Bez Alessandra, Corsini Elena, Curti Daniela, Biggiogera Marco, Colombo Augusto, Nicosia Roberto Francesco, Pagano Stefano Filippo, Parati Eugenio Agostino
Laboratory of Neurobiology, Department of Neurobiology and Neurorestorative Therapies, National Neurological Institute C. Besta, Via Celoria 11, 20133 Milan, Italy.
Brain Res. 2003 Dec 12;993(1-2):18-29. doi: 10.1016/j.brainres.2003.08.061.
Despite recent advances in our understanding of neural stem cell (NSC) biology, the free-floating structures generated by these cells in vitro, the "neurospheres", have not been fully characterized. To fill this gap, we examined neurospheres and neurosphere-derived NSCs by confocal microscopy, electron microscopy (EM) and cytofluorimetry. Here, we show that neurospheres and neurosphere-forming cells are morphologically and functionally heterogeneous. Confocal microscopy reveals differences in cell size, viability, cytoplasmic content and in the presence and distribution of active mitochondria. By electron microscopy, neurospheres appear as complex structures in which biological events such as mitosis, apoptosis and even phagocytosis are influenced by NSCs localization within the architecture of the neurosphere. NSCs derived from neurospheres are not synchronized and are represented in all phases of the cell cycle. Cytofluorimetric studies demonstrate NSCs' heterogeneity in cell size by forward scatter (FSC) analysis, and in cytoplasmic granularity by side scatter (SSC) profiling. These findings may contribute to our understanding of the morphogenesis of the neurospheres, particularly as this process relates to the high environmental adaptability of the NSCs and the reported existence of different subpopulations of neural stem cells.
尽管我们对神经干细胞（NSC）生物学的理解最近取得了进展，但这些细胞在体外产生的自由漂浮结构，即“神经球”，尚未得到充分表征。为了填补这一空白，我们通过共聚焦显微镜、电子显微镜（EM）和细胞荧光分析对神经球和神经球衍生的神经干细胞进行了研究。在这里，我们表明神经球和形成神经球的细胞在形态和功能上是异质的。共聚焦显微镜揭示了细胞大小、活力、细胞质含量以及活性线粒体的存在和分布方面的差异。通过电子显微镜观察，神经球呈现为复杂的结构，其中有丝分裂、凋亡甚至吞噬作用等生物学事件受神经干细胞在神经球结构内的定位影响。源自神经球的神经干细胞不同步，处于细胞周期的所有阶段。细胞荧光分析研究通过前向散射（FSC）分析证明了神经干细胞在细胞大小方面的异质性，并通过侧向散射（SSC）分析证明了其在细胞质颗粒度方面的异质性。这些发现可能有助于我们理解神经球的形态发生，特别是因为这一过程与神经干细胞的高环境适应性以及所报道的不同神经干细胞亚群的存在有关。
