Abstract：
PM2.5 is known to induce lung injury, but its toxic effects on lung regenerative machinery and the underlying mechanisms remain unknown. In this study, primary mouse alveolar type 2 (AT2) cells, considered stem cells in the gas-exchange barrier, were sorted using fluorescence-activated cell sorting. By developing microfluidic technology with constricted microchannels, we observed that both passage time and impedance opacities of mouse AT2 cells were reduced after PM2.5, indicating that PM2.5 induced a more deformable mechanical property and a higher membrane permeability. In vitro organoid cultures of primary mouse AT2 cells indicated that PM2.5 is able to impair the proliferative potential and self-renewal capacity of AT2 cells but does not affect AT1 differentiation. Furthermore, cell senescence biomarkers, p53 and γ-H2A.X at protein levels, P16ink4a and P21 at mRNA levels were increased in primary mouse AT2 cells after PM2.5 stimulations as shown by immunofluorescent staining and quantitative PCR analysis. Using several advanced single-cell technologies, this study sheds light on new mechanisms of the cytotoxic effects of atmospheric fine particulate matter on lung stem cell behavior.
摘要：
已知PM2.5会引起肺损伤，但其对肺再生机制的毒性作用和潜在机制仍不清楚。在这项研究中,原代小鼠肺泡2型（AT2）细胞，被认为是气体交换屏障中的干细胞，使用荧光激活细胞分选进行分选。通过开发具有狭窄微通道的微流控技术，我们观察到PM2.5后小鼠AT2细胞的传代时间和阻抗不透明度均降低，这表明PM2.5诱导了更可变形的机械性能和更高的膜通透性。原代小鼠AT2细胞的体外类器官培养表明，PM2.5能够损害AT2细胞的增殖潜力和自我更新能力，但不影响AT1的分化。此外，细胞衰老生物标志物，p53和γ-H2A。蛋白质水平的X，如免疫荧光染色和定量PCR分析所示，在PM2.5刺激后，原代小鼠AT2细胞中P16ink4a和P21的mRNA水平增加。使用几种先进的单细胞技术，本研究揭示了大气细颗粒物对肺干细胞行为的细胞毒性作用的新机制。
