Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
J Mol Neurosci. 2010 Mar;40(3):360-6. doi: 10.1007/s12031-009-9326-0. Epub 2010 Jan 27.
Cell-based approaches are a promising therapeutic strategy for treating injuries to the nervous system, but the optimal means to promote neurite extension and direct cellular behavior are unclear. Previous studies have examined the behavior of neural-like cells in ambient air (21% oxygen tension), yet these conditions are not representative of the physiological oxygen microenvironment of neural tissues. We hypothesized that neuronal differentiation of a model neural cell line (PC12) could be controlled by modulating local oxygen tension. Compared to ambient conditions, PC12 cells cultured in reduced oxygen exhibited significant increases in neurite extension and total neurite length, with 4% oxygen yielding the highest levels of both indicators. We confirmed neurite extension was mediated through oxygen-responsive mechanisms using small molecules that promote or inhibit HIF-1alpha stabilization. The hypoxic target gene Vegf was implicated as a neurotrophic factor, as neurite formation at 21% oxygen was mimicked with exogenous VEGF, and a VEGF-neutralizing antibody attenuated neurite formation under reduced oxygen conditions. These findings demonstrate that behavior of neural-like cells is driven by the oxygen microenvironment via VEGF function, and suggest promising approaches for future applications in neural repair.
基于细胞的方法是治疗神经系统损伤的一种很有前途的治疗策略，但促进神经突延伸和直接细胞行为的最佳方法尚不清楚。以前的研究已经研究了在环境空气中（21%氧气张力）类似神经细胞的行为，但这些条件与神经组织的生理氧气微环境并不相符。我们假设通过调节局部氧气张力可以控制模型神经细胞系（PC12）的神经元分化。与环境条件相比，在低氧条件下培养的 PC12 细胞表现出明显增加的神经突延伸和总神经突长度，其中 4%的氧气产生最高水平的两种指标。我们使用促进或抑制 HIF-1alpha 稳定的小分子证实了神经突延伸是通过氧气反应机制介导的。缺氧靶基因 Vegf 被认为是一种神经营养因子，因为在 21%氧气下的神经突形成可以通过外源性 VEGF 模拟，并且 VEGF 中和抗体在低氧条件下减弱了神经突形成。这些发现表明，类似神经细胞的行为是通过 VEGF 功能的氧气微环境驱动的，并为未来神经修复的应用提供了有前途的方法。
