Department of Stereotactic and Functional Neurosurgery, Neurocentre, Albert-Ludwig University, Breisacherstrasse 64, 79106 Freiburg im Breisgau, Germany.
Mol Cell Neurosci. 2011 May;47(1):36-44. doi: 10.1016/j.mcn.2011.02.011. Epub 2011 Feb 26.
Differentiation of neuronal progenitor cells (NPCs) in vitro into functional neurons is dependent on a complex cascade of molecular signaling pathways, many of which remain unknown. More specifically, in human NPCs the relationship between the expression of typical neuronal marker proteins and functional properties, such as firing action potential and synaptic transmission, is not well understood. In the present report, the immunocytochemical, morphological and electrophysiological changes that human NPCs undergo during neuronal differentiation in vitro were investigated.
Human NPCs were differentiated toward a neuronal phenotype. The time course of the expression of neuronal markers and morphological cell changes was mapped and passive and active electrophysiological membrane properties assessed, throughout the neuronal maturation process.
The acquisition of neuronal markers preceded functional physiological maturation by several weeks. Cell input resistance decreased in the first 2 weeks as cells became less sensitive to input current, while cell capacitance progressively increased with continued neuronal process growth. Functional maturation was observed only by the fifth/sixth week, preceded by a marked increase in Na+ and K+ currents. In contrast, electrophysiological maturation of rodent precursor cells was observed at the end of the first week in vitro. Functionally, human neuronal cells became capable of firing action potentials and forming active synaptic contacts. Many features of the firing pattern however remained immature.
The results showed that human NPCs develop remarkably slowly and retain immature neuronal features for a prolonged period. The importance of Na-dependent activity for proper neuronal maturation is emphasized.
体外将神经祖细胞 (NPCs) 分化为功能性神经元依赖于一系列复杂的分子信号通路，其中许多通路仍不清楚。更具体地说，在人类 NPCs 中，典型神经元标记蛋白的表达与功能特性（如触发动作电位和突触传递）之间的关系尚未得到很好的理解。在本报告中，研究了人 NPCs 在体外向神经元分化过程中的免疫细胞化学、形态和电生理变化。
将人 NPCs 分化为神经元表型。绘制了神经元标记物表达和形态细胞变化的时间过程，并在整个神经元成熟过程中评估了被动和主动电生理膜特性。
获得神经元标记物的时间早于功能性生理成熟数周。在细胞对输入电流的敏感性降低的前 2 周内，细胞输入电阻降低，而随着神经元过程的持续生长，细胞电容逐渐增加。只有在第五/六周才观察到功能成熟，此前 Na+ 和 K+ 电流明显增加。相比之下，在体外第一周结束时观察到了啮齿动物前体细胞的电生理成熟。在功能上，人神经元细胞能够触发动作电位并形成活跃的突触接触。然而，许多点火模式的特征仍然不成熟。
结果表明，人 NPCs 的发育非常缓慢，并在很长一段时间内保留不成熟的神经元特征。强调了 Na 依赖性活动对适当神经元成熟的重要性。
