Institute for Hygiene, University of Münster, Münster, Germany.
Thromb Haemost. 2011 Mar;105(3):515-28. doi: 10.1160/TH10-02-0140. Epub 2010 Dec 6.
Shiga toxin (Stx)-mediated injury to vascular endothelial cells in the kidneys, brain and other organs underlies the pathogenesis of haemolytic uraemic syndrome (HUS) caused by enterohaemorrhagic Escherichia coli (EHEC). We present a direct and comprehensive comparison of cellular injury induced by the two major Stx types, Stx1 and Stx2, in human brain microvascular endothelial cells (HBMECs) and EA.hy 926 macrovascular endothelial cells. Scanning electron microscopy of microcarrier-based cell cultures, digital holographic microscopy of living single cells, and quantitative apoptosis/necrosis assays demonstrate that Stx1 causes both necrosis and apoptosis, whereas Stx2 induces almost exclusively apoptosis in both cell lines. Moreover, microvascular and macrovascular endothelial cells have different susceptibilities to the toxins: EA.hy 926 cells are slightly, but significantly (∼ 10 times) more susceptible to Stx1, whereas HBMECs are strikingly (≥ 1,000 times) more susceptible to Stx2. These findings have implications in the pathogenesis of HUS, and suggest the existence of yet to be delineated Stx type-specific mechanisms of endothelial cell injury beyond inhibition of protein biosynthesis.
志贺毒素（Stx）介导的肾脏、大脑和其他器官血管内皮细胞损伤是肠出血性大肠杆菌（EHEC）引起的溶血性尿毒综合征（HUS）的发病机制。我们对两种主要的 Stx 型（Stx1 和 Stx2）在人脑血管内皮细胞（HBMEC）和 EA.hy 926 大血管内皮细胞中诱导的细胞损伤进行了直接和全面的比较。基于微载体的细胞培养物的扫描电子显微镜、活单细胞的数字全息显微镜和定量细胞凋亡/坏死检测表明，Stx1 可引起坏死和凋亡，而 Stx2 几乎仅在两种细胞系中诱导凋亡。此外，微血管和大血管内皮细胞对毒素的敏感性不同：EA.hy 926 细胞对 Stx1 的敏感性略高，但差异有统计学意义（约 10 倍），而 HBMEC 对 Stx2 的敏感性显著更高（≥1000 倍）。这些发现对 HUS 的发病机制有影响，并表明除了抑制蛋白质生物合成之外，还存在尚未明确的 Stx 型特异性内皮细胞损伤机制。
