Zeng Zhenguo, Li Dan, Liu Fen, Zhou Chaoqi, Shao Qiang, Ding Chengzhi, Qing Cheng, Wang Xuzhen, Hu Zhiguo, Qian Kejian
Department of Critical Care Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
Department of Critical Care Medicine, Inner Mongolia People's Hospital, Hohhot, Inner Mongolia, China.
J Cell Biochem. 2019 May;120(5):8547-8560. doi: 10.1002/jcb.28142. Epub 2018 Dec 5.
The effects and mechanisms of mitochondrial DNA (mtDNA) in the development of sepsis-induced lung injury is not well understood. In our present study, we studied the mtDNA effects in sepsis-induced lung injury model, in vitro and in vivo. Compared with the Normal group, the lung histopathological score, the number of positive apoptosis cell, wet/dry (W/D) ratio and TNF-α, IL-1β, and IL-6 concentrations of lipopolysaccharides (LPSs) and mtDNA groups were significantly increased (P < 0.001, respectively). Meanwhile, the lung histopathological score, positive W/D ratio, number of apoptosis cell and tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6 concentrations of LPS + mtDNA and small interfering RNA (siRNA)-NC + LPS + mtDNA groups were significantly upregulated compared with those of LPS group (P < 0.05, respectively). However, the lung histopathological score, the number of positive apoptosis cell, W/D ratio and TNF-α, IL-1β, and IL-6 concentrations were significantly improved within the toll-like receptor (TLR9)siRNA + LPS + mtDNA group compared with the LPS group (P < 0.01, respectively). The TLR9, MyD88, and NF-κB proteins or gene expressions of the LPS group and mtDNA group were significantly upregulated compared with those of Normal group by Western blot analysis or immunohistochemistry assay (P < 0.01, respectively), and the TLR9, MyD88, and NF-κB proteins or gene expressions of LPS + mtDNA and siRNA-NC + LPS + mtDNA groups were significantly enhanced compared with those of LPS group (P < 0.05, respectively). However, the TLR9, MyD88, and NF-κB proteins or gene expressions of TLR9siRNA + LPS + mtDNA group were significantly suppressed compared with those of the LPS group (P < 0.01, respectively). In conclusion, mtDNA could provoke lung injury induced by sepsis via regulation of TLR9/MyD88/NF-κB pathway in vitro and in vivo.
线粒体DNA（mtDNA）在脓毒症诱导的肺损伤发展中的作用及机制尚未完全明确。在我们目前的研究中，我们在体外和体内研究了mtDNA在脓毒症诱导的肺损伤模型中的作用。与正常组相比，脂多糖（LPS）组和mtDNA组的肺组织病理评分、凋亡阳性细胞数、湿/干（W/D）比值以及TNF-α、IL-1β和IL-6浓度均显著升高（P均<0.001）。同时，与LPS组相比，LPS+mtDNA组和小干扰RNA（siRNA）-NC+LPS+mtDNA组的肺组织病理评分、阳性W/D比值、凋亡细胞数以及肿瘤坏死因子-α（TNF-α）、白细胞介素（IL）-1β和IL-6浓度均显著上调（P均<0.05）。然而，与LPS组相比，Toll样受体（TLR9）siRNA+LPS+mtDNA组的肺组织病理评分、凋亡阳性细胞数、W/D比值以及TNF-α、IL-1β和IL-6浓度均显著改善（P均<0.01）。通过蛋白质印迹分析或免疫组织化学检测，与正常组相比，LPS组和mtDNA组的TLR9、MyD88和NF-κB蛋白或基因表达均显著上调（P均<0.01），与LPS组相比，LPS+mtDNA组和siRNA-NC+LPS+mtDNA组的TLR9、MyD88和NF-κB蛋白或基因表达均显著增强（P均<0.05）。然而，与LPS组相比，TLR9siRNA+LPS+mtDNA组的TLR9、MyD88和NF-κB蛋白或基因表达均显著受到抑制（P均<0.01）。总之，mtDNA可通过在体外和体内调节TLR9/MyD88/NF-κB通路引发脓毒症诱导的肺损伤。
