GM1 ganglioside-independent intoxication by Cholera toxin.
GM1 ganglioside-independent intoxication by Cholera toxin.
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DOI：
10.1371/journal.ppat.1006862
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发表时间：
2018-03
期刊：
影响因子：
6.7
通讯作者：
Yrlid U
中科院分区：
文献类型：
--
作者：
Cervin J;Wands AM;Casselbrant A;Wu H;Krishnamurthy S;Cvjetkovic A;Estelius J;Dedic B;Sethi A;Wallom KL;Riise R;Bäckström M;Wallenius V;Platt FM;Lebens M;Teneberg S;Fändriks L;Kohler JJ;Yrlid U
霍乱毒素(CT)通过其B亚单位(CTB)与细胞表面受体结合后进入宿主细胞并中毒。我们最近已经证明，除了先前描述的结合伙伴神经节苷脂GM1外，CTB还与岩藻糖化蛋白结合。利用原代人类空肠上皮细胞和粒细胞的流式细胞术分析，我们现在发现CTB结合与岩藻糖化Lewis X(Lex)多糖的表达相关。这种结合被岩藻糖化的寡糖和岩藻糖结合的凝集素竞争性地阻断。CTB在体外结合Lex葡聚糖，当该部分与蛋白质连接而不与神经酰胺连接时，这种结合可被Lex的mAb阻断。抑制GM1缺陷的C6大鼠胶质瘤细胞的鞘糖脂合成或唾液酸化会导致对CT介导的中毒的敏化。最后，CT灌胃在缺乏GM1的基因敲除小鼠中产生完整的腹泻反应，即使在额外减少糖鞘脂后也是如此。因此，我们的结果表明，CT可以在没有GM1的情况下诱导毒性，并支持宿主糖蛋白在CT中毒中的作用。这些发现为阻断CT作用的治疗和设计解毒的肠毒素佐剂开辟了新的途径。霍乱是由霍乱弧菌产生的霍乱毒素引起的，每年造成10万人以上的死亡。当这种毒素被肠道细胞摄取时，会导致腹泻，而神经节苷脂GM1(一种糖脂)长期以来一直被认为是霍乱毒素的主要受体。我们在这里提供的数据显示，霍乱毒素与三糖血型抗原Lewis X中的岩藻糖结合。Lewis X在人粒细胞和肠道细胞上表达，并与霍乱毒素结合相关。此外，缺乏GM1表达的细胞系和缺乏GM1的小鼠接受进一步减少糖脂合成的治疗会受到霍乱毒素的毒害。这表明了糖蛋白的积极作用，因此我们的结果为霍乱毒素如何内化到人类肠道的细胞中提供了新的见解。这一知识可用于设计新型霍乱毒素候选药物抑制剂。另一种利用我们的发现的方法是将霍乱毒素修改为毒性较低的，以便它可以用作疫苗的佐剂。
Cholera toxin (CT) enters and intoxicates host cells after binding cell surface receptors via its B subunit (CTB). We have recently shown that in addition to the previously described binding partner ganglioside GM1, CTB binds to fucosylated proteins. Using flow cytometric analysis of primary human jejunal epithelial cells and granulocytes, we now show that CTB binding correlates with expression of the fucosylated Lewis X (LeX) glycan. This binding is competitively blocked by fucosylated oligosaccharides and fucose-binding lectins. CTB binds the LeX glycan in vitro when this moiety is linked to proteins but not to ceramides, and this binding can be blocked by mAb to LeX. Inhibition of glycosphingolipid synthesis or sialylation in GM1-deficient C6 rat glioma cells results in sensitization to CT-mediated intoxication. Finally, CT gavage produces an intact diarrheal response in knockout mice lacking GM1 even after additional reduction of glycosphingolipids. Hence our results show that CT can induce toxicity in the absence of GM1 and support a role for host glycoproteins in CT intoxication. These findings open up new avenues for therapies to block CT action and for design of detoxified enterotoxin-based adjuvants. The disease cholera, caused by cholera toxin produced by Vibrio cholerae, is responsible for over 100 000 deaths every year. When taken up by cells in the intestine, the toxin causes diarrhea, and the ganglioside GM1 (a glycolipid) has long been considered the main receptor for cholera toxin. We here present data showing that cholera toxin binds to fucose within the trisaccharide blood group antigen Lewis X. Lewis X is expressed on human granulocytes as well as intestinal cells and correlates with cholera toxin binding. Furthermore, cell lines deficient in GM1 expression and mice lacking GM1 treated to further reduce glycolipid synthesis are intoxicated by cholera toxin. This indicates an active role of glycoproteins, and our results thereby provide new insights on how cholera toxin is internalized into cells in the human intestine. This knowledge can be used to design novel drug candidate inhibitors of cholera toxin. Another way to utilize our findings is to modify cholera toxin to be less toxic so that it can be used as an adjuvant in vaccines.
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影响因子：
15.9
作者：
CARPENTER, CC;SACK, RB;STEENBERG, RW
通讯作者：
STEENBERG, RW
影响因子：
4.3
作者：
Breimer, Michael E.;Hansson, Gunnar C.;Leffler, Hakon
通讯作者：
Leffler, Hakon
影响因子：
4.3
作者：
El-Hawiet, Amr;Kitova, Elena N.;Klassen, John S.
通讯作者：
Klassen, John S.
影响因子：
6.7
作者：
Heggelund JE;Burschowsky D;Bjørnestad VA;Hodnik V;Anderluh G;Krengel U
通讯作者：
Krengel U
影响因子：
1.9
作者：
Bjorkman, Eleonora;Casselbrant, Anna;Fandriks, Lars
通讯作者：
Fandriks, Lars