Key Laboratory of Animal Physiology & Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, China.
J Cell Physiol. 2019 Apr;234(4):3621-3633. doi: 10.1002/jcp.27132. Epub 2018 Nov 23.
N-(3-oxododecanoyl)-l-homoserine lactone (3-oxo-C12-HSL), a quorum-sensing (QS) molecule produced by Gram-negative bacteria in the gastrointestinal tract, adversly impacts host cells. Our previous study demonstrated that 3-oxo-C12-HSL induced a decrease in cell viability via cell apoptosis and eventually disrupted mucin synthesis from LS174T goblet cells. However, the molecular mechanism underlying cell apoptosis and whether pyroptosis was involved in this process are still unknown. In this study, we emphasized on the caspases signal pathway and sterile inflammation to reveal the harmful effects of 3-oxo-C12-HSL on LS174T goblet cells. Our data showed that 3-oxo-C12-HSL is a major inducer of oxidative stress indicated by a high level of intracellular reactive oxygen species (ROS). However, TQ416, an inhibitor of paraoxonase 2, can effectively block oxidative stress. A higher ROS level is the trigger for activating the caspase-1 and 3 cascade signal pathways. Blockade of ROS synthesis and caspase-1 and 3 cascades can obviously rescue the viability of LS174T cells after 3-oxo-C12-HSL treatment. We also found that paralleled with a higher level of ROS and caspases activation, an abnormal expression of proinflammatory cytokines was induced by 3-oxo-C12-HSL treatment; however, the blockage of TLRs-NF-κB pathway cannot restore cell viability and secretary function. These data collectively indicate that 3-oxo-C12-HSL exposure induces damages to cell viability and secretary function of LS174T goblet cells, which is mediated by oxidative stress, cell apoptosis, and sterile inflammation. Overall, the data in this study will provide a better understanding of the harmful impacts of some QS molecules on host cells and their underlying mechanism.
N-(3-氧代十二烷酰基)-L-高丝氨酸内酯(3-氧代-C12-HSL),一种肠道革兰氏阴性菌产生的群体感应(QS)分子,对宿主细胞有不利影响。我们之前的研究表明,3-氧代-C12-HSL 通过细胞凋亡导致细胞活力下降,最终破坏 LS174T 杯状细胞的粘蛋白合成。然而,细胞凋亡的分子机制以及是否涉及细胞焦亡仍不清楚。在这项研究中,我们强调了半胱氨酸天冬氨酸蛋白酶信号通路和无菌性炎症,以揭示 3-氧代-C12-HSL 对 LS174T 杯状细胞的有害影响。我们的数据表明,3-氧代-C12-HSL 是一种主要的氧化应激诱导剂,表现为细胞内活性氧(ROS)水平升高。然而,对氧磷酶 2 的抑制剂 TQ416 可以有效阻断氧化应激。更高的 ROS 水平是激活半胱氨酸天冬氨酸蛋白酶-1 和 3 级联信号通路的触发因素。阻断 ROS 合成和半胱氨酸天冬氨酸蛋白酶-1 和 3 级联可以明显挽救 3-氧代-C12-HSL 处理后 LS174T 细胞的活力。我们还发现,与 ROS 和半胱氨酸天冬氨酸蛋白酶激活水平升高平行的是,3-氧代-C12-HSL 处理诱导促炎细胞因子的异常表达;然而,TLRs-NF-κB 通路的阻断不能恢复细胞活力和分泌功能。这些数据共同表明,3-氧代-C12-HSL 暴露诱导 LS174T 杯状细胞活力和分泌功能受损,这是由氧化应激、细胞凋亡和无菌性炎症介导的。总的来说,这项研究的数据将更好地理解一些 QS 分子对宿主细胞的有害影响及其潜在机制。