2017年7月25日，国际学术权威刊物自然出版集团旗下《Nature》杂志在线发表了美国爱因斯坦医学院蔡东升研究组的一篇研究论文，研究表明以小鼠为实验对象，移植或减少其健康下丘脑的成体神经干细胞(NSC)，能够相应减慢或加速机体老化。

        虽然人们已经知道神经系统能控制老化，而且最近的研究证明，下丘脑在此过程中的作用尤其重要，但身体老化的表现具体是如何产生的却并不清楚，科学家需要开展更深入的研究来确定以上联系是否也适用于人类。

        成体神经干细胞存在于大脑某些区域，特别是下丘脑。这是一类具有分裂潜能和自更新能力的母细胞，可以通过不对等的分裂方式产生神经组织的各类细胞，它们也能够调节神经发生——神经元的形成以及大脑的其他几项功能，而科学家们认为，神经发生的减弱与老化引起的疾病有关。

        研究发现下丘脑能够导致系统性老化。在此基础之上，他们利用多个小鼠模型，研究下丘脑成体神经干细胞是否导致这一过程发生。通过激发小鼠特定成体神经干细胞的损耗，研究团队观察到，小鼠出现了加速的、类似老化的生理变化或生命周期缩短;相反，当向中年小鼠移植健康细胞时，则老化速度减慢，小鼠寿命延长。

        研究还显示，外泌体携带的microRNAs(微小核糖核酸)能够部分调节下丘脑成体神经干细胞的抗老化效应，并在下丘脑成体神经干细胞进入脑脊髓液后发挥相应作用。

        论文作者总结称，下丘脑成体神经干细胞减少，其实是全身老化的重要原因，这个最新发现证实了他们最初的假设。

        原文链接：

Hypothalamic stem cells control ageing speed partly through exosomal miRNAs

        原文摘要：

        It has been proposed that the hypothalamus helps to control ageing, but the mechanisms responsible remain unclear. Here we develop several mouse models in which hypothalamic stem/progenitor cells that co-express Sox2 and Bmi1 are ablated, as we observed that ageing in mice started with a substantial loss of these hypothalamic cells. Each mouse model consistently displayed acceleration of ageing-like physiological changes or a shortened lifespan. Conversely, ageing retardation and lifespan extension were achieved in mid-aged mice that were locally implanted with healthy hypothalamic stem/progenitor cells that had been genetically engineered to survive in the ageing-related hypothalamic inflammatory microenvironment. Mechanistically, hypothalamic stem/progenitor cells contributed greatly to exosomal microRNAs (miRNAs) in the cerebrospinal fluid, and these exosomal miRNAs declined during ageing, wheras central treatment with healthy hypothalamic stem/progenitor cell-secreted exosomes led to the slowing of ageing. In conclusion, ageing speed is substantially controlled by hypothalamic stem cells, partially through the release of exosomal miRNAs.