Liu Yulin, Zhang Junjie, Li Yabei, Zhao Yuxiang, Kuermanbayi Shuake, Zhuang Jian, Zhang Hua, Xu Feng, Li Fei
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University Xi'an 710049 P. R. China
Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University Xi'an 710049 P. R. China.
Chem Sci. 2023 Nov 28;15(1):171-184. doi: 10.1039/d3sc03504b. eCollection 2023 Dec 20.
Microglia play a crucial role in maintaining the homeostasis of the central nervous system (CNS) by sensing and responding to mechanical and inflammatory cues in their microenvironment. However, the interplay between mechanical and inflammatory cues in regulating microglia activation remains elusive. In this work, we constructed mechanical-inflammatory coupled microenvironment models of microglia by culturing BV2 cells (a murine microglial cell line) on polyacrylamide gels with tunable stiffness and incorporating a lipopolysaccharide (LPS) to mimic the physiological and pathological microenvironment of microglia in the hippocampus. Through characterization of activation-related proteins, cytokines, and reactive oxygen species (ROS) levels, we observed that the LPS treatment induced microglia on a stiff matrix to exhibit overexpression of NOX2, higher levels of ROS and inflammatory factors compared to those on a soft matrix. Additionally, using scanning electrochemical microscopy (SECM), we performed characterization and discovered that microglia on a stiff matrix promoted extracellular ROS production, leading to a disruption in their redox balance and increased susceptibility to LPS-induced ROS production. Furthermore, the respiratory activity and migration behavior of microglia were closely associated with their activation process, with the stiff matrix-LPS-induced microglia demonstrating the most pronounced changes in respiratory activity and migration ability. This work represents the first and dynamic monitoring of microglia activation state alterations under a mechanical-inflammatory coupled microenvironment using SECM. Our findings shed light on matrix stiffness-dependent activation of microglia in response to an inflammatory microenvironment, providing valuable insights into the mechanisms underlying neuroinflammatory processes in the CNS.
小胶质细胞通过感知和响应其微环境中的机械和炎症信号，在维持中枢神经系统（CNS）的稳态中发挥关键作用。然而，机械信号和炎症信号在调节小胶质细胞激活过程中的相互作用仍不清楚。在这项工作中，我们通过在具有可调刚度的聚丙烯酰胺凝胶上培养BV2细胞（一种小鼠小胶质细胞系）并加入脂多糖（LPS），构建了小胶质细胞的机械 - 炎症耦合微环境模型，以模拟海马体中小胶质细胞的生理和病理微环境。通过对激活相关蛋白、细胞因子和活性氧（ROS）水平的表征，我们观察到与在软基质上的小胶质细胞相比，LPS处理诱导硬基质上的小胶质细胞表现出NOX2的过表达、更高水平的ROS和炎症因子。此外，我们使用扫描电化学显微镜（SECM）进行表征，发现硬基质上的小胶质细胞促进细胞外ROS的产生，导致其氧化还原平衡破坏，并增加对LPS诱导的ROS产生的敏感性。此外，小胶质细胞的呼吸活性和迁移行为与其激活过程密切相关，硬基质 - LPS诱导的小胶质细胞在呼吸活性和迁移能力方面表现出最明显的变化。这项工作首次使用SECM对机械 - 炎症耦合微环境下小胶质细胞激活状态的改变进行了动态监测。我们的研究结果揭示了小胶质细胞在炎症微环境下对基质刚度依赖性的激活，为中枢神经系统神经炎症过程的潜在机制提供了有价值的见解。
