Gene expression changes induced by valproate in the process of rat hippocampal neural stem cells differentiation

Valproate (VPA), an effective clinical approved anti‐epileptic drug and mood stabilizer, has been believed to induce neuronal differentiation at the expense of inhibiting astrocytic and oligodendrocytic differentiation. Nevertheless, the involving mechanisms of it remain unclear yet. In the present study, we explored the global gene expression changes of fetus rat hippocampal neural stem cells following VPA treatment by high‐throughput microarray. We obtained 874 significantly upregulated genes and 258 obviously downregulated genes (fold change > 2 and P < 0.05). Then, we performed gene ontology and pathway analyses of these differentially expressed genes and chose several genes associated with nervous system according to gene ontology analysis to conduct expression analysis to validate the reliability of the array results as well as reveal possible mechanisms of VPA. To get a better comprehension of the differentially regulated genes by VPA, we conducted protein–protein association analysis of these genes, which offered a source for further studies. In addition, we made the overlap between the VPA‐downregulated genes and the predicted target genes of VPA‐upregulated microRNAs (miRNAs), which were previously demonstrated. These overlapped genes may provide a source to find functional VPA/miRNA/mRNA axes during neuronal differentiation. This study first constructed a comprehensive potential downstream gene map of VPA in the process of neuronal differentiation.     

Cell surface N-glycans mediated isolation of mouse neural stem cells

The isolation of neural stem cells (NSCs) from the brain has been hampered by the lack of valid cell surface markers and the requirement for long-term in vitro cultivation that may lead to phenotype deterioration. However, few suitable specific cell surface antigens are available on NSCs that could be used for their prospective isolation. The present study demonstrated that the expression of complex type asparagine-linked oligosaccharide ( N- glycans) was detected on brain cells dissociated from embryonic and adult brain using Phaseolus vulgaris erythroagglutinating lectin (E-PHA) which binds to biantennary complex type N- glycans, and demonstrated that E-PHA bound preferentially to purified NSCs, but not to neurons, microglia, or oligodendrocyte precursor cells. The labeling of dissociated mouse embryonic brain cells or adult brain cells with E-PHA enabled the enrichment of NSCs by 25-fold or 9-fold of the number of neurosphere-forming cells in comparison to that of unsorted cells, respectively. Furthermore, a lectin blot analysis revealed the presence of several glycoproteins which were recognized by E-PHA in the membrane fraction of the proliferating NSCs, but not in the differentiated cells. These results indicate that complex type N- glycans is a valuable cell surface marker for living mouse NSCs from both the embryonic and adult brain.     

Purification and characterization of human neural stem and progenitor cells

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Isolation and characterization of the CD133+ precursors from the ventricular zone of human fetal brain by magnetic affinity cell sorting

A fast and effective method to enrich large number of neural precursors from the ventricular zone of human fetus by magnetic affinity cell sorting (MACS) is reported. After incubation with phycoerythrin (PE)-conjugated anti-CD133 antibodies and anti-PE magnetic beads followed by one cycle of MACS, CD133(+) cells were harvested at 85% purity as confirmed by flow-cytometry and immunocytochemistry. In contrast to CD133(-) cells, these CD133(+) cells initiated primary and secondary neurospheres in culture, and the progeny of sorted cells could be differentiated into both neurons and glia, indicating that these highly enriched cells are capable of self-renewal and multi-lineage potential.     

溶血磷脂酸促进离体大鼠胚胎神经干细胞的增殖及其向胆碱能神经元分化

溶血磷脂酸（1ysophosphatidic acid,LPA）是一种细胞外磷脂信号。本研究用[^3H]-胸腺嘧啶掺入法、免疫细胞化学和Western blot等技术,观察了LPA对体外培养的大鼠胚胎神经干细胞（neural stem cells,NSCs）的增殖以及向MAF2标记的一般神经元和ChAT标记的胆碱能神经元的分化的影响。结果显示：（1）在特殊的无血清培养基中加入低浓度的LPA（0．01-1．0μmol/L）后,NSCs对【^3H】-胸腺嘧啶的摄入呈剂量依赖性增加,表明LPA对NSCs有显著的促增殖作用;（2）在培养基中加入胎牛血清以诱导NSCs的分化,发现低浓度的LPA增加MAF2阳性和ChAT阳性神经元的比例,0．1μmol／L LPA引起的增加达到峰值;（3）Western blot分析显示LPA促进了MAP2和ChAT的表达;（4）在诱导NSCs出现分化早期,用倒置显微镜观察到低浓度的LPA明显促进细胞突起的生长和细胞的迁移。以上结果表明,低浓度LPA在一定范围内可以促进NSCs的增殖、并分化为一般的MAP2阳性神经元和特殊的胆碱能神经元,而且LPA可以促进在分化早期出现的神经元或神经胶质细胞前体细胞的迁移和突起生长。     

Derivation of neural precursor cells from human ES cells at 3% O(2) is efficient, enhances survival and presents no barrier to regional specification and functional differentiation

In vitro stem cell systems traditionally employ oxygen levels that are far removed from the in vivo situation. This study investigates whether an ambient environment containing a physiological oxygen level of 3% (normoxia) enables the generation of neural precursor cells (NPCs) from human embryonic stem cells (hESCs) and whether the resultant NPCs can undergo regional specification and functional maturation. We report robust and efficient neural conversion at 3% O(2), demonstration of tri-lineage potential of resultant NPCs and the subsequent electrophysiological maturation of neurons. We also show that NPCs derived under 3% O(2) can be differentiated long term in the absence of neurotrophins and can be readily specified into both spinal motor neurons and midbrain dopaminergic neurons. Finally, modelling the oxygen stress that occurs during transplantation, we demonstrate that in vitro transfer of NPCs from a 20 to 3% O(2) environment results in significant cell death, while maintenance in 3% O(2) is protective. Together these findings support 3% O(2) as a physiologically relevant system to study stem cell-derived neuronal differentiation and function as well as to model neuronal injury.     

Osteogenic and neurogenic differentiation of EGFP gene transfected neural stem cells derived from the brain of porcine fetuses at intermediate and late gestational age

The aims of this study were (i) to determine whether NSCs (neural stem cells) could be isolated from the brain of porcine fetuses at intermediate and late gestational age and (ii) to determine if these stem cells could be differentiated in vitro into osteogenic and neurogenic lineages following transfection with a reporter gene, EGFP (enhanced green fluorescence protein). The NSCs were isolated from the brains of porcine fetuses at intermediate and late gestational age and transfected with EGFP gene using lipofection. The transfected NSCs cells were induced to differentiate into cells of osteogenic and neurogenic lineages. Markers associated with NSCs and their osteogenic and neurogenic derivatives were tested by PCR. The results demonstrated that NSCs could be isolated from the brain of porcine fetus at intermediate and late gestational age and that transfected NSCs expressed EGFP and could be induced to differentiate in vitro. NSCs expressed CD‐90, Hes1, Oct4, Sox2 and Nestin, while following differentiation cells expressed markers for osteogenic (osteocalcin and osteonectin) and neurogenic cells such as astrocyte [GFAP (glial fibrillary acidic protein)], oligodendrocyte [GALC (galactosylceramide)] and neuron [NF (neurofilament), ENO2 (enolase 2) and MAP (microtubule‐associated protein)].     

Establishment and characterization of a nerve cell line (NC-HIMT) from HIMT cells derived from a human ovarian immature teratoma with special reference to the induction of neuron differentiation by retinoic acid

A nerve cell line designated NC-HIMT was established from a HIMT cell line derived from a benign ovarian, three germ layer immature teratoma removed from a 21-year-old Japanese female. The HIMT cells were elongated, ellipsoid or spherical in shape, whose karyotype was on the high side of normal diploidy. Small amounts of retinoic acid enhanced differentiation and maturation of the HIMT cells into nervous tissue, and the NC-HIMT cell line was established by the colony isolating technique when the HIMT cell line was cultured in the presence of retinoic acid-supplemented medium. After establishment, the NC-HIMT cell line was cultured and maintained in retinoic acid-free growth medium. Even though these cells were cultured without retinoic acid, the phenotype of nerve cells remained and the cells were also maintained in a state of high normal diploidy. The nerve cells contacted each other with their long cell projections and formed networks. Immunocytochemical observations using anti-bovine NSE, alpha-internexin, neurofilament 200kD, peripherin and GFAP confirmed that the cells were either nerve cells or glia cells. These results assume that HIMT cells, which were derived from an immature teratoma, have progenitor and/or stem cells which can differentiate into nerve and/or glial cells.     

The evolutionary young miR-1290 favors mitotic exit and differentiation of human neural progenitors through altering the cell cycle proteins

Regulation of cellular proliferation and differentiation during brain development results from processes requiring several regulatory networks to function in synchrony. MicroRNAs are part of this regulatory system. Although many microRNAs are evolutionarily conserved, recent evolution of such regulatory molecules can enable the acquisition of new means of attaining specialized functions. Here we identify and report the novel expression and functions of a human and higher primate-specific microRNA, miR-1290, in neurons. Using human fetal-derived neural progenitors, SH-SY5Y neuroblastoma cell line and H9-ESC-derived neural progenitors (H9-NPC), we found miR-1290 to be upregulated during neuronal differentiation, using microarray, northern blotting and qRT-PCR. We then conducted knockdown and overexpression experiments to look at the functional consequences of perturbed miR-1290 levels. Knockdown of miR-1290 inhibited differentiation and induced proliferation in differentiated neurons; correspondingly, miR-1290 overexpression in progenitors led to a slowing down of the cell cycle and differentiation to neuronal phenotypes. Consequently, we identified that crucial cell cycle proteins were aberrantly changed in expression level. Therefore, we conclude that miR-1290 is required for maintaining neurons in a differentiated state.     

小鼠胚胎干细胞分化形成拟胚体过程中的细胞程序性死亡

为了检测小鼠胚胎干细胞 (embryonicstemcell ,ES细胞 )体外分化的拟胚体 (embryoidbodies ,EBs)形成过程中细胞程序性死亡 (programmedcelldeath ,PCD)的发生 ,通过悬滴、悬浮培养技术定向诱导未分化的ES细胞分化为拟胚体 ,并用RT PCR检测原始内胚层、原始外胚层、中胚层、内脏内胚层 4种分子标记物在EBs中的表达 .通过TUNEL染色、电镜、激光共聚焦显微镜及Western印迹以确定凋亡发生 .结果表明 :ES细胞体外分化为拟胚体并且表达各胚层相应的分子标记物 ;在拟胚体的发育过程中出现明显的空腔化过程 ,TUNEL染色及电镜观察到凋亡生成 ,同时线粒体膜电位 (ΔΨm)在拟胚体发育过程中降低 ,通过Western印迹检测到caspase3、caspase8的激活 .表明小鼠ES细胞所分化的拟胚体可以作为研究早期胚胎发育的实验模型 ,线粒体在拟胚体的细胞程序性死亡过程中发挥重要的作用 .为进一步利用拟胚体研究细胞程序性死亡及相关信号分子在小鼠胚胎发育早期的作用奠定了基础     

Multi-site evaluation of the BD Stem Cell Enumeration Kit for CD34+ cell enumeration on the BD FACSCanto II and BD FACSCalibur flow cytometers

Background aimsEvaluation of the BD Stem Cell Enumeration Kit was conducted at four clinical sites with flow cytometry CD34⁺ enumeration to assess agreement between two investigational methods: (i) the BD FACSCanto II and BD FACSCalibur systems and (ii) the predicate method (Beckman Coulter StemKit and StemTrol, Immunotech SAS, Beckman Coulter, Marseille Cedex 9, France).MethodsLeftover and delinked specimens (n = 1032) from clinical flow cytometry testing were analyzed on the BD FACSCanto II (n = 918) and BD FACSCalibur (n = 905) in normal and mobilized blood, frozen and thawed bone marrow and leucopheresis and cord blood anticoagulated with citrate phosphate dextrose, anticoagulant citrate dextrose—solution A, heparin and ethylenediaminetetraacetate, alone or in combination. Fresh leucopheresis analysis addressed site equivalency for sample preparation, testing and analysis.ResultsThe mean relative bias showed agreement within predefined parameters for the BD FACSCanto II (−2.81 to 4.31 ±7.1) and BD FACSCalibur (−2.69 to 5.2 ±7.9). Results are reported as absolute and relative differences compared with the predicate for viable CD34⁺, percentage of CD34⁺ in CD45⁺ and viable CD45⁺ populations (or gates). Bias analyses of the distribution of the predicate low, mid and high bin values were done using BD FACSCanto II optimal gating and BD FACSCalibur manual gating for viable CD34⁺, percentage of CD34⁺ in CD45⁺ and viable CD45⁺. Bias results from both investigational methods show agreement. Deming regression analyses showed a linear relationship with R² > 0.92 for both investigational methods.DiscussionIn conclusion, the results from both investigational methods demonstrated agreement and equivalence with the predicate method for enumeration of absolute viable CD34⁺, percentage of viable CD34⁺ in CD45⁺ and absolute viable CD45⁺ populations.     

Effects of chitosan/collagen substrates on the behavior of rat neural stem cells

Spinal cord and brain injuries usually lead to cavity formation. The transplantation by combining stem cells and tissue engineering scaffolds has the potential to fill the cavities and replace the lost neural cells. Both chitosan and collagen have their unique characteristics. In this study, the effects of chitosan and collagen on the behavior of rat neural stem cells (at the neurosphere level) were tested in vitro in terms of cytotoxicity and supporting ability for stem cell survival, proliferation and differentiation. Under the serum-free condition, both chitosan membranes and collagen gels had low cytotoxicity to neurospheres. That is, cells migrated from neurospheres, and processes extended out from these neurospheres and the differentiated cells. Compared with the above two materials, chitosan-collagen membranes were more suitable for the co-culture with rat neural stem cells, because, except for low cytotoxicity and supporting ability for the cell survival, in this group, a large number of cells were observed to migrate out from neurospheres, and the differentiating percentage from neurospheres into neurons was significantly increased. Further modification of chitosan-collagen membranes may shed light on in vivo nerve regeneration by transplanting neural stem cells.     

聚赖氨酸修饰丝素蛋白膜对神经干细胞生长和分化的影响

利用聚赖氨酸修饰丝素蛋白膜,观察其对神经干细胞(NSCs)生长及分化的影响,为中枢神经系统损伤修复材料的选择提供实验基础和理论依据。文中首先制备聚赖氨酸修饰的丝素蛋白膜,并通过核磁共振图谱和紫外-可见光谱进行验证。NSCs分别接种在单纯丝蛋白膜(Silk)、聚赖氨酸修饰的丝蛋白膜(Silk-PIL)和多聚赖氨酸(PLL)上进行培养,分别在1、3、5、7 d时用CCK-8检测NSCs增殖活性。在第7天时,用免疫荧光染色检测NSCs分化情况,Western blotting和TUNEL检测细胞凋亡水平,Real-time PCR检测脑源性神经营养因子(BDNF)mRNA水平。结果表明,核磁共振图谱和紫外-可见光谱证明聚赖氨酸成功地接枝到了丝素蛋白膜上,CCK-8检测显示:从第3天开始一直到第7天,NSCs在Silk-PIL上的增殖活性要显著高于Silk组(P0.05),而与PLL组无显著性差异(P0.05)。免疫荧光观察显示,NSCs在Silk-PIL上分化成神经元的细胞显著多于Silk组(P0.05),而与PLL组无显著性差异,3个组之间分化为星型胶质细胞的数量并无显著性差异。Western blotting和TUNEL检测结果表明Silk-PIL组NSCs凋亡程度显著小于Silk组(P0.05),但与PLL组无显著性差异(P0.05)。RT-PCR结果显示,NSCs在Silk-PIL和PLL组的BDNFmRNA表达水平显著高于Silk组(P0.05)。结果表明,聚赖氨酸修饰的丝素蛋白膜能够促进NSCs的增殖活性并减少NSCs细胞凋亡,同时促进NSCs向神经元方向分化,有望成为新型组织工程支架材料搭载NSCs移植修复中枢神经系统损伤。     

Effects of sulforaphane on neural stem cell proliferation and differentiation

Sulforaphane (SFN) is a natural organosulfur compound with anti‐oxidant and anti‐inflammation properties. The objective of this study is to investigate the effect of SFN on the proliferation and differentiation of neural stem cells (NSC). NSCs were exposed to SFN at the concentrations ranging from 0.25 to 10 µM. Cell viability was evaluated with MTT assay and lactate dehydogenase (LDH) release assay. The proliferation of NSCs was evaluated with neurosphere formation assay and Ki‐67 staining. The level of Tuj‐1 was evaluated with immunostaining and Western blot to assess NSC neuronal differentiation. The expression of key proteins in the Wnt signaling pathway, including β‐catenin and cyclin D1, in response to SFN treatment or the Wnt inhibitor, DKK‐1, was determined by Western blotting. No significant cytotoxicity was seen for SFN on NSCs with SFN at concentrations of less than 10 µM. On the contrary, SFN of low concentrations stimulated cell proliferation and prominently increased neurosphere formation and NSC differentiation to neurons. SFN treatment upregulated Wnt signaling in the NSCs, whereas DKK‐1 attenuated the effects of SFN. SFN is a drug to promote NSC proliferation and neuronal differentiation when used at low concentrations. These protective effects are mediated by Wnt signaling pathway.     

Study of neuroprotective function of Ginkgo biloba extract (EGb761) derived‐flavonoid monomers using a three‐dimensional stem cell‐derived neural model

An in vitro three‐dimensional (3D) cell culture system that can mimic organ and tissue structure and function in vivo will be of great benefit for drug discovery and toxicity testing. In this study, the neuroprotective properties of the three most prevalent flavonoid monomers extracted from EGb 761 (isorharmnetin, kaempferol, and quercetin) were investigated using the developed 3D stem cell‐derived neural co‐culture model. Rat neural stem cells were differentiated into co‐culture of both neurons and astrocytes at an equal ratio in the developed 3D model and standard two‐dimensional (2D) model using a two‐step differentiation protocol for 14 days. The level of neuroprotective effect offered by each flavonoid was found to be aligned with its effect as an antioxidant and its ability to inhibit Caspase‐3 activity in a dose‐dependent manner. Cell exposure to quercetin (100 µM) following oxidative insult provided the highest levels of neuroprotection in both 2D and 3D models, comparable with exposure to 100 µM of Vitamin E, whilst exposure to isorhamnetin and kaempferol provided a reduced level of neuroprotection in both 2D and 3D models. At lower dosages (10 µM flavonoid concentration), the 3D model was more representative of results previously reported in vivo. The co‐cultures of stem cell derived neurons and astrocytes in 3D hydrogel scaffolds as an in vitro neural model closely replicates in vivo results for routine neural drug toxicity and efficacy testing. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:735–744, 2016