神经干细胞与脑胶质瘤干细胞☆

所有的肿瘤组织并不是由均一的肿瘤细胞所组成的,不同的细胞具有不同的增殖、浸润和转移能力,亦即肿瘤的异质性。其中存在少数担当着干细胞角色的肿瘤细胞,具有干细胞的基本特性,包括自我更新能力、无限的增殖能力和多向分化潜能,为肿瘤干细胞。神经干细胞具有很强的自我更新机制,获得较少突变即有可能恶性转化,而且干细胞存活时间较长,这意味着干细胞比成熟细胞发生细胞复制的错误几率更大,因外界环境的刺激而发生突变的机会更多,最终形成脑胶质瘤干细胞,同时调节神经干细胞增殖和自我更新的基因在脑胶质瘤的脑胶质瘤干细胞中也表达,这也是支持神经干细胞是脑胶质瘤干细胞来源的;也有推测认为它可能起源于已分化的细胞,由这些细胞突变发生去分化得来,并通过基因突变而获得了干细胞自我更新的特性,从而形成脑胶质瘤干细胞。通过探讨神经干细胞与脑胶质瘤干细胞,为脑胶质瘤的治疗提供依据。     

Quite amusing stem cells:Muse cells

<正>Stem cells may be the future of therapeutics for stroke due to their regenerative and immunomodulatory capabilities.Major barriers faced when employing stem cells,however,include faulty migration,low cell survival,and diminished proliferation.M ultilineage-differentiating stress ensuring (Muse) cells,a subset of mesenchymal stem cells,overcome these barriers.Muse cells aid in neuroregeneration,have immense regenerative potential,and are pluripotent,non-tumorigenic,and immunomodulatory.I...     

Oligodendroglioma-like cells (clear cells) in ependymoma

A brain tumor of a 22-year-old man was composed mostly of round cells with perinuclear halos (clear cells), forming clusters intersected by small blood vessels. In some areas, the tumor cells showed perivascular arrangement and epithelial pattern. Phosphotungstic-acid hematoxylin stain and immunoperoxidase stain for glial fibrillary acidic protein (GFAP) technique failed to stain the clear cells. Electron microscopy of the clear cells revealed them to be classical ependymoma cells with well developed intercellular junctions, microvilli and cilia. As no reporters in the past showed the evidence to clarify the nature of the clear cells, this case is considered a good example to support the viewpoint that the clear cells (oligodendroglioma-like cells) commonly observed in ependymomas are in reality ependymoma cells. It is stressed that the diagnosis of "mixed glioma" or "oligoependymoma" should be made with sufficient caution despite the recent advances of GFAP technique.     

神经干细胞诱导骨髓基质细胞向神经元样细胞分化

目的：研究骨髓基质细胞向神经元样细胞分化的条件。方法：神经十细胞诱导骨髓基质细胞向神经元样细胞分化，免疫细胞化学方法对分化的和未分化的细胞进行鉴定。结果：神经于细胞可诱导骨髓基质细胞向神经元样细胞分化，分化的细胞表达神经元的标志物神经元特异性烯醇化酶(NSE)。结论：骨髓组织中存在能分化为神经元的于细胞，可能成为中枢神经系统自体移植的于细胞的来源。     

Transplanted human bone marrow cells generate new brain cells

Multiple studies have reported that adult cells of bone marrow origin can differentiate into muscle, skin, liver, lung, epithelial cells, and neurons. To determine whether such cells might produce neurons and other cells in the human brain, we examined paraffin sections from female patients who had received bone marrow transplants from male donors. Y-chromosomes were labeled using autoradiography and fluorescent in situ hybridization. Neurons and astrocytes were identified histologically and immunohistochemically in neocortex, hippocampus, striatum, and cerebellum. However, most labeled cells in both gray and white matter appeared to be glia. Others have suggested that such Y-labeling represents fusion between host and donor cells, rather than true transdifferentiation. The possibilities of fusion and microchimerism were therefore examined using buccal epithelial cells as a model system. The female patients in this study had received either bone marrow or stem cell (CD34+ enriched) transplants from their brothers. Double labeling for X- and Y-chromosomes showed that Y-labeled buccal cells could not be explained by fusion. Genotyping studies of one patient, her brother, and her son ruled out the possibility of microchimerism. Whether, and under what circumstances, some form of bone marrow transplantation might provide adequate number of cells capable of replacing lost brain cells or enhancing their function will require additional studies.     

Differentiation of radial glia-like cells from embryonic stem cells

Radial glial cells play important roles in neural development. They provide support and guidance for neuronal migration and give rise to neurons and glia. In vitro, neurons, astrocytes, and oligodendrocytes can be generated from neural and embryonic stem cells, but the generation of radial glial cells from these stem cells has not yet been reported. Since the differentiation of radial glial cells is indispensable during brain development, we hypothesize that stem cells also generate radial glial cells during in vitro neural differentiation. To test this hypothesis, we utilized five different clones of mouse embryonic (ES) and embryonal carcinoma (EC) stem cell lines to investigate the differentiation of radial glial cells during in vitro neural differentiation. Here, we demonstrate that radial glia-like cells can be generated from ES/EC cell lines. These ES/EC cell-derived radial glia-like cells are similar in morphology to radial glial cells in vivo, i.e., they are bipolar with an unbranched long process and a short process. They also express several cytoskeletal markers, such as nestin, RC2, and/or GFAP, that are characteristics of radial glial cells in vivo. The processes of these in vitro generated radial glia-like cells are organized into parallel arrays that resemble the radial glial scaffolds in neocortical development. Since radial glia-like cells were observed in all five clones of ES/EC cells tested, we suggest that the differentiation of radial glial cells may be a common pathway during in vitro neural differentiation of ES cells. This novel in vitro model system should facilitate the investigation of regulation of radial glial cell differentiation and its biological function.     

The tropism of embryoid body cells for glioma cells

It has been demonstrated that several types of adult stem cells have a common attribute of tropism for gliomas. In our study, we provided evidence that embryonic stem cell-derived embryoid body (EB) cells also exhibited a tropism for gliomas. Chemotaxis assays and organotypic hippocampal slice culture experiments showed that EB cells were attracted by the conditioned medium from C6 glioma cells and by C6 glioma cells deposited on the slice. Aggregate culture assays showed that EB cells could coaggregate with C6 glioma cells. Embryoid body cells injected intratumorally were found to distribute throughout the tumor mass. All data indicated that EB cells displayed a tropism for gliomas.     

Astroglial cells: glucocorticoid target cells in the brain

Glutamine synthetase (GS), an enzyme localized in astroglial cells in the brain, is directly implicated in brain detoxification. An ontogenic study of GS activity was performed in homogenates from four distinct brain areas in comparison with the respective astrocytes obtained in primary cultures. GS was induced by hydrocortisone in the astrocytes of all brain areas studied; only cerebellum and cerebral hemisphere astroglial cells had a higher specific activity when compared with the corresponding homogenates. N6O2-Dibutyryl adenosine 3',5'-cyclic monophosphate (dBc AMP), insulin, soluble brain factors, and noradrenaline (NA) were also able to modulate GS activity. Brain factors as well as dBc AMP interfered with hydrocortisone induction of GS. Regulation by hydrocortisone paralleled the variation in its concentration in brain during development. We conclude that astroglial cells are target cells for glucocorticoids, which may modulate ammonia detoxification in these cells.     

Dipping cells in acidic bath could make stem cells

<正>The discovery that somatic mammalian cells can be epigenetically reprogrammed to induced pluripotent stem cells(iPSCs)through the exogenous expression of the Oct4,Sox2,Klf4 and c-Myc(OSKM)has demonstrated a new way for cell-replacement therapy in regenerative medicine(Li et al.,2013;Nishimura     

脂肪来源干细胞诱导表皮细胞化的研究现状与进展

背景：脂肪干细胞通过向表皮细胞进行诱导可以对难愈创面的修复提供理想的解决方法。 目的：通过分析总结近10年以来脂肪干细胞的研究方法和思路,期待能为脂肪干细胞诱导表皮细胞化提供总结和探索。 方法：由第一作者分别以“干细胞、脂肪干细胞”、“ADSCs 、adipose derived stem cells” 为检索词,应用计算机检索重庆维普(VIP)期刊全文数据库以及万方数据库2001-01/2010-10有关文章,纳入有关脂肪干细胞组织工程的文献。排除与研究目的无关和内容重复者。保留26篇文献做进一步分析。 结果及结论：脂肪干细胞作为一种种子细胞,有望在一定的条件下定向诱导分化成为表皮细胞,并且提高诱导分化率和扩增能力,最终达到临床治疗使用的目的。其具有的来源丰富、易于获得、有多向分化潜能、相容性好、对患者损伤小等特点无疑是其他众多间充质干细胞所无法比拟的。但同时,脂肪干细胞在无免疫力的移植受体上表现的肿瘤样无限增生特性,在进入临床试验前仍需要寻找并建立合适的动物模型进行长期观测以确定其移植后的安全性;其次,脂肪干细胞向表皮细胞诱导尚无一安全稳定并行之有效的培养、诱导方式;以及在批量提取生产脂肪干细胞的过程中,如何保障细胞质量的均一稳定性仍然有待进一步研究。     

间充质干细胞向肝样细胞的诱导分化

目前很多体内外实验都已表明间充质干细胞具有向肝样细胞或肝细胞分化的能力,这使间充质干细胞治疗肝脏疾病成为可能。 目的：总结和分析间充质干细胞向肝样细胞诱导分化的方法、机制以及存在的问题。 方法：应用计算机检索PubMed数据库(2000-01/2009-12),以“mesenchymal stem cells,hepatocyte, differentiation”为检索词;应用计算机检索维普数据库(2000-01/2009-12),以“间充质干细胞,肝细胞,诱导分化”为检索词。选择文章内容与间充质干细胞诱导分化为肝细胞相关,同一领域文献则选择近期发表或发表在权威杂志文章。 结果与结论：共收集146篇关于间充质干细胞向肝样细胞诱导分化的文章,纳入 31篇符合标准的文献。间充质干细胞可在体外及肝脏病理条件下分化为肝细胞,其作用机制主要是间充质干细胞在合适的细胞因子组合诱导下,细胞因子通过特定的细胞信号传导途径,作用于细胞核,启动或关闭相应的基因,表达特异的蛋白质,使间充质干细胞向肝细胞分化。随着研究不断得深入,这使间充质干细胞治疗肝脏疾病成为可能,但其研究有待进一步完善。     

Differentiation of human neural stem cells into retinal cells

We have previously reported that transplanted human neural stem cells (HNSCs) display extensive migration and positional incorporation into the aged rat brain, which is associated with an improvement in cognitive function. In the current study, to investigate whether HNSCs are capable of differentiating into retinal cells, we treated HNSCs with human transforming growth factor-beta3 (TGF-beta3) under a serum-free differentiation condition. After 5 days of differentiation in vitro we detected opsin-immunopositive cells in the culture treated with TGF-beta3. We also transplanted TGF-beta3-treated HNSCs into the rat vitreous cavity. The donor cells migrated and differentiated into opsin-positive cells in the host retinal cell layer. Here we show for the first time that TGF-beta3-treated HNSCs differentiate into retinal cells.     

Large-scale analysis of neural stem cells and progenitor cells

The past few years have seen remarkable progress in our understanding of stem cell biology. The wealth of genomic data and the multiplicity of sources have enabled researchers to begin to profile stem cells in detail. In this paper we describe the biological and technical controls necessary to obtain reliable data and the relative merits of various large-scale analytical techniques including microarray, expressed sequence tag enumeration, serial analysis of gene expression and massively parallel signature sequencing. We suggest that while much has been learned, additional information remains to be gleaned by meta-analysis of existing data.     

In vitro differentiation of adipose-derived stem cells and bone marrow-derived stromal stem cells into neuronal-like cells

Adipose-derived stem cells and bone marrow-derived stromal stem cells were co-cultured with untreated or Aβ1-40-treated PC12 cells, or grown in supernatant derived from untreated or Aβ1-40-treated PC12 cells. Analysis by western blot and quantitative real-time PCR showed that protein levels of Nanog, Oct4, and Sox2, and mRNA levels of miR/125a/3p were decreased, while expression of insulin-like growth factor-2 and neuron specific enolase was increased. In comparison, the generation of neuron specific enolas...     

诱导成人骨髓基质细胞成为神经干细胞及其分化的实验研究

目的　体外诱导成人骨髓基质细胞 (BMSCs)转化为神经干细胞 (NSCs)进而分化为神经元和胶质细胞。方法　以含有碱性成纤维细胞生长因子 (b FGF)或表皮生长因子 (EGF)加 b FGF或 b FGF、EGF加全反式维甲酸 (ATRA)的培养液培养 BMSCs,进行显微镜观察 ,纤维连接蛋白 (fibronectin)、I型胶原 (collagen )和神经上皮干细胞蛋白 (nestin)免疫组织化学染色和神经元特异烯醇化酶 (NSE) ,胶质纤维酸性蛋白 (GFAP)免疫荧光染色。结果　经诱导物诱导 72 h后 ,fibronectin和 collagen I免疫阳性细胞减少。nestin免疫阳性细胞增多。 7d后 ,其又减少。同时 NSE和 GFAP免疫阳性细胞增多。细胞分化后 ,NSE阳性细胞最多占细胞总数的 2 4 .76 %±2 .72 % ,同时 GFAP阳性细胞占细胞总数的 36 .5 8%± 3.2 6 %。结论　 EGF、b FGF、ATRA及适宜的培养液可使BMSCs定向 ,转化为 NSCs,进而分化为神经元和胶质细胞。     

Meningeal cells induce dopaminergic neurons from embryonic stem cells

Neural induction of midbrain dopaminergic (DA) neurons from embryonic stem (ES) cells can be achieved by culturing them on a bone marrow-derived stromal cell line, PA6, which possesses stromal cell-derived inducing activity (SDIA). The mechanism of SDIA is unknown, but clinical application of ES cell transplantation requires the use of defined factors for DA neuron induction. Here, we demonstrate that meningeal cells harvested from the developing dura can induce DA neuron differentiation from mouse and human ES cells, as assessed by midbrain DA marker expression and secretion of DA in response to potassium stimuli. Intriguingly, the inductive strength of meningeal cells depends on their developmental stage, with those harvested from embryonic day 18 embryos showing the highest activity. Among six soluble factors known to be involved in DA neuron differentiation, only Wnt-5a and transforming growth factor-β3 were expressed by both meningeal and PA6 cells, and the expression of Wnt-5a correlated with the DA neuron induction activity of these cells. Furthermore, the induction of DA neuron differentiation by PA6 cell-conditioned medium was reversed by addition of a Wnt-5a neutralizing antibody, whereas recombinant Wnt-5a promoted DA neuron induction when cells were cultured on Matrigel. These results indicate that meningeal cells can be used as feeders to induce DA neurons from ES cells, and that Wnt-5a plays an important role in DA neuron induction by SDIA.     

Lysophosphatidic acid activates satellite glia cells and Schwann cells

Pruritus is a common and disabling symptom in patients with hepatobiliary disorders, particularly in those with cholestatic features. Serum levels of lysophosphatidic acid (LPA) and its forming enzyme autotaxin were increased in patients suffering from hepatic pruritus, correlated with itch severity and response to treatment. Here we show that in a culture of dorsal root ganglia LPA 18:1 surprisingly activated a large fraction of satellite glia cells, and responses to LPA 18:1 correlated inversely with responses to neuronal expressed transient receptor potential channels. LPA 18:1 caused only a marginal activation of heterologously expressed TRPV1, and responses in dorsal root ganglion cultures from TRPV1-deficient mice were similar to controls. LPA 18:1 desensitized subsequent responsiveness to chloroquine and TGR5 agonist INT-777. The LPA 18:1-induced increase in cytoplasmatic calcium stems from the endoplasmatic reticulum. LPA receptor expression in dorsal root ganglia and Schwann cells, LPAR1 immunohistochemistry, and pharmacological results indicate a signaling pathway through LPA receptor 1. Peripheral rat Schwann cells, which are of glial lineage as the satellite glia cells, were also responsive to LPA 18:1. Summarizing, LPA 18:1 primarily activates rather glial cells than neurons, which may subsequently modulate neuronal responsiveness and sensory sensations such as itch and pain.     

成体骨髓细胞向神经细胞转化的特征

体外诱导骨髓基质干细胞分化为神经细胞已经成为神经科学研究的热点之一。目前在某些实验条件下,组织特异性的干细胞在组织和器官中能衍生为各种细胞谱系。已经有报道称骨髓基质细胞能衍生为骨骼细胞、胃贲门细胞、椭圆形肝细胞、神经胶质细胞和神经元样细胞。因此,通过资料研究分析出生后的骨髓细胞被诱导增殖进而分化为神经胶质细胞和神经元细胞,对其转化的特征作出探讨。