生在没有PM孔的情况下，通过自噬体；N-GSDMD不会进入PM，而是进入亲氮颗粒，从而释放中性粒细胞弹性酶，将N-GSDMD进一步裂解成其他片段。
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-1 beta release. In contrast, we report that although N-GSDMD is required for IL-1 beta 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-1 beta 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-1 beta secretion is mediated by N-GSDMD pores in the plasma membrane (PM). Here the authors show that in neutrophils, IL-1 beta 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.