The Myelin and Lymphocyte Protein MAL Is Required for Binding and Activity of Clostridium perfringens ε-Toxin.
The Myelin and Lymphocyte Protein MAL Is Required for Binding and Activity of Clostridium perfringens ε-Toxin.
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DOI：
10.1371/journal.ppat.1004896
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发表时间：
2015-05
期刊：
影响因子：
6.7
通讯作者：
Vartanian T
中科院分区：
文献类型：
--
作者：
Rumah KR;Ma Y;Linden JR;Oo ML;Anrather J;Schaeren-Wiemers N;Alonso MA;Fischetti VA;McClain MS;Vartanian T
产气荚膜梭菌ε -毒素（ETX）是一种强效的成孔毒素，可导致反刍动物发生中枢神经系统（CNS）疾病，其特征为血脑屏障（BBB）功能障碍和白质损伤。ETX被认为是多发性硬化症（MS）的一种潜在致病因子，多发性硬化症是一种人类疾病，始于血脑屏障破坏和中枢神经系统髓鞘形成细胞受损。ETX的受体未知。在此我们表明，ETX与哺乳动物细胞的结合以及细胞毒性都需要四跨膜蛋白脂质髓鞘和淋巴细胞蛋白（MAL）。虽然中国仓鼠卵巢（CHO）原代细胞对ETX有抗性，但在CHO细胞中外源表达MAL可使细胞既能结合ETX，又对ETX介导的细胞死亡敏感。表达大鼠MAL的细胞对ETX的敏感性比表达相似水平人MAL的细胞高约100倍。在MAL的第二个细胞外环插入FLAG序列会消除ETX的结合和细胞毒性。已知ETX能特异性地高亲和力结合肠道上皮、肾小管、脑内皮细胞和髓鞘。我们确定了ETX与这些结构的特异性结合，并且还显示在野生型小鼠中它能结合视网膜微血管和巩膜的鳞状上皮细胞。相比之下，在MAL基因敲除（MAL - / -）小鼠的组织中完全没有ETX结合。此外，MAL - / -小鼠在剂量超过野生型小鼠致症状剂量1000倍时对ETX完全有抗性。我们得出结论，MAL是ETX结合和细胞毒性所必需的。
产气荚膜梭菌ε -毒素是一种强效的成孔毒素，可导致家畜发生严重的中枢神经系统疾病，并被认为可能是多发性硬化症的一种环境诱因。ε -毒素能高度特异性地结合有限的几种宿主细胞类型和结构，例如肠道上皮细胞、血脑屏障内皮细胞和髓鞘。虽然大多数成孔毒素通过与细胞膜上各自的受体特异性相互作用来实现结合，但ε -毒素的受体未知。在本报告中，我们确定髓鞘和淋巴细胞蛋白（MAL）是ε -毒素结合和细胞毒性作用所必需的，并且我们表明其第二个细胞外环在这一新功能中至关重要。在生理水平上，MAL基因靶向缺失的纯合子小鼠对ε -毒素缺乏敏感性，而该毒素在野生型小鼠中是致命的。这些观察结果表明MAL可能是ε -毒素的候选受体。然而，我们尚未证明ε -毒素和MAL之间存在物理相互作用。
Clostridium perfringens ε-toxin (ETX) is a potent pore-forming toxin responsible for a central nervous system (CNS) disease in ruminant animals with characteristics of blood-brain barrier (BBB) dysfunction and white matter injury. ETX has been proposed as a potential causative agent for Multiple Sclerosis (MS), a human disease that begins with BBB breakdown and injury to myelin forming cells of the CNS. The receptor for ETX is unknown. Here we show that both binding of ETX to mammalian cells and cytotoxicity requires the tetraspan proteolipid Myelin and Lymphocyte protein (MAL). While native Chinese Hamster Ovary (CHO) cells are resistant to ETX, exogenous expression of MAL in CHO cells confers both ETX binding and susceptibility to ETX-mediated cell death. Cells expressing rat MAL are ~100 times more sensitive to ETX than cells expressing similar levels of human MAL. Insertion of the FLAG sequence into the second extracellular loop of MAL abolishes ETX binding and cytotoxicity. ETX is known to bind specifically and with high affinity to intestinal epithelium, renal tubules, brain endothelial cells and myelin. We identify specific binding of ETX to these structures and additionally show binding to retinal microvasculature and the squamous epithelial cells of the sclera in wild-type mice. In contrast, there is a complete absence of ETX binding to tissues from MAL knockout (MAL-/-) mice. Furthermore, MAL-/- mice exhibit complete resistance to ETX at doses in excess of 1000 times the symptomatic dose for wild-type mice. We conclude that MAL is required for both ETX binding and cytotoxicity. Clostridium perfringens epsilon-toxin is a potent pore-forming toxin responsible for a devastating central nervous system disease in livestock and has been suggested as a possible environmental trigger for Multiple Sclerosis. Epsilon-toxin binds with great specificity to a restricted number of host cell types and structures, for example gut epithelial cells, blood-brain barrier endothelial cells, and myelin. While most pore-forming toxins achieve binding through specific interaction with respective receptors on the cell membrane, the receptor for epsilon-toxin, however, is unknown. In this report we identify the Myelin and Lymphocyte protein, MAL, as being necessary for binding and cytotoxic effects of epsilon-toxin, and we show its second extracellular loop is critical in this novel function. At a physiological level, mice homozygous for a targeted deletion of the MAL gene lack sensitivity to epsilon-toxin whereas the toxin is lethal in wild-type mice. These observations lead to the possibility that MAL is a candidate receptor for epsilon-toxin. However, we have not demonstrated a physical interaction between epsilon-toxin and MAL.
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影响因子：
0.8
作者：
FINNIE, JW
通讯作者：
FINNIE, JW
DOI：
10.1073/pnas.84.7.1997
发表时间：
1987-04-01
影响因子：
11.1
作者：
ALONSO, MA;WEISSMAN, SM
通讯作者：
WEISSMAN, SM
DOI：
10.1073/pnas.96.11.6241
发表时间：
1999-05-25
影响因子：
11.1
作者：
Cheong, KH;Zacchetti, D;Simons, K
通讯作者：
Simons, K
DOI：
10.1002/path.1700710206
发表时间：
1956-01-01
期刊：
JOURNAL OF PATHOLOGY AND BACTERIOLOGY
影响因子：
--
作者：
BULLEN, JJ;BATTY, I
通讯作者：
BATTY, I
影响因子：
0.8
作者：
FINNIE, JW
通讯作者：
FINNIE, JW