Table 2_Aging restricts the initial neural patterning potential of developing neural stem and progenitor cells in the adult brain.xlsx

IntroductionNeurosphere culture is widely used to expand neural stem and progenitor cells (NSPCs) of the nervous system. Understanding the identity of NSPCs, such as the principals involved in spatiotemporal patterning, will improve our chances of using NSPCs for neurodevelopmental and brain repair studies with the ability to direct NSPCs toward distinct fates. Some reports indicate that aging can affect the nature of NSPCs over time. Therefore, in this study, we aimed to investigate how the initial neural patterning of developing NSPCs changes over time.
MethodsIn this research, evidence of changing neural patterning potential in the nervous system over time was presented. Thus, the embryonic and adult-derived NSPCs for cardinal characteristics were analyzed, and then, the expression of candidate genes related to neural patterning using real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) was evaluated at various stages of embryonic (E14 and E18), neonatal, and adult brains. Finally, it was assessed the effect of cell attachment and passage on the initial neural patterning of NSPCs.
ResultsThe analysis of gene expression revealed that although temporal patterning is maintained in vitro, it shows a decrease over time. Embryonic NSPCs exhibited the highest potential for retaining regional identity than neonatal and adult NSPCs. Additionally, it was found that culture conditions, such as cell passaging and attachment status, could affect the initial neural patterning potential, resulting in a decrease over time.
ConclusionOur study demonstrates that patterning potential decreases over time and aging imposes restrictions on preliminary neural patterning. These results emphasize the significance of patterning in the nervous system and the close relationship between patterning and fate determination, raising questions about the application of aged NSPCs in the treatment of neurodegenerative diseases.

引言：神经球培养（neurosphere culture）被广泛用于扩增神经系统的神经干细胞和祖细胞（neural stem and progenitor cells，NSPCs）。明确NSPCs的身份特征——例如参与时空模式化的核心调控原理——有助于提升我们利用NSPCs开展神经发育及脑修复研究的可行性，实现定向诱导NSPCs向特定细胞命运分化的目标。已有研究表明，衰老可随时间推移改变NSPCs的生物学特性。因此，本研究旨在探究发育中NSPCs的初始神经模式化特征随时间的变化规律。

方法：本研究旨在揭示神经系统中神经模式化潜能随时间改变的证据。首先分析胚胎来源与成年来源NSPCs的核心特征，随后借助实时定量逆转录聚合酶链反应（real-time quantitative reverse transcription polymerase chain reaction，RT-qPCR），检测胚胎期（E14、E18）、新生期及成年脑组织不同阶段下与神经模式化相关的候选基因表达水平。最后评估细胞贴壁状态与传代对NSPCs初始神经模式化特征的影响。

结果：基因表达分析显示，尽管体外培养可保留NSPCs的时序模式化特征，但该特征会随时间推移逐渐减弱。与新生期及成年NSPCs相比，胚胎来源NSPCs保留区域身份特征的潜能最高。此外研究发现，细胞传代、贴壁状态等培养条件可影响NSPCs的初始神经模式化潜能，使其随时间逐渐下降。

结论：本研究证实，神经模式化潜能随时间逐渐降低，衰老会对初始神经模式化过程产生限制。上述结果凸显了神经系统中模式化过程的重要性，以及模式化与细胞命运决定之间的紧密关联，同时也为衰老NSPCs在神经退行性疾病治疗中的应用前景提出了待探讨的问题。