Department of Industrial and Environmental Health, Xinxiang Medical University, Xinxiang, Henan Province 453003, China.
Department of Health Inspection and Quarantine, School of Public Health, Xinxiang Medical University, Xinxiang, Henan Province 453003, China.
Mediators Inflamm. 2019 Nov 15;2019:3437104. doi: 10.1155/2019/3437104. eCollection 2019.
Exposure to diesel exhaust particles (DEPs) has been associated with increased incidence of cardiopulmonary diseases. This study is aimed at examining the proinflammatory effects of DEP on primary human peripheral blood mononuclear cells (PBMC) and the underlying mechanisms using a human mononuclear cell line, THP-1. DEPs were incubated with the PBMC and THP-1 cells for 24 h, respectively. The supernatants were collected and subjected to measurement of proinflammatory mediators including interleukin 8 (IL-8) or tumor necrosis factor (TNF) by ELISA. Levels of reactive oxygen species (ROS) were determined using flow cytometry. Phosphorylation of the epidermal growth factor receptor (EGFR) was examined with immunoblotting. Exposure to DEP induced a concentration-dependent increase in the expression of IL-8 and TNF in the PBMC and THP-1 cells. Further mechanistic studies with THP-1 cells indicated that DEP stimulation increased intracellular levels of ROS, an indicator of oxidative stress, and phosphorylation of the EGFR, indicative of EGFR activation. Pretreatment of THP-1 cells with the antioxidant N-acetyl-L-cysteine (NAC) markedly blunted DEP-induced EGFR phosphorylation, indicating that oxidative stress was involved in DEP-induced EGFR activation. Furthermore, the pretreatment of THP-1 cells with either NAC or a selective EGFR inhibitor significantly blocked DEP-induced IL-8 expression, implying that oxidative stress and subsequent EGFR activation mediated DEP-induced inflammatory response. In summary, DEP stimulation increases the expression of proinflammatory mediators in human mononuclear cells, which is regulated by oxidative stress-EGFR signaling pathway.
暴露于柴油废气颗粒（DEP）已与心肺疾病发病率增加有关。本研究旨在使用单核细胞系 THP-1 检查 DEP 对原代人外周血单核细胞（PBMC）的促炎作用及其潜在机制。DEP 分别与 PBMC 和 THP-1 细胞孵育 24 小时。收集上清液，并通过 ELISA 测定包括白细胞介素 8（IL-8）或肿瘤坏死因子（TNF）在内的促炎介质。使用流式细胞术测定活性氧（ROS）的水平。用免疫印迹法检查表皮生长因子受体（EGFR）的磷酸化。DEP 的暴露诱导 PBMC 和 THP-1 细胞中 IL-8 和 TNF 的表达呈浓度依赖性增加。用 THP-1 细胞进行的进一步机制研究表明，DEP 刺激增加了 ROS 的细胞内水平，ROS 是氧化应激的指标，并且 EGFR 的磷酸化，表明 EGFR 的激活。THP-1 细胞用抗氧化剂 N-乙酰-L-半胱氨酸（NAC）预处理明显减弱了 DEP 诱导的 EGFR 磷酸化，表明氧化应激参与了 DEP 诱导的 EGFR 激活。此外，THP-1 细胞用 NAC 或选择性 EGFR 抑制剂预处理可显著阻断 DEP 诱导的 IL-8 表达，这表明氧化应激和随后的 EGFR 激活介导了 DEP 诱导的炎症反应。总之，DEP 刺激增加了人单核细胞中促炎介质的表达，这受氧化应激-EGFR 信号通路的调节。
