Nestin-CreER mice reveal DNA synthesis by nonapoptotic neurons following cerebral ischemia-hypoxia
Nestin-CreER mice reveal DNA synthesis by nonapoptotic neurons following cerebral ischemia-hypoxia
复制标题
DOI：
10.1093/cercor/bhl164
复制
发表时间：
2007-11-01
期刊：
影响因子：
3.7
通讯作者：
Kuan, Chia-Yi
中科院分区：
文献类型：
--
作者：
Burns, Kevin A.;Ayoub, Albert E.;Kuan, Chia-Yi
检测神经发生的标准方法使用溴脱氧尿苷（BrdU）标记DNA合成，然后用神经元标记物进行双标记。然而，DNA合成可能发生在与神经发生无关的事件中，包括非整倍体和流产的细胞周期折返。因此，重要的是要用BrduU掺入以外的方法来证实神经发生。为此，我们已经产生了转基因nestin-CreER小鼠表达他莫昔芬诱导的Cre重组酶的控制下的巢蛋白增强子。当与普遍存在的增强型绿色荧光蛋白（EGFP）-Crereporter细胞系杂交时，双转基因动物可以在他莫昔芬诱导后显示nestin阳性的祖细胞及其携带EGFP的后代。该系统具有许多应用，包括胚胎神经祖细胞的可视化，出生后转化的放射状胶质细胞的检测，并标记在脑室下区（SVZ）的成年神经祖细胞。为了研究SVZ祖细胞对中风后细胞替代的贡献，用他莫昔芬诱导的小鼠进行局灶性缺血或缺血-缺氧联合攻击，然后注射BrdU。该分析显示，局灶性缺血后SVZ外仅有极少数EGFP阳性细胞，但海马神经元的DNA合成稳健，缺血缺氧后无立即细胞死亡。这些结果表明，nestin-CreER系统是一个有用的工具，用于检测胚胎和成人神经发生。他们还证实了实验性脑损伤后老年神经元存在非增殖性DNA合成。
The standard method of detecting neurogenesis uses bromodeoxyuridine (BrdU) to label DNA synthesis followed by double labeling with neuronal markers. However, DNA synthesis may occur in events unrelated to neurogenesis including aneuploidy and abortive cell cycle reentry. Hence, it is important to confirm neurogenesis with methods other than BrduU incorporation. To this end, we have generated transgenic nestin-CreER mice that express tamoxifen-inducible Cre recombinase under the control of a nestin enhancer. When crossed with a ubiquitous Enhanced Green Fluorescent Protein (EGFP)-Crereporter line, the bitransgenic animals can reveal the nestin-positive progenitors and their progeny with EGFP after tamoxifen induction. This system has many applications including visualization of embryonic neural progenitors, detection of postnatally transformed radial glial cells, and labeling adult neural progenitors in the subventricular zone (SVZ). To examine the contribution of SVZ progenitors to cell replacement after stroke, tamoxifen-induced mice were challenged with focal ischemia or combined ischemia-hypoxia followed by BrdU injection. This analysis revealed only very few EGFP-positive cells outside the SVZ after focal ischemia but robust DNA synthesis by hippocampal neurons without immediate cell death following ischemia-hypoxia. These results suggest that the nestin-CreER system is a useful tool for detecting embryonic and adult neurogensis. They also confirm the existence of nonproliferative DNA synthesis by old neurons after experimental brain injury.