The effects of centrally administered fluorocitrate via inhibiting glial cells on working memory in rats

Although prefrontal and hippocampal neurons are critical for spatial working memory, the function of glial cells in spatial working memory remains uncertain. In this study we investigated the function of glial cells in rats' working memory. The glial cell

Transplantable neural progenitor populations derived from Rhesus monkey embryonic stem cells

Cell-based therapies using embryonic stem cells (ESCs) in the treatment of neural disease will require the generation of homogenous donor neural progenitor (NP) populations. Here we describe an efficient culture system containing hepatocyte growth factor (HGF) and G5 supplement for the production of highly enriched (88.3% +/- 8.1%)populations of NPs from rhesus monkey ESCs. Additional purification resulted in NP preparations that were 98% nestin positive. Moreover, NPs, as monolayers or neurospheres, could be maintained for prolonged periods of time in media containing HGF+G5 or G5 alone. In vitro differentiation and in vivo transplantation assays showed that NPs could differentiate into neurons, astrocytes, and oligodendrocytes. The kinds and quantities of differentiated cells derived from NPs were closely correlated with their niches in vivo. Glial differentiation was predominant in periventricular areas, whereas cells migrating into the cortex were mostly neurons. Cell counts showed that 2 months after transplantation, approximately 25% of transplanted NPs survived and 65% - 80% of the surviving transplanted cells migrated along the ventricular wall or in a radial fashion. Subcloning demonstrated that several clonal lines derived from NPs expressed nestin and differentiated into three neural lineages in vitro and in rat brains in vivo. In contrast, some subcloned lines showed restricted differentiation both in vitro and in vivo in rat brains. These observations set the stage for obtaining highly enriched NPs and evaluating the efficacy of NP-based transplantation therapy in the nonhuman primate and will provide a platform for probing the molecular mechanisms that control neural induction.

猕猴胚胎干细胞的神经谱系分化及胶质祖细胞迁移机理研究

由于伦理和材料来源的限制，目前对灵长类早期神经发育缺乏深入地了解。与啮齿类动物相比，猕猴在遗传和生理上与人类更接近，因此猕猴胚胎干细胞(rESCs)研究具有重要的研究价值，不仅能为研究发育生物学基础理论提供良好的模型，而且可为细胞替代性治疗提供大量的供体细胞。本文以rESCs为主要研究对象，在rESCs定向分化为神经细胞的基础上着重研究神经谱系分化及调控胶质祖细胞迁移的机理。主要结论如下：1) rESCs来源的神经上皮干/前体细胞(NEPs)主要变为辐射状胶质细胞(RG)后再通过中间类型的祖细胞——神经元祖细胞(NPs)和胶质祖细胞(GPs)——分别分化为神经元和胶质细胞。同时，NEPs/RG细胞群具有早期神经管背-腹和前-后轴空间特性。NEPs/RG的维持受Notch和FGFR信号作用。此外，实验中还纯化和鉴定了猕猴胶质限定性前体细胞(GRPs)。结果表明，rESCs的神经谱系分化能够模拟体内发育过程，并与啮齿类动物早期神经谱系变化过程相似。2) 气体信号分子NO(由10μM—250μM SNP供体释放)促进rESCs来源的A2B5+/Nestin/PSA-NCAM胶质祖细胞迁移。进一步研究发现Netrin-DCC信号通路介导了NO启动的细胞迁移过程。同时，Ca2也参与调控胶质祖细胞的迁移。此外，细胞外基质和整合素α6亦可能与Netrin-DCC相互作用调控细胞迁移。结果显示，NO通过激活一个复杂的信号网络系统调控胶质祖细胞迁移。本实验的研究结果有助于揭示灵长类中枢神经系统发育的机理，同时也能为治疗神经系统退行性疾病提供阶段特异性的供体细胞。