星形胶质细胞诱导成年神经干细胞的神经发生

在中枢神经系统 ,成年后新神经元发生主要见于两个脑区 ,即室管下区 (ｓｕｂｖｅｎｔｒｉｃｕｌａｒｚｏｎｅ)与海马的颗粒下区 (ｓｕｂｇｒａｎｕｌａｒｚｏｎｅ)。正常情况下 ,除上述脑区外的其它脑区能够产生神经胶质细胞 ,但是不能产生神经元。为了研究神经元和 /或神经胶质细胞对来源于成年的神经干细胞分化的影响 ,Ｓｏｎｇ等分离了成年大鼠海马的神经元和星形胶质细胞 ,将其分别或联合与来自成年的、依赖ＦＧＦ 2的神经干细胞共培养 ,意外地发现神经元促进神经干细胞分化为少突胶质细胞 ,而星形胶质细胞则促进神经干细胞分化为神经…     

RCMV感染星形胶质细胞对神经干细胞分化的影响

探讨大鼠巨细胞病毒（rat cytomegalovirus,RCMV）感染大鼠星形胶质细胞后,对神经干细胞分化的影响。原代分离培养新生大鼠星形胶质细胞和胚胎海马神经干细胞,将星形胶质细胞感染RCMV后和神经干细胞在Transwell24孔共培养体系下进行共培养,同时设对照组;用免疫荧光染色等方法检测神经干细胞与感染RCMV的星形胶质细胞共培养后,其分化细胞中神经元微管相关蛋白（microtubule-associated protein 2,MAP2）和星形胶质细胞胶质纤维酸性蛋白（glial fibril—lary acidic protein,GFAP）的表达。结果发现,感染RCMV的星形胶质细胞与神经干细胞共培养时,神经干细胞分化减慢,分化成的神经元和星形胶质细胞比率低于对照组,提示星形胶质细胞感染RCMV后可抑制神经干细胞的分化,可能与RCMV影响星形胶质细胞合成和分泌各种营养因子,干扰了神经干细胞的分化进程有关。     

大鼠大脑皮质星形胶质细胞条件培养液促进小脑皮质神经元的生长

本研究从大鼠大脑皮质分离、纯化星形胶质细胞,再经培养后收集星形胶质细胞的无血清条件培养液。用盖玻片培养法与快速自动比色微量分析法研究了星形胶质细胞条件培养液对小脑皮质神经元生存以及神经元活力的影响。发现星形胶质细胞条件培养液能够明显提高小脑皮质神经元的体外存活率,增强神经元的活力。表明星形胶质细胞具有神经营养性作用。     

LPS诱导海马星形胶质细胞活化与活化的星形胶质细胞对海马神经元的影响

探讨脂多糖(Lipopolysaccharide,LPS)对长时间存活大鼠海马内星形胶质细胞的反应以及对神经元的影响。方法:本实验用10只健康成年雄性SD大鼠,海马CA3区注射LPS 10μ1．7和14d后,尼氏染色观察神经元的变化,免疫组织化学染色结合图像分析方法观察海马CA3区注射部位胶质纤维酸性蛋白(glial fibrillary acidic protein GFAP)、的表达变化。结果:脂多糖可促进海马星形胶质细胞的活化,但并不能引起海马区神经元的损伤。结论:星形胶质细胞在脑损伤后的脑内炎症反应起了一定的作用,但并不能引起神经元的损伤。     

小胶质细胞对神经干细胞调控机制的研究进展

脑损伤与神经炎症密切相关,小胶质细胞是这一过程中的关键因素。小胶质细胞可以获得促炎或抗炎的特性,但这如何影响神经干细胞 (NSCs)仍有争议。小胶质细胞在不同的条件下,可以极化为M1型小胶质细胞和M2型小胶质细胞。不同类型的小胶质细胞对NSCs的调控作用不同。但目前关于这方面的研究并未详细阐明具体的作用机制。本文就不同分化类型的小胶质细胞对NSCs调控机制的研究进展进行综述。     

改良的Cajal金升汞染色法显示纤维性星形胶质细胞

目的探索一种快捷、简便、稳定的染色方法显示脑组织内纤维性星形胶质细胞。方法取猫、家兔、大鼠和豚鼠的大脑组织,部分组织采用传统的Cajal金升汞法制片。部分组织采用改良Cajal金升汞法制片。结果与传统Cajal金升汞法比,应用改良Cajal金升汞染色法,缩短了制片时间,纤维性星形胶质细胞染色均匀,结构清晰,胶质细胞纤维显现明显,分枝光滑,较长突起末端膨大的脚板终止于血管壁上。结论应用改良后的Cajal金升汞法染色显示纤维性星形胶质细胞效果明显优于传统Cajal金升汞法。     

间充质干细胞外泌体对海马星形胶质细胞活化的抑制作用研究

目的 探讨间充质干细胞外泌体(MSC-Exo)对海马星形胶质细胞活化的抑制作用.方法 实验通过超速离心法提取脐带MSC-Exo,并使用PKH-26染料标记;MSC-Exo预处理原代海马星形胶质细胞后使用脂多糖(LPS)诱导细胞活化,并分为对照组、LPS组和LPS+MSC-Exo组,进而行免疫细胞化学检测胶质纤维酸性蛋白...     

神经干细胞向少突胶质前体细胞的定向分化诱导

本研究采用神经胶质瘤细胞株(B104 neuroblatoma cells,B104 cells)培养上清(B104CM)和碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF),将冷冻复苏的大鼠胚胎脊髓神经干细胞(neural stem cells,NSCs)定向诱导为少突胶质前体细胞(oligodendrocyte precusor cells,OPCs)。形态学和免疫组化的结果显示,诱导后95％以上的细胞具有双极或多极突起的典型OPCs形态,并表达A285和血小板源生长因子受体-α(platelet derived growth factor receptor-α,PDGFR-α等0PCs标志,所有PDGFR-α阳性的OPCs均不表达β-Tublin Ⅲ,其中仅少量细胞表达胶质原纤维酸性蛋白(glia fibrillary acidic protein,GFAP)。在B104CM和bFGF共存的培养条件下,悬浮培养的OPCs可大量增殖形成少突胶质细胞球,该细胞球可通过传代继续扩增,且扩增的OPCs仍能维持其特有的形态和自我增殖的特性。撤去bFGF和B104CM后,OPCs能进一步分化为成熟的少突胶质细胞(oligodendrocytes,OLs)或Ⅱ型星形胶质细胞。实验表明,诱导NSCs产生的OPCs在形态、增殖以及分化格局等方面均与已报道的存在于胚胎脑区的O-2A前体细胞相类似。该培养系统可为实验性细胞移植的研究提供丰富的细胞来源。     

综述与专论: 星形胶质细胞对神经退行性疾病影响的研究进展

神经退行性疾病是常见且难以治愈的疾病,给患者的生活带来了极大的不便。星形胶质细胞在神经退行性疾病中发挥重要作用。在神经退行性疾病患者神经系统中,受损的神经胶质细胞对周围的神经元可以产生毒性作用,造成神经元功能障碍,从而死亡。同时,受疾病影响产生的一些反应性星形胶质细胞可以保护神经元,清除神经元周围的有害物质,暂缓疾病的恶化。本综述将讨论星形胶质细胞在部分常见神经退行性疾病中发挥的作用,包括肌萎缩侧索硬化（amyotrophic lateral sclerosis,ALS）、阿尔茨海默病（Alzheimer’s disease,AD）和帕金森病（Parkinson’s disease,PD）。同时总结了星形胶质细胞对这些疾病发挥的共同作用,旨在进一步促进神经退行性疾病的研究进展。     

与损伤神经细胞共育后小胶质细胞促进骨髓间充质干细胞神经保护功能

采用原代细胞培养法培养骨髓间充质干细胞(BMMSCs),以鼠小胶质细胞瘤细胞(BV2)和鼠嗜铬细胞瘤细胞(PC12)细胞株分别代替小胶质细胞和神经细胞进行传代培养,应用转移筛网进行BV2与正常或损伤PC12的共育后,考察BV2对BMMSCs的神经保护作用的影响。结果发现小胶质细胞(BV2)与损伤PC12共育后,能促进BMMSCs的神经保护作用,后者的上清液能降低受损PC12的凋亡率(35.9±13.5)%,同对照组(95.1±26.6)%相比差异有统计学意义(P<0.05),且BMMSCs上清液中bFGF升高达到(34.0±10.0)pg/ml,同对照组(20.3±7.1)pg/ml相比二者差异有统计学意义(P<0.05)。     

Discovery of small molecules that enhance astrocyte differentiation in rat fetal neural stem cells

1,3,4-Oxadiazole derivatives were found to enhance astrocyte differentiation in rat fetal neural stem cells (NSCs). Differentiation activity was assessed by immunocytochemistry and analysis of mRNA expression of astrocyte markers, GFAP and S100. Compounds 7 and 8 showed approximately a two-fold increase in astrocyte differentiation without engagement of neuronal differentiation and detectable cytotoxicity.     

Mesenchymal stem cells regulate the proliferation and differentiation of neural stem cells through Notch signaling

The effects of mesenchymal stem cells (MSCs) on proliferation and cell fate determination of neural stem cells (NSCs) have been investigated. NSCs were co-cultured with MSCs or NIH3T3 cells using an in vitro transwell system. After 4 days, immunofluorescence staining showed that the number of cells positive for the cell proliferation antigen, ki-67, in neurospheres in MSCs was greater than in NIH3T3 cells. In some experiments, the top-layers of MSCs and NIH3T3 cells were removed to induce NSCs differentiation. Seven days after initiating differentiation, the levels of the neuronal marker, NSE, were higher in NSCs in MSCs co-culture group, and those of glial fibrillary acidic protein (GFAP) were lower, compared with NIH3T3 cells co-culture group. These were confirmed by immunofluorescence. The role of the Notch signaling pathway analyzed with the specific inhibitor, DAPT, and by examining the expression of Notch-related genes using RT-PCR showed that after co-culturing with MSCs for 24 h, NSCs expressed much higher levels of ki-67, Notch1, and Hes1 than did NSCs co-cultured with NIH3T3 cells. Treatment with DAPT decreased ki-67, Notch1 and Hes1 expression in NCSs, and increased Mash1 expression. The data indicate that the interactions between MSCs and NSCs promote NSCs proliferation and are involved in specifying neuronal fate, mediated in part by Notch signaling.     

Novel bioreactors for the culture and expansion of aggregative neural stem cells

Neural stem cells have been cultured as three-dimensional aggregates in a number of different types of bioreactors. The design and configuration of the bioreactor are shown to be crucial factors for the successful propagation of the cells. A novel bioreactor with liquid re-circulation and a working volume of 200 ml has been designed, tested and shown to be able to produce a higher cell vitality compared to those produced in multi-well plates, shake flasks and stirred flasks. The novel reactor was able to produce a total density of cells of 3.5 x 10(6) cells/ml consisting of a larger number of smaller and proliferative aggregates, compared to only 1.8 x 10(6) cells/ml produced in a multi-well plate. Shake flasks and stirred flasks commonly used for facilitating mass transfer in the culture of micro-organisms are shown to be unsuitable for the propagation of neural stem cells.     

人胚胎神经干细胞的基础及应用研究进展

神经干细胞是中枢神经系统中具有增殖、自我更新能力以及多种分化潜能的细胞,对它的研究已经成为神经生物学、发育生物学以及脑科学研究的一个热点。随着神经干细胞（特别是胚胎神经干细胞）的分离、培养成功,神经干细胞移植已被尝试用于神经系统损伤等疾病的治疗。但是,关于胚胎神经干细胞的研究尚处于初级阶段,特别是人胚胎神经干细胞的研究、报道还比较少。本文对国内、外近几年来关于人胚胎神经干细胞的基础及应用研究进展作了综述。     

锂对造血干细胞和神经干细胞作用影响的研究进展

锂在现代精神病学中使用超过65年,其构成了双相情感障碍（BD）长期治疗的基础。锂的许多生物学特性已经被证实,包括抗病毒、血液系统和神经系统保护作用。本文系统综述了锂对造血干细胞（HSCs）、神经干细胞（NSCs）以及诱导多能干细胞（iPSCs）作用影响的研究进展及其目前已证实的分子机制。自20世纪70年代以来,锂对保持HSCs和生长因子高水平的作用已被报道。锂可以改善HSCs的归巢能力、形成菌落的能力和自我更新的能力。关于锂对神经发生影响的研究表明,锂可促进海马齿状回的干细胞增殖,并导致施旺氏细胞有丝分裂活性增强。锂被证实与神经保护和神经营养作用相关,具体作用反映在锂可改善突触的可塑性,促进细胞存活,抑制细胞凋亡等。在临床研究中发现,锂离子的治疗可增加大脑灰质的成分,尤其作用在额叶、海马和杏仁核等位置。锂对干细胞的作用涉及多条介质和信号通路,其中最重要的介质和信号通路被认为是糖原合成酶激酶-3（GSK-3）和Wnt/β-catenin通路,另外包括调节cAMP、蛋白激酶B、磷脂酰肌醇3-激酶（pi3k）和肌醇单磷酸酶（IMP）水平的信号通路等也与锂作用有紧密的联系。锂在现阶段被利用于治疗BD和降低痴呆症患病风险的临床实验中,并对神经退行性疾病发挥有益作用。除此之外,为了研究的发病机制和锂离子在其中的作用机制,从BD患者中获得的iPSCs也被广泛应用。     

Wnt proteins promote neuronal differentiation in neural stem cell culture

Wnt signaling is implicated in the control of cell growth and differentiation during CNS development from studies of mouse and chick models, but its action at the cellular level has been poorly understand. In this study, we examine the in vitro function of Wnt signaling in embryonic neural stem cells, dissociated from neurospheres derived from E11.5 mouse telencephalon. Conditioned media containing active Wnt-3a proteins are added to the neural stem cells and its effect on regeneration of neurospheres and differentiation into neuronal and glial cells was examined. Wnt-3a proteins inhibit regeneration of neurospheres, but promote differentiation into MAP2-positive neuronal cells. Wnt-3a proteins also increase the number of GFAP-positive astrocytes but suppress the number of oligodendroglial lineage cells expressing PDGFR or O4. These results indicate that Wnt-3a signaling can inhibit the maintenance of neural stem cells, but rather promote the differentiation of neural stem cells into several cell lineages.     

Differentiation of rhesus embryonic stem cells to neural progenitors and neurons

Embryonic stem (ES) cells are pluripotent cells capable of differentiating into cell lineages derived from all primary germ layers including neural cells. In this study we describe an efficient method for differentiating rhesus monkey ES cells to neural lineages and the subsequent isolation of an enriched population of Nestin and Musashi positive neural progenitor (NP) cells. Upon differentiation, these cells exhibit electrophysiological characteristics resembling cultured primary neurons. Embryoid bodies (EBs) were formed in ES growth medium supplemented with 50% MEDII. After 7 days in suspension culture, EBs were transferred to adherent culture and either differentiated in serum containing medium or expanded in serum free medium. Immunocytochemistry on differentiating cells derived from EBs revealed large networks of MAP-2 and NF200 positive neurons. DAPI staining showed that the center of the MEDII-treated EBs was filled with rosettes. NPs isolated from adherent EB cultures expanded in serum free medium were passaged and maintained in an undifferentiated state by culture in serum free N2 with 50% MEDII and bFGF. Differentiating neurons derived from NPs fired action potentials in response to depolarizing current injection and expressed functional ionotropic receptors for the neurotransmitters glutamate and gamma-aminobutyric acid (GABA). NPs derived in this way could serve as models for cellular replacement therapy in primate models of neurodegenerative disease, a source of neural cells for toxicity and drug testing, and as a model of the developing primate nervous system.     

Suspension culture of hematopoietic stem cells in stirred bioreactors

Hematopoietic stem cells have applications in bone marrow transplantations for the treatment of hematopoietic disorders. When murine hematopoietic stem cells were cultured in 50 ml stirred bioreactors for 14 d, stem-cell-antigen-1 positive cells (hematopoietic primitive progenitor cells) and long-term culture-initiating cells (hematopoietic stem cells) grew by 5-fold and 4-fold, respectively. These results show the possibility of growing hematopoietic stem cells using a stirred bioreactor.