Disrupted mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) generation are often associated with macrophage pyroptosis. It remains unclear how these forms of mitochondrial dysfunction relate to inflammasome activation and gasdermin-D (Gsdmd) cleavage, two central steps of the pyroptotic process. Here, we also found MMP collapse and ROS generation induced by Nlrp3 inflammasome activation as previous studies reported. The elimination of ROS alleviated the cleavage of Gsdmd, suggesting that Gsdmd cleavage occurs downstream of ROS release. Consistent with this result, hydrogen peroxide treatment augmented the cleavage of Gsdmd by caspase-1. Indeed, four amino acid residues of Gsdmd were oxidized under oxidative stress in macrophages. The efficiency of Gsdmd cleavage by inflammatory caspase-1 was dramatically reduced when oxidative modification was blocked by mutation of these amino acid residues. These results demonstrate that Gsdmd oxidation serves as a de novo mechanism by which mitochondrial ROS promote Nlrp3 inflammasome-dependent pyroptotic cell death.

中文翻译：

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线粒体ROS通过诱导GSDMD氧化来促进巨噬细胞凋亡。

线粒体膜电位（MMP）的破坏和活性氧（ROS）的产生通常与巨噬细胞凋亡有关。尚不清楚这些形式的线粒体功能障碍与炎性体激活和胃泌素-D（Gsdmd）裂解（焦磷酸化过程的两个主要步骤）之间的关系。在这里，我们还发现Nlrp3炎性小体激活引起的MMP崩溃和ROS生成，如先前的研究报道。ROS的消除减轻了Gsdmd的裂解，表明Gsdmd的裂解发生在ROS释放的下游。与此结果一致，过氧化氢处理增加了caspase-1对Gsdmd的切割。实际上，在巨噬细胞中的氧化应激下，Gsdmd的四个氨基酸残基被氧化。当氧化修饰被这些氨基酸残基的突变所阻断时，发炎的胱天蛋白酶-1切割Gsdmd的效率大大降低。这些结果表明，Gsdmd氧化起着从头机制，线粒体ROS通过该机制促进Nlrp3炎性体依赖性烧伤细胞的死亡。