Development of neural precursor cells from mouse embryonic stem cells

Embryonicstemcells(EScells)arederivedfromtotipotentcellsofearlyembryoandpossessunlimited,undifferentiatedproliferationinvitro[1].EScellshavetheinherentcapacityofdifferentiatingintoallcelltypesofthenervoussystemasdemonstratedbytheex-perimentthatchimericmicewereformedfromem-bryosinwhichEScellsaretransplantedintotheinnercellmass[2].ThesuccessfulestablishmentofhumanEScelllineindicatedprofoundimplicationthatEScellsmayprovideavirtuallyunlimiteddonorsourcefortransplantation[3]. Threepaperspublish…     

体外诱导人胚胎干细胞定向分化为神经干细胞

目的:探讨体外定向诱导人胚胎干细胞(human embryonic stem cells,hESCs)生成高纯度神经干细胞(neural stem cells,NSCs)的方法.方法:模拟体内神经细胞分化发育的不同阶段及微环境,分三阶段诱导hESCs定向生成NSCs.形态学观察结合免疫荧光细胞化学、流式细胞术和RT-PCR检测胚胎干细胞标志和神经干细胞标志;NSCs分化实验对所诱导的NSCs的分化潜能进行检测.结果:体外培养的hESCs在胚胎成纤维细胞饲养层上连续传代培养50代,仍保持SSEA-4,TRA-1-81阳性,表达Nanog基因,流式细胞术检测SSEA-4阳性表达率为83.44%;经三步法最终可诱导形成纯度高达90%以上的nestin阳性细胞,表达nestin基因,流式细胞术检测nestin阳性表达率为89.38%;诱导生成的细胞反复传代,仍表现为nestin阳性,并可进一步分化为神经元、星形神经胶质细胞和少突胶质细胞.结论:模拟体内神经分化过程的三步诱导法,可诱导hESCs生成较高纯度的NSCs,并能较好维持其干细胞特性和具有进一步分化的能力.     

星形胶质细胞诱导神经干细胞定向分化试验研究

目的 研究新生SD大鼠星形胶质细胞培养上清液对神经干细胞(neural stem cells，NSCS)体外定向分化的影响，探讨神经干细胞分化条件。方法 收集新生和成年SD大鼠星形胶质细胞培养的上清液，以1：3比例同DMEM／F12培基混合，分别对胎鼠来源的神经干细胞进行诱导分化，倒置相差显微境下观察细胞的生长情况。并采用免疫荧光检测方法对分化细胞鉴定和计数。结果 新生鼠星形胶质细胞培养上清液与DMEM／F12的混合培基诱导神经干细胞分化为神经元的比例明显提高。结论 新生鼠星形神经胶质细胞能促使神经干细胞向神经元方向分化。     

小鼠胚胎干细胞定向分化为神经细胞的研究进展

小鼠胚胎干细胞（embryonic stem cell,ES cell）体外培养可以分化成为外胚层组织,并进一步分化为神经元和神经胶质细胞。这些细胞已用于中枢神经系统疾病的细胞替代治疗和治疗药物的研发。小鼠胚胎干细胞定向分化为神经细胞的方法主要有拟胚体介导的神经细胞分化、基质细胞诱导的神经细胞分化、默认模式介导的神经细胞分化、单层粘附培养诱导的神经细胞分化和遗传工程介导的神经细胞分化等。本文综述了这些分化方法。     

体外直接诱导人胚胎干细胞向神经细胞分化的研究

目的探讨体外直接诱导HSF6人胚胎干细胞(humanem bryonic stem cells,hESCs)分化为神经细胞的方法。方法采用直接的方法,在1%血清培养条件下,顺序添加bFGF、RA和Forskolin,诱导HSF6人ESCs分化为神经细胞。结果细胞发生神经样形态学改变,免疫荧光细胞化学分析结果显示,分化细胞表达神经干细胞特异性标志分子——巢蛋白(nestin),以及神经元标志分子——β微管蛋白Ⅲ(neuron-specific class Ⅲ beta-tubulin,TuJ1)。实验组nestin阳性细胞数占(95.2±3.03)%,明显高于未添加诱导因子组的(31.6±4.93)%,差异有统计学意义(P<0.05)。结论本研究直接诱导hESCs分化为神经细胞,减少了常规经胚胎体(embryoid body,EB)的诱导方法而产生其它胚层细胞的机会,为进一步探索hESCs源性神经细胞的功能,以及为细胞替代治疗提供高纯度的hESCs源性神经细胞奠定了基础。     

小鼠胚胎干细胞体外分化为神经前体细胞的研究

目的 探索小鼠胚胎干细胞（Embryonic stem cell,ES cell）体外分化为神经前体细胞（Neural precursor cells,NPC）的无血清培养条件,比较人胚胎成纤维细胞（Human embryonic fibroblasts,HEF）与小鼠胚胎成纤维细胞（Mouse embryonic fibroblasts,MEF）对小鼠ES细胞生长的作用。方法 在MEF或HEF饲养层上培养ES细胞,培养液中含白血病抑制因子。采用无血清方法培养NPC,免疫组化方法检测巢蛋白（Nestin）,用硝基四氮啖蓝/5-溴-4-氯-吲哚基磷酸（NBT/BCIP）显色检测碱性磷酸酶。结果 无血清培养可以获得86%的NPC。HEF与MEF-样能维持ES未分化状态。结论 无血清培养方法有利于ES细胞向NPC分化,HEF可用于小鼠ES细胞的培养,而且比MEF优越。     

An improved method for directional differentiation and efficient production of neurons from embryonic stem cells in vitro

Summary To establish a method of directional differentiation and efficient production of neurons from embryonic stem cells (ES cells)in vitro, based on the 4-/4+ protocol described by Bain, a new method was established to induce ES cells differentiating into neurons by means of three-step differentiation using all-trans retinoic acid (ATRA) combined with astrocyte-conditioned medium (ACM)in Vitro. The totipotency of ES cells was identified by observation of cells morphology and formations of teratoma in immunocompromised mice. The cells differentiation was evaluated continuously by the detection of the specific cellular markers of neural stem cells, neurons and astrocytes, including nestin, NSE and GFAP using immunohistochemistry assay. The NSE positive cells' ratio of the differentiated cells was determined by flow cytometry. It was found that the transparent circular clusters surrounding embryoid bodies induced with combining induction protocol formed just after 24 h and gradually enlarged later. This phenomenon could not be observed in EBs induced only by ATRA. The NSE positive cells' ratio in the cells induced with ATRA and ACM was higher than that of the cells induced by ATRA at different time points of differentiation, and finally reached up to 73.5% among the total differentiated population. It was concluded that ES cells could be induced into neurons with high purity and yield by means of inducing method combining with ATRA and ACM. ZHOU Yufeng, male, born in 1974, Doctor in Charge     

胚胎干细胞定向分化为神经细胞的研究进展

最近研究表明胚胎干细胞(embryonic stem cells，ESC)在体内外均可以发育分化出神经组织细胞，这对于了解神经发育的机制和研究神经组织退化性或者脑组织损伤性疾病的治疗具有重要的意义。本文就胚胎干细胞定向分化为神经组织细胞及其基因表达特点作一综述。     

胚胎大鼠纹状体区神经干细胞的体外培养

目的探讨胚胎大鼠纹状体区神经干细胞的培养、分化和鉴定技术。方法从胚胎大鼠纹状体区分离神经干细胞,用无血清培养技术进行体外原代培养、传代,加血清进行诱导分化。荧光免疫染色技术进行鉴定。结果从胚胎大鼠纹状体区分离出神经干细胞,并可分化为神经元、星形胶质细胞和少突胶质细胞。结论采用该体外培养技术分离的纹状体区神经干细胞可在体外大量增殖,并有多向分化潜能。     

不同方法诱导小鼠胚胎成纤维细胞直接转化为神经干细胞效率的比较

目的 比较不同方法诱导小鼠胚胎成纤维细胞（mouse embryonic fibroblasts, MEFs）直接转化为诱导型神经干细胞(induced neural stem cells, iNSCs)的效率,以进一步优化诱导方法。方法 构建慢病毒表达载体pLenti6.3-Sox2-IRES2-EGFP,分别采用单转录因子Sox2、小分子物质、转录因子Sox2联合小分子物质共同作用三种方法将MEFs直接转化为iNSCs。qPCR检测神经干细胞的标志基因和多潜能标志基因的表达。免疫荧光检测神经干细胞的标记物nestin,计算iNSCs的转染效率。iNSCs在分化培养基中贴壁培养7~14d,免疫荧光分别检测神经元、星形胶质细胞和少突胶质细胞的细胞标记物MAP2、GFAP和Olig2的表达。结果 诱导后4~6d,MEFs的形态发生明显改变。免疫荧光显微镜下的结果显示诱导因子Sox2加小分子的诱导方法较单独使用Sox2和单独使用小分子物质进行诱导的效率高,差异具有统计学意义（P<0.05）。qPCR的结果证明,3组iNSCs多种神经干细胞的标志基因（Sox2、nestin、Blbp、Pax6）的表达均较MEFs明显增高,3组间差异无统计学意义（P>0.05）;共聚焦显微镜的结果证明3种方法诱导的iNSCs具有分化为神经元、星形胶质细胞、少突胶质细胞的能力,3组间差异无统计学意义（P>0.05）。结论 转录因子Sox2联合小分子共同作用可显著提高MEFs转化为iNSCs的效率且并不改变iNSCs的细胞功能特点。3组的iNSCs均具有神经干细胞自我增殖和多向分化的能力。     

Mouse A6-positive Hepatic Oval Cells Derived from Embryonic Stem Cells简

Summary： Oval cells have a potential to differentiate into a variety of cell lineages including hepatocytes and biliary epithelia. Several models have been established to activate the oval cells by incorporating a variety of toxins and carcinogens, alone or combined with surgical treatment. Those models are obviously not suitable for the study on human hepatic oval cells. It is necessary to establish a new and efficient model to study the human hepatic oval cells. In this study, the hepatocyte growth factor（HGF） and epidermal growth factor（EGF） were used to induce differentiation of mouse embryonic stem（ES） cells into hepatic oval cells. We first confirmed that hepatic oval cells derived from ES cells, which are bipotential, do exist during the course of mouse ES cells＇ differentiation into hepatic parenchymal cells. RT-PCR and transmission electron microscopy were applied in this study. The ratio of Sca-1＋/CD34＋ cells sorted by FACS in the induction group was increased from day 4 and reached the maximum on the day 8, whereas that in the control group remained at a low level. The differentiation ratio of Sca-1＋/CD34＋ cells in the induction group was significantly higher than that in the control group. About 92.48% of the sorted Sca-1＋/CD34＋ cells on the day 8 were A6 positive. Highly purified A6＋/Sca-1＋/CD34＋ hepatic oval cells derived from ES cells could be obtained by FACS. The differentiation ratio of hepatic oval cells in the induction group（up to 4.46%） was significantly higher than that in the control group. The number of hepatic oval cells could be increased significantly by HGF and EGF. The study also examined the ultrastructures of ES-derived hepatic oval cells＇ membrane surface by atomic force microscopy. The ES-derived hepatic oval cells cultured and sorted by our protocols may be available for the future clinical application.     

Expansive effects of aorta-gonad-mesonephros-derived stromal cells on hematopoietic stem cells from embryonic stem cells

Background Hematopoietic stem cells (HSCs) give rise to all blood and immune cells and are used in clinical transplantation protocols to treat a wide variety of refractory diseases, but the amplification of HSCs has been difficult to achieve in vitro. In the present study, the expansive effects of aorta-gonad-mesonephros (AGM) region derived stromal cells on HSCs were explored, attempting to improve the efficiency of HSC transplantation in clinical practice.Methods The murine stromal cells were isolated from the AGM region of 12 days postcoitum (dpc) murine embryos and bone marrow（BM）of 6 weeks old mice, respectively. After identification with flow cytometry and immunocytochemistry, the stromal cells were co-cultured with ESCs-derived, cytokines-induced HSCs. The maintenance and expansion of ESCs-derived HSCs were evaluated by detecting the population of CD34+ and CD34+Sca-1+cells with flow cytometry and the blast colony-forming cells (BL-CFCs), high proliferative potential colony-forming cells (HPP-CFCs) by using semi-solid medium colonial culture. Finally, the homing and hematopoietic reconstruction abilities of HSCs were evaluated using a murine model of HSC transplantation in vivo.Results AGM and BM-derived stromal cells were morphologically and phenotypically similar, and had the features of stromal cells. When co-cultured with AGM or BM stromal cells, more primitive progenitor cells (HPP-CFCs ) could be detected in ESCs derived hematopoietic precursor cells, but BL-CFC’s expansion could be detected only when co-cultured with AGM-derived stromal cells. The population of CD34+ hematopoietic stem/progenitor cells were expanded 3 times,but no significant expansion in the population of CD34+Sca-1+ cells was noted when co-cultured with BM stromal cells. While both CD34+ hematopoietic stem/progenitor cells and CD34+Sca-1+ cells were expanded 4 to 5 times respectively when co-cultured with AGM stromal cells. AGM region-derived stromal cells, like BM-derived stromal cells, could promote hematopoietic reconstruction and HSCs’ homing to BM in vivo.Conclusions AGM-derived stromal cells in comparison with the BM-derived stromal cells could not only support the expansion of HSCs but also maintain the self-renewal and multi-lineage differentiation more effectively. They are promising in HSC transplantation. Chin Med J 2005; 118(23):1979-1986     

C57胚胎小鼠神经干细胞的分离、培养与鉴定

目的体外分离、培养神经干细胞（NSCs）,并对其进行鉴定。方法采用手动法及胰蛋白酶消化法分离胎鼠脑细胞,用优化的无血清NSCs培养基进行培养。细胞免疫荧光法检测NSCs特异性标记分子的表达。结果分离的脑细胞体外培养48 h已大部分贴壁,3 d左右获得大量未分化呈巢状悬浮生长的神经干细胞团。第3代时,很少见到贴壁细胞,几乎全是神经球,神经球周围存在较多微刺。细胞表达一种中间丝蛋白,即巢蛋白（nestin）。结论成功分离、鉴定出C57小鼠NSCs,并可在体外条件下进行传代扩增培养。     

丙泊酚对大鼠胚胎神经干细胞增殖及分化的影响

目的探讨丙泊酚对体外培养大鼠胚胎神经干细胞(NSCs)增殖及分化的影响。方法采用孕14～16 d Wistar大鼠,进行NSCs原代培养并用Nestin鉴定,按以下给药分成六组:空白对照组(control)、脂肪乳对照组(introlipid)、丙泊酚不同浓度组[5、25、50、100μmol/l],用5-溴脱氧尿(Brdu)掺入法观察丙泊酚对胚胎神经干细胞增殖的影响。胚胎神经干细胞诱导分化过程中加入50μmol/l丙泊酚,采用NeuN、GFAP免疫组化法观察丙泊酚对胚胎神经干细胞分化的影响。结果分离培养的神经干细胞95%以上呈Nestin阳性,不同浓度丙泊酚组Brdu阳性细胞百分数没有差异,丙泊酚NeuN阳性细胞百分数(23.1±0.9%)明显高于对照组(13.4±0.8%)(P<0.05),而GFAP细胞阳性细胞数与对照组相比没有明显差异。结论临床相关剂量丙泊酚对体外培养大鼠神经干细胞增殖没有影响,但能诱导神经干细胞向神经元细胞分化。     

低氧对小鼠胚胎干细胞诱导分化成心肌细胞的影响

目的探讨在胚胎干细胞诱导分化过程的不同阶段进行低氧处理对分化心肌细胞的影响。方法建立胚胎干细胞向心肌细胞诱导分化的实验方法,在分化过程的不同阶段采取低氧（氧浓度为4%）处理,并设立常氧组（约为20%）作为对照,用免疫荧光鉴定分化后的心肌细胞,以流式细胞术检测低氧对分化心肌细胞的增殖、分化、凋亡的影响。结果分化细胞经免疫荧光检测显示,部分细胞呈α辅肌动蛋白阳性（红色）、心肌肌钙蛋白I阳性（绿色）;分化细胞经流式检测显示,与常氧组相比,悬滴低氧组α-actinin阳性细胞和cTnI阳性细胞的比率分别提高了12.55%（P〈0.01）和6.11%（P〈0.05）,悬浮低氧组凋亡比率与常氧组相比明显提高（P〈0.01）,悬滴低氧组处于S期的细胞比率与常氧组相比明显降低（P〈0.01）。结论在胚胎干细胞向心肌细胞的定向诱导分化过程中,采用悬滴阶段低氧处理,使心肌特异性蛋白阳性细胞比率提高,细胞凋亡率稳定,细胞增殖能力因细胞分化成熟而有所降低,为低氧处理的最佳方案。     

Histone deacetylase inhibitor promotes differentiation of embryonic stem cells into neural cells in adherent monoculture

Background Embryonic stem （ES） cells poss unlimited self-renewal capacity and the ability to differentiate into cell of all three germ layers in vitro. Induced differentiation of ES cells to neural lineage cells has great potential in basic study of neurogenesis and regeneration therapy of neurodegenerative diseases. Histone deacetylase （HDAC） inhibitors enhance histone acetylation so that globularly activate gene expression and may initiate multilineage differentiation. In this study,we aimed to develop a method to induce the differentiation of ES cells to neural cells combining HDAC inhibition and neural cellselection.Methods In this study, we used HDAC inhibitor sodium butyrate （NAB） to induce the differentiation of mouse embryonic stem cells to neural cells through monolayer culture. After differentiation initiation by histone deacetylase inhibitor sodium butyrate, neural cells were induced and selected with a serum free culture system. Results Homogeneous neurons without glial cells demonstrated by molecular marker expression were differentiated with the method. The resultant neurons were excitable. Conclusion The method combined differentiation induction effect of HDAC inhibitors and selective culture system to derive neural cells from ES cells, and implied the involvement of epigenetic regulation in neural differentiation.     

胚胎大鼠神经干细胞的培养及鉴定

目的：探讨胚胎大鼠神经干细胞培养，传及鉴定方法。方法：从胚胎大鼠脑室下区（SVZ）组织分离得到神经干细胞，采用无血清培养技术进行培养，并诱导分化，采用SABC法对分化后后的细胞进行神经元特异性烯醇化酶（NSE）、胶质纤维酸蛋白（GFAP）检测及姬姆萨染色进行细胞鉴定。结果：成功培养出了胚胎大鼠神经干细胞，培养出的细胞具有自我更新能力的增殖能力，可分化为神经元，神经胶质细胞及少突胶质细胞，结论：胚胎大鼠神经干细胞在体外适宜的培养条件下具有自我更新，增殖和多向分化潜能。     

小鼠胚胎神经干细胞海马移植对APP/PS1双转基因AD小鼠的治疗作用

目的 在APP/PS1双转基因阿尔茨海默病(Alzheimer disease, AD)小鼠观察神经干细胞(nerual stem cells, NSCs)移植后细胞的存活、迁移以及对小鼠记忆功能的影响.方法 增强型绿色荧光蛋白(enhanced green fluorescent protein, EGFP)质粒转染培养胚胎NSCs,小鼠海马内移植,水迷宫实验检测小鼠认知功能.结果 EGFP转染NSCs海马内移植2个月后可观察到GFP阳性细胞,大部分分布在针道附近,部分向同侧皮层迁移,亦有部分通过胼胝体向对侧大脑迁移,同时小量细胞发出类似于神经元的长突起.AD小鼠的记忆功能明显改善.结论 胚胎NSCs海马内移植后能存活、迁移并分化为神经组织细胞,并能显著改善APP/PS1双转基因AD小鼠的认知功能障碍.     

纤维连接蛋白在小鼠胚胎干细胞诱导为神经前体细胞中的作用

目的 观察采用ITSF和N2无血清培养基诱导小鼠胚胎干细胞为神经前体细胞的作用及纤维连接蛋白对神经诱导的影响。方法 小鼠胚胎干细胞的培养和无血清诱导为神经有体细胞，NBT／BCIP染色，Nestin免疫组化染色。结果 细菌培养皿法或悬滴法培养胚体，ITSF或N2无血清培养基均能将小鼠胚胎干细胞诱导为神经前体细胞。纤维连接蛋白预处理培养皿法表面，对胚体的贴壁情况影响不大，但能使无血清培养后存活的细胞增多。结论 小鼠胚胎干细胞在ITSF和N2培养基均能分化为神经前体细胞，在N2培养基中加入纤维连接有使存活的神经前体细胞数量增多。