Department of Basic Medical Science, Hangzhou Normal University, China.
Innate Immun. 2019 Jan;25(1):3-12. doi: 10.1177/1753425918809860. Epub 2018 Nov 14.
Pseudomonas aeruginosa-derived pigment pyocyanin (PCN) has been proved to induce cell apoptosis mediated by the generation of reactive oxygen species (ROS), which has been studied mainly in epithelial cells and neutrophils. However, we previously found that the PCN-producing strain PA14 induces cell apoptosis in human NK cell line NK92 more effectively than in PCN-deficient strain PA14-phZ1/2 via a yet undetermined mechanism. In the current study, we found that PCN-induced NK92 cell apoptosis occurs through mitochondrial damage despite inhibiting intracellular ROS generation. Intracellular Ca ([Ca]) and Bcl-2 family proteins act as important "priming signals" for apoptosis. PCN treatment increased [Ca] in NK92 cells more than twofold after 2 h stimulation, whereas the Ca-chelating agent ethylene glycol tetra-acetic acid (EGTA) inhibited apoptosis. PCN triggered the activation of Bim, Bid, Bik, Bak, and phospho-Bad in NK92 cells in a concentration-dependent manner, but these pro-apoptotic Bcl-2 family proteins were not inhibited by EGTA. In this study, we describe the function of PCN in NK92 cells and identify mitochondrial damage as the mechanism underlying the apoptosis. [Ca] and pro-apoptotic Bcl-2 family proteins are novel targets for PCN-induced apoptosis. Clarification of the cytotoxic diversity of PCN provides a new therapeutic target for defense from P. aeruginosa-induced immune cell damage.
铜绿假单胞菌来源的色素绿脓菌素 (PCN) 已被证明可通过产生活性氧物种 (ROS) 诱导细胞凋亡，这主要在上皮细胞和中性粒细胞中进行了研究。然而，我们之前发现产 PCN 的菌株 PA14 通过一种尚未确定的机制比 PCN 缺陷型菌株 PA14-phZ1/2 更有效地诱导人 NK 细胞系 NK92 发生细胞凋亡。在本研究中，我们发现尽管抑制了细胞内 ROS 的产生，PCN 诱导的 NK92 细胞凋亡仍通过线粒体损伤发生。细胞内 Ca([Ca])和 Bcl-2 家族蛋白作为凋亡的重要“启动信号”。PCN 处理在 2 小时刺激后使 NK92 细胞中的[Ca]增加了两倍以上，而钙螯合剂乙二醇四乙酸 (EGTA) 抑制了凋亡。PCN 以浓度依赖性方式触发 NK92 细胞中 Bim、Bid、Bik、Bak 和磷酸化 Bad 的激活，但这些促凋亡 Bcl-2 家族蛋白不受 EGTA 抑制。在本研究中，我们描述了 PCN 在 NK92 细胞中的功能，并确定线粒体损伤是细胞凋亡的机制。[Ca]和促凋亡 Bcl-2 家族蛋白是 PCN 诱导凋亡的新靶点。阐明 PCN 的细胞毒性多样性为防御铜绿假单胞菌诱导的免疫细胞损伤提供了新的治疗靶点。
