Keung Albert J, Dong Meimei, Schaffer David V, Kumar Sanjay
Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA 94720, USA.
Sci Rep. 2013;3:1817. doi: 10.1038/srep01817.
Most past studies of the biophysical regulation of stem cell differentiation have focused on initial lineage commitment or proximal differentiation events. It would be valuable to understand whether biophysical inputs also influence distal endpoints more closely associated with physiological function, such as subtype specification in neuronal differentiation. To explore this question, we cultured adult neural stem cells (NSCs) on variable stiffness ECMs under conditions that promote neuronal fate commitment for extended time periods to allow neuronal subtype differentiation. We find that ECM stiffness does not modulate the expression of NeuroD1 and TrkA/B/C or the percentages of pan-neuronal, GABAergic, or glutamatergic neuronal subtypes. Interestingly, however, an ECM stiffness of 700 Pa maximizes expression of pan-neuronal markers. These results suggest that a wide range of stiffnesses fully permit pan-neuronal NSC differentiation, that an intermediate stiffness optimizes expression of pan-neuronal genes, and that stiffness does not impact commitment to particular neuronal subtypes.
过去大多数关于干细胞分化生物物理调节的研究都集中在初始谱系定向或近端分化事件上。了解生物物理输入是否也会影响与生理功能更密切相关的远端终点，如神经元分化中的亚型特异性，将是很有价值的。为了探讨这个问题，我们在可变硬度的细胞外基质（ECM）上培养成年神经干细胞（NSC），培养条件促进神经元命运定向并持续较长时间，以允许神经元亚型分化。我们发现，ECM硬度不会调节NeuroD1和TrkA/B/C的表达，也不会调节泛神经元、GABA能或谷氨酸能神经元亚型的比例。然而，有趣的是，700 Pa的ECM硬度能使泛神经元标志物的表达最大化。这些结果表明，广泛的硬度范围完全允许泛神经元NSC分化，中等硬度能优化泛神经元基因的表达，并且硬度不会影响向特定神经元亚型的定向。
