Interleukin-33 (IL-33) is a member of the IL-1 cytokine family and plays critical roles in facilitating type-2 immune responses. IL-33 is localized in the nucleus and released to the extracellular milieu during cell death, although the precise mechanisms underlying IL-33 mobilization remain unclear. Here, we found that nigericin, a toxin derived from Streptomyces hygroscopicus, promoted IL-33 translocation from the nucleus to the cytosol before extracellular release. This translocation was inhibited by chelating Ca²⁺ with EGTA or membrane protection by glycine treatment. Ca²⁺ ionophore A23187 stimulation caused IL-33 translocation to the cytoplasm but was not sufficient for extracellular release. However, IL-33 release was induced by detergent treatment, which indicates that membrane rupture is required for IL-33 release. The pore-forming pyroptosis executor gasdermin D was cleaved following nigericin stimulation, and overexpression of the cleaved gasdermin D-N-terminal fragment that forms the membrane pore sufficiently induced IL-33 release, which was blocked by EGTA and glycine. Together, these findings suggest that Ca²⁺-dependent signals and gasdermin D pore formation are required for robust IL-33 production.

白介素33（IL-33）是IL-1细胞因子家族的成员，在促进2型免疫应答中起关键作用。IL-33位于细胞核中，并在细胞死亡期间释放到细胞外环境中，尽管目前尚不清楚IL-33动员的确切机制。在这里，我们发现尼日灵是一种从吸水链霉菌衍生的毒素，在细胞外释放之前促进了IL-33从细胞核到胞质溶胶的转运。通过与EGTA螯合Ca ²⁺或通过甘氨酸处理保护膜来抑制这种移位。钙²⁺离子载体A23187刺激导致IL-33易位至细胞质，但不足以释放细胞外。但是，IL-33的释放是通过去污剂处理诱导的，这表明IL-33的释放需要膜破裂。在尼日利亚菌素刺激后裂解成孔的促凋亡执行者加德敏D，并且裂解的加德敏DN-末端片段的过表达形成膜孔，该片段充分诱导IL-33释放，其被EGTA和甘氨酸阻断。在一起，这些发现表明，Ca ²⁺依赖性信号和胃泌素D孔的形成对于鲁棒的IL-33产生是必需的。