Institute of Hygiene, University of Münster, D-48149 Münster, Germany.
Institute of Food Chemistry, University of Münster, D-48149 Münster, Germany.
Toxins (Basel). 2021 Feb 12;13(2):139. doi: 10.3390/toxins13020139.
Human kidney epithelial cells are supposed to be directly involved in the pathogenesis of the hemolytic-uremic syndrome (HUS) caused by Shiga toxin (Stx)-producing enterohemorrhagic (EHEC). The characterization of the major and minor Stx-binding glycosphingolipids (GSLs) globotriaosylceramide (Gb3Cer) and globotetraosylceramide (Gb4Cer), respectively, of primary human renal cortical epithelial cells (pHRCEpiCs) revealed GSLs with Cer (d18:1, C16:0), Cer (d18:1, C22:0), and Cer (d18:1, C24:1/C24:0) as the dominant lipoforms. Using detergent-resistant membranes (DRMs) and non-DRMs, Gb3Cer and Gb4Cer prevailed in the DRM fractions, suggesting their association with microdomains in the liquid-ordered membrane phase. A preference of Gb3Cer and Gb4Cer endowed with C24:0 fatty acid accompanied by minor monounsaturated C24:1-harboring counterparts was observed in DRMs, whereas the C24:1 fatty acid increased in relation to the saturated equivalents in non-DRMs. A shift of the dominant phospholipid phosphatidylcholine with saturated fatty acids in the DRM to unsaturated species in the non-DRM fractions correlated with the GSL distribution. Cytotoxicity assays gave a moderate susceptibility of pHRCEpiCs to the Stx1a and Stx2a subtypes when compared to highly sensitive Vero-B4 cells. The results indicate that presence of Stx-binding GSLs per se and preferred occurrence in microdomains do not necessarily lead to a high cellular susceptibility towards Stx.
人肾上皮细胞被认为直接参与由产志贺毒素（Stx）的肠出血性大肠杆菌（EHEC）引起的溶血性尿毒综合征（HUS）的发病机制。原代人肾皮质上皮细胞（pHRCEpiCs）中主要和次要 Stx 结合糖鞘脂（GSL）神经节三己糖神经酰胺（Gb3Cer）和神经节四己糖神经酰胺（Gb4Cer）的特征分别为 Cer（d18:1，C16:0）、Cer（d18:1，C22:0）和 Cer（d18:1，C24:1/C24:0）作为主要的脂类形式。使用去污剂抗性膜（DRM）和非 DRM，Gb3Cer 和 Gb4Cer 优先存在于 DRM 部分，表明它们与液态有序膜相中的微区相关联。观察到 DRMs 中具有 C24:0 脂肪酸的 Gb3Cer 和 Gb4Cer 以及具有少量单不饱和 C24:1-的对应物的偏爱，而 C24:1 脂肪酸与非 DRM 中的饱和当量增加有关。DRM 中具有饱和脂肪酸的主要磷脂酰胆碱向非 DRM 部分中不饱和物质的转移与 GSL 分布相关。与高度敏感的 Vero-B4 细胞相比，pHRCEpiCs 对 Stx1a 和 Stx2a 亚型的细胞毒性测定表现出中等的敏感性。结果表明，Stx 结合 GSL 的存在本身以及在微区中的优先出现并不一定导致细胞对 Stx 的高敏感性。
