The Sialidase NanS Enhances Non-TcsL Mediated Cytotoxicity of Clostridium sordellii.
The Sialidase NanS Enhances Non-TcsL Mediated Cytotoxicity of Clostridium sordellii.
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DOI：
10.3390/toxins8060189
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发表时间：
2016-06-17
期刊：
影响因子：
4.2
通讯作者：
Lyras D
中科院分区：
文献类型：
--
作者：
Awad MM;Singleton J;Lyras D
梭状芽胞杆菌产生大量毒素，以促进它们在宿主环境中的生存。TcsL是梭状芽胞杆菌（Clostridium sordellii）产生的两种主要毒素之一，是梭状芽胞杆菌（Clostridium sordellii）的疾病发病机制所必需的。C. sordellii产生许多其他毒素，但它们在疾病中的作用尚不清楚，尽管先前的研究表明唾液酸酶NanS可能参与严重疾病期间发生的特征性类白血病反应。在这项研究中，我们研究了NanS在梭氏梭菌病发病机制中的作用。我们构建了一个nanS突变体，并发现nanS是梭氏梭氏菌ATCC9714中唯一产生的唾液酸酶，因为在nanS突变体中检测不到唾液酸酶活性。与野生型基因的互补恢复了nanS突变株唾液酸酶的产生。利用唾液酸酶富集培养上清对肠道（Caco2）、阴道（VK2）和宫颈细胞系（End1/E6E7和Ect1/E6E7）进行细胞毒性测定，结果表明NanS对这些细胞没有细胞毒性。然而，富含毒素的上清对阴道和宫颈细胞系的细胞毒能力在NanS的存在下大大增强。TcsL不是观察到的细胞毒性的介质，因为从TcsL缺失菌株中收获的上清液显示出与含TcsL的上清液相似的细胞毒性水平。这项研究表明，NanS与一种或多种未知毒素协同作用，加剧梭氏梭菌介导的宿主组织损伤。
The clostridia produce an arsenal of toxins to facilitate their survival within the host environment. TcsL is one of two major toxins produced by Clostridium sordellii, a human and animal pathogen, and is essential for disease pathogenesis of this bacterium. C. sordellii produces many other toxins, but the role that they play in disease is not known, although previous work has suggested that the sialidase enzyme NanS may be involved in the characteristic leukemoid reaction that occurs during severe disease. In this study we investigated the role of NanS in C. sordellii disease pathogenesis. We constructed a nanS mutant and showed that NanS is the only sialidase produced from C. sordellii strain ATCC9714 since sialidase activity could not be detected from the nanS mutant. Complementation with the wild-type gene restored sialidase production to the nanS mutant strain. Cytotoxicity assays using sialidase-enriched culture supernatants applied to gut (Caco2), vaginal (VK2), and cervical cell lines (End1/E6E7 and Ect1/E6E7) showed that NanS was not cytotoxic to these cells. However, the cytotoxic capacity of a toxin-enriched supernatant to the vaginal and cervical cell lines was substantially enhanced in the presence of NanS. TcsL was not the mediator of the observed cytotoxicity since supernatants harvested from a TcsL-deficient strain displayed similar cytotoxicity levels to TcsL-containing supernatants. This study suggests that NanS works synergistically with an unknown toxin or toxins to exacerbate C. sordellii-mediated tissue damage in the host.