Involvement of protein disulfide isomerase in subtilase cytotoxin-induced cell death in HeLa cells
Involvement of protein disulfide isomerase in subtilase cytotoxin-induced cell death in HeLa cells
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蛋白质二硫键异构酶参与枯草杆菌酶细胞毒素诱导的 HeLa 细胞细胞死亡
DOI：
10.1016/j.bbrc.2020.03.008
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发表时间：
2020
影响因子：
3.1
通讯作者：
Sawa Tomohiro
中科院分区：
文献类型：
--
作者：
Tsutsuki Hiroyasu;Zhang Tianli;Harada Ayaka;Rahman Azizur;Ono Katsuhiko;Yahiro Kinnosuke;Niidome Takuro;Sawa Tomohiro
枯草杆菌酶细胞毒素（SubAB）是由某些肠出血性大肠杆菌菌株产生的细菌AB 5毒素的成员，它切割内质网（ER）中的宿主伴侣BiP，导致ER应激介导的细胞毒性。蛋白质二硫键异构酶（protein disulfide isomerase，PDI）是一种催化蛋白质二硫键形成和断裂的酶，它通过解折叠A亚基调节霍乱毒素等AB 5毒素，使其易位到胞质中而致病。虽然SubAB靶向ER，并且具有与其他AB 5毒素类似的A亚基，但PDI是否可以调节SubAB功能尚不清楚。在这里，我们确定了PDI对SubAB诱导的BiP切割，ER应激反应和HeLa细胞的细胞毒性的作用。我们发现，PDI敲低显著抑制SubAB诱导的BiP切割和eIF2α磷酸化。在PDI敲低后，ER中SubAB的积累受到干扰。最后，细胞活力测定显示PDI敲低和PDI抑制剂消除SubAB诱导的细胞毒性。目前的结果表明，SubAB，细胞摄取后，易位到ER和BiP，可能是由PDI调制的相互作用。鉴定宿主蛋白质对细菌毒素的关键作用，以揭示其致病机制，是开发潜在的化学治疗和新的诊断策略以控制产毒素细菌感染的必要基础。
Subtilase cytotoxin (SubAB) is a member of bacterial AB5toxin produced by certain enterohemorrhagicE. colistrains which cleaves host chaperone BiP in endoplasmic reticulum (ER), leading to ER stress-mediated cytotoxicity. Previous study suggested that protein disulfide isomerase (PDI), an enzyme which catalyzes the formation and breakage of disulfide bonds in proteins, regulates AB5toxin such as cholera toxin by unfolding of A subunit, leading to its translocation into cytosol to induce disease. Although SubAB targets ER and has similar A subunit to that of other AB5toxins, it is unclear whether PDI can modulate the SubAB function. Here we determined the role of PDI on SubAB-induced BiP cleavage, ER stress response and cytotoxicity in HeLa cells. We found that PDI knockdown significantly suppressed SubAB-induced BiP cleavage and eIF2α phosphorylation. The accumulation of SubAB in ER was perturbed upon PDI knockdown. Finally, cell viability assay showed that PDI knockdown and PDI inhibitor canceled the SubAB-induced cytotoxicity. Present results suggested that SubAB, after cellular uptake, translocates into ER and interacts with BiP that might be modulated by PDI. Identification of pivotal role of host proteins on bacterial toxin to elicit its pathogenesis is necessary basis for development of potential chemotherapy and new diagnostic strategy for control of toxin-producing bacterial infections.