Ghorashi Atossa C, Boucher Andrew, Archer-Hartmann Stephanie A, Murray Nathan B, Konada Rohit Sai Reddy, Zhang Xunzhi, Xing Chao, Azadi Parastoo, Yrlid Ulf, Kohler Jennifer J
Department of Biochemistry, UT Southwestern Medical Center, Dallas TX 75390 USA.
Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, 405 30 Gothenburg, Sweden.
bioRxiv. 2023 Aug 3:2023.08.02.551727. doi: 10.1101/2023.08.02.551727.
Cholera toxin (CT) is the etiological agent of cholera. Here we report that multiple classes of fucosylated glycoconjugates function in CT binding and intoxication of intestinal epithelial cells. In Colo205 cells, knockout of B3GNT5, the enzyme required for synthesis of lacto- and neolacto-series glycosphingolipids (GSLs), reduces CT binding but sensitizes cells to intoxication. Overexpressing B3GNT5 to generate more fucosylated GSLs confers protection against intoxication, indicating that fucosylated GSLs act as decoy receptors for CT. Knockout (KO) of B3GALT5 causes increased production of fucosylated O-linked and N-linked glycoproteins, and leads to increased CT binding and intoxication. Knockout of B3GNT5 in B3GALT5 KO cells eliminates production of fucosylated GSLs but increases intoxication, identifying fucosylated glycoproteins as functional receptors for CT. These findings provide insight into molecular determinants regulating CT sensitivity of host cells.
霍乱毒素（CT）是霍乱的病原体。在此我们报告，多种岩藻糖基化糖缀合物在CT与肠上皮细胞的结合及中毒过程中发挥作用。在Colo205细胞中，敲除合成乳糖系列和新乳糖系列糖鞘脂（GSLs）所需的酶B3GNT5，会减少CT结合，但使细胞对中毒更敏感。过表达B3GNT5以产生更多岩藻糖基化GSLs可提供抗中毒保护，表明岩藻糖基化GSLs作为CT的诱饵受体发挥作用。敲除B3GALT5会导致岩藻糖基化O-连接和N-连接糖蛋白的产生增加，并导致CT结合和中毒增加。在B3GALT5基因敲除细胞中敲除B3GNT5可消除岩藻糖基化GSLs的产生，但增加中毒，这表明岩藻糖基化糖蛋白是CT的功能性受体。这些发现为调节宿主细胞CT敏感性的分子决定因素提供了见解。
