Beckman Laser Institute and Medical Clinic, University of California, Irvine, Irvine, California, United States of America.
Department of Neurology, University of California, Irvine, Irvine, California, United States of America.
PLoS One. 2018 Apr 30;13(4):e0196153. doi: 10.1371/journal.pone.0196153. eCollection 2018.
This study aims to understand the phagocytic response of astrocytes to the injury of neurons or other astrocytes at the single cell level. Laser nanosurgery was used to damage individual cells in both primary mouse cortical astrocytes and an established astrocyte cell line. In both cases, the release of material/substances from laser-irradiated astrocytes or neurons induced a phagocytic response in near-by astrocytes. Propidium iodide stained DNA originating from irradiated cells was visible in vesicles of neighboring cells, confirming phagocytosis of material from damaged cortical cells. In the presence of an intracellular pH indicator dye, newly formed vesicles correspond to acidic pH fluorescence, thus suggesting lysosome bound degradation of cellular debris. Cells with shared membrane connections prior to laser damage had a significantly higher frequency of induced phagocytosis compared to isolated cells with no shared membrane. The increase in phagocytic response of cells with a shared membrane occurred regardless of the extent of shared membrane (a thin filopodial connection vs. a cell cluster with significant shared membrane). In addition to the presence (or lack) of a membrane connection, variation in phagocytic ability was also observed with differences in injury location within the cell and distance separating isolated astrocytes. These results demonstrate the ability of an astrocyte to respond to the damage of a single cell, be it another astrocyte, or a neuron. This single-cell level of analysis results in a better understanding of the role of astrocytes to maintain homeostasis in the CNS, particularly in the sensing and removal of debris in damaged or pathologic nervous tissue.
本研究旨在从单细胞水平上了解星形胶质细胞对神经元或其他星形胶质细胞损伤的吞噬反应。激光纳米手术用于损伤原代培养的小鼠皮质星形胶质细胞和已建立的星形胶质细胞系中的单个细胞。在这两种情况下，激光照射的星形胶质细胞或神经元释放的物质诱导邻近星形胶质细胞发生吞噬反应。碘化丙啶染色的源自照射细胞的 DNA 可见于邻近细胞的囊泡中，证实了对受损皮质细胞物质的吞噬作用。在存在细胞内 pH 指示剂染料的情况下，新形成的囊泡对应于酸性 pH 荧光，因此提示溶酶体结合的细胞碎片降解。与没有共享膜的孤立细胞相比，激光损伤前具有共享膜连接的细胞的诱导吞噬作用频率显著更高。具有共享膜的细胞吞噬反应的增加与共享膜的程度无关（薄丝状连接与具有显著共享膜的细胞簇）。除了膜连接的存在（或不存在）之外，还观察到吞噬能力的差异，其与细胞内损伤位置和分离的星形胶质细胞之间的距离有关。这些结果表明星形胶质细胞具有响应单个细胞损伤的能力，无论是另一个星形胶质细胞还是神经元。这种单细胞水平的分析有助于更好地理解星形胶质细胞在中枢神经系统中维持内稳态的作用，特别是在损伤或病理性神经组织中检测和清除碎片。
