Department of Neurology, University Hospital Cologne, Cologne, Germany.
Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Juelich, Germany.
J Tissue Eng Regen Med. 2019 Jun;13(6):960-972. doi: 10.1002/term.2838. Epub 2019 May 21.
In the brain, neural stem cells (NSC) are tightly regulated by external signals and biophysical cues mediated by the local microenvironment or "niche." In particular, the influence of tissue elasticity, known to fundamentally affect the function of various cell types in the body, on NSC remains poorly understood. We, accordingly, aimed to characterize the effects of elastic substrates on critical NSC functions. Primary rat NSC were grown as monolayers on polydimethylsiloxane- (PDMS-) based gels. PDMS-coated cell culture plates, simulating the physiological microenvironment of the living brain, were generated in various degrees of elasticity, ranging from 1 to 50 kPa; additionally, results were compared with regular glass plates as usually used in cell culture work. Survival of NSC on the PDMS-based substrates was unimpaired. The proliferation rate on 1 kPa PDMS decreased by 45% compared with stiffer PMDS substrates of 50 kPa (p < 0.05) whereas expression of cyclin-dependent kinase inhibitor 1B/p27Kip1 increased more than two fold (p < 0.01), suggesting NSC quiescence. NSC differentiation was accelerated on softer substrates and favored the generation of neurons (42% neurons on 1 kPa PDMS vs. 25% on 50 kPa PDMS; p < 0.05). Neurons generated on 1 kPa PDMS showed 29% longer neurites compared with those on stiffer PDMS substrates (p < 0.05), suggesting optimized neuronal maturation and an accelerated generation of neuronal networks. Data show that primary NSC are significantly affected by the mechanical properties of their microenvironment. Culturing NSC on a substrate of brain-like elasticity keeps them in their physiological, quiescent state and increases their neurogenic potential.
在大脑中，神经干细胞（NSC）受到外部信号和生物物理线索的严格调节，这些线索由局部微环境或“龛位”介导。特别是，组织弹性的影响，众所周知，它从根本上影响身体中各种细胞类型的功能，对 NSC 的影响仍知之甚少。因此，我们旨在表征弹性基底对关键 NSC 功能的影响。原代大鼠 NSC 作为单层在聚二甲基硅氧烷（PDMS）基凝胶上生长。PDMS 涂层的细胞培养板，模拟活体大脑的生理微环境，具有从 1 到 50kPa 不等的各种弹性；此外，结果与通常用于细胞培养工作的常规玻璃板进行了比较。NSC 在 PDMS 基基底上的存活未受影响。与 50kPa 的较硬 PMDS 基底相比，1kPa PDMS 上的 NSC 增殖率降低了 45%（p<0.05），而细胞周期蛋白依赖性激酶抑制剂 1B/p27Kip1 的表达增加了两倍以上（p<0.01），表明 NSC 静止。在较软的基底上，NSC 分化加速，并有利于神经元的产生（1kPa PDMS 上产生 42%的神经元，而 50kPa PDMS 上产生 25%的神经元；p<0.05）。在 1kPa PDMS 上产生的神经元的突起比在较硬的 PDMS 基底上产生的神经元的突起长 29%（p<0.05），表明神经元成熟得到优化，神经元网络的生成速度加快。数据表明，原代 NSC 受到其微环境机械性能的显著影响。在具有类似大脑弹性的基底上培养 NSC 可使其保持生理静止状态，并增加其神经发生潜能。
