Shiga toxins (Stxs) produced by Stx‐producing Escherichia coli are the primarily virulence factors of hemolytic uremic syndrome and central nervous system (CNS) impairment. Although the precise mechanisms of toxin dissemination remain unclear, Stxs bind to extracellular vesicles (EVs). Exosomes, a subset of EVs, may play a key role in Stx‐mediated renal injury. To test this hypothesis, we isolated exosomes from monocyte‐derived macrophages in the presence of Stx2a or Stx2 toxoids. Macrophage‐like differentiated THP‐1 cells treated with Stxs secreted Stx‐associated exosomes (Stx‐Exo) of 90–130 nm in diameter, which induced cytotoxicity in recipient cells in a toxin receptor globotriaosylceramide (Gb₃)‐dependent manner. Stx2‐Exo engulfed by Gb₃‐positive cells were translocated to the endoplasmic reticulum in the human proximal tubule epithelial cell line HK‐2. Stx2‐Exo contained pro‐inflammatory cytokine mRNAs and proteins and induced more severe inflammation than purified Stx2a accompanied by greater death of target cells such as human renal or retinal pigment epithelial cells. Blockade of exosome biogenesis using the pharmacological inhibitor GW4869 reduced Stx2‐Exo‐mediated human renal cell death. Stx2‐Exo isolated from human primary monocyte–derived macrophages activated caspase 3/7 and resulted in significant cell death in primary human renal cortical epithelial cells. Based on these results, we speculate that Stx‐containing exosomes derived from macrophages may exacerbate cytotoxicity and inflammation and trigger cell death in toxin‐sensitive cells. Therapeutic interventions targeting Stx‐containing exosomes may prevent or ameliorate Stx‐mediated acute vascular dysfunction.

中文翻译：

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从志贺毒素 2a 处理的人类巨噬细胞释放的外泌体调节炎症反应并诱导表达毒素受体的人类细胞的细胞死亡。

产 Stx 的大肠杆菌产生的志贺毒素 (Stxs)是溶血性尿毒症综合征和中枢神经系统 (CNS) 损伤的主要毒力因子。虽然毒素传播的确切机制尚不清楚，但 Stxs 与细胞外囊泡 (EVs) 结合。外泌体是 EV 的一个子集，可能在 Stx 介导的肾损伤中起关键作用。为了验证这一假设，我们在 Stx2a 或 Stx2 类毒素存在的情况下从单核细胞衍生的巨噬细胞中分离出外泌体。用 Stxs 处理的巨噬细胞样分化 THP-1 细胞分泌直径 90-130 nm 的 Stx 相关外泌体（Stx-Exo），以毒素受体球三酰神经酰胺（Gb ₃）依赖性方式诱导受体细胞的细胞毒性。Stx2-Exo 被 Gb ₃吞没阳性细胞被转移到人近曲小管上皮细胞系 HK-2 中的内质网。Stx2-Exo 含有促炎细胞因子 mRNA 和蛋白质，比纯化的 Stx2a 诱导更严重的炎症，伴随着更多的靶细胞（如人肾或视网膜色素上皮细胞）死亡。使用药理学抑制剂 GW4869 阻断外泌体生物发生减少了 Stx2-Exo 介导的人类肾细胞死亡。从人原代单核细胞衍生的巨噬细胞中分离的 Stx2-Exo 可激活 caspase 3/7，并导致原代人肾皮质上皮细胞中的显着细胞死亡。基于这些结果，我们推测源自巨噬细胞的含有 Stx 的外泌体可能会加剧细胞毒性和炎症，并引发毒素敏感细胞的细胞死亡。