Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and Technology, Wuhan, 430074, China.
MoE Key Laboratory for Biomedical Photonics, Collaborative Innovation Center for Biomedical Engineering, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, 430074, China.
Sci China Life Sci. 2019 Sep;62(9):1168-1177. doi: 10.1007/s11427-018-9470-9. Epub 2019 Apr 15.
Mammalian target of rapamycin (mTOR), a serine/threonine kinase orchestrating cellular metabolism, is a crucial immune system regulator. However, it remains unclear how mTOR regulates dendritic cell (DC) function in vivo, especially DC-T cell encounters, a critical step for initiating adaptive immune responses. We dynamically visualized DC-T contacts in mouse lymph node using confocal microscopy and established an encounter model to characterize the effect of mTOR inhibition on DC-T cell encounters using DC morphology. Quantitative data showed mTOR inhibition via rapamycin altered DC shape, with an increased form factor (30.17%) and decreased cellular surface area (20.36%) and perimeter (22.43%), which were associated with Cdc42 protein downregulation (52.71%). Additionally, DCs adopted a similar morphological change with Cdc42 inhibition via ZCL278 as that observed with mTOR inhibition. These morphologically altered DCs displayed low encounter rates with T cells. Time-lapse imaging data of T cell motility supported the simulated result of the encounter model, where antigen-specific T cells appeared to reduce arrest in the lymph nodes of rapamycin-pretreated mice relative to the untreated group. Therefore, mTOR inhibition altered DC morphology in vivo and decreased the DC-T cell encounter rate, as well as Cdc42 inhibition. By establishing an encounter model, our study provides an intuitive approach for the early prediction of DC function through morphological quantification of form factor and area.
哺乳动物雷帕霉素靶蛋白（mTOR）是一种丝氨酸/苏氨酸激酶，协调细胞代谢，是免疫系统的重要调节因子。然而，mTOR 如何调节体内树突状细胞（DC）的功能，特别是 DC-T 细胞的相互作用，这是启动适应性免疫反应的关键步骤，目前尚不清楚。我们使用共聚焦显微镜动态观察了小鼠淋巴结中的 DC-T 接触，并建立了一个相互作用模型，以通过 DC 形态学来描述 mTOR 抑制对 DC-T 细胞相互作用的影响。定量数据显示，雷帕霉素通过 mTOR 抑制改变了 DC 的形状，其形态因子增加（30.17%），细胞表面积减少（20.36%），周长减少（22.43%），这与 Cdc42 蛋白下调（52.71%）有关。此外，用 Cdc42 抑制剂 ZCL278 抑制 DC 也会产生与 mTOR 抑制类似的形态变化。这些形态改变的 DC 与 T 细胞的接触率较低。T 细胞迁移的延时成像数据支持相互作用模型的模拟结果，即与未处理组相比，抗原特异性 T 细胞在雷帕霉素预处理小鼠的淋巴结中似乎减少了停顿。因此，mTOR 抑制改变了体内 DC 的形态，并降低了 DC-T 细胞的相互作用率，以及 Cdc42 的抑制。通过建立相互作用模型，我们的研究通过形态因子和面积的定量分析，为通过形态学量化来早期预测 DC 功能提供了一种直观的方法。
