骨髓基质细胞对神经-干细胞分化为神经元的影响

采用细胞共培养方式和免疫化学染色方法,研究骨髓基质细胞对神经干细胞分化为神经元、星形胶质细胞和寡突胶质细胞的影响.实验发现,体外培养的中脑神经干细胞在与成年大鼠骨髓基质细胞共培养7 d后,在神经干细胞后代中神经元比例可达38.6%±10.8%,明显高于自然分化组20%,提示骨髓基质细胞提供的微环境可明显提高神经干细胞后代中神经元的比例.     

骨髓基质细胞对人胚胎神经干细胞分化极性的诱导

目的 :建立骨髓基质细胞及人胚胎神经干细胞共培养系统并观察其对神经干细胞的诱导分化作用。方法 :来源于人胚胎脑组织不同脑区的神经干细胞分别与骨髓基质细胞建立起各自的共培养系统并在其中纯化 ,以CM、CO CM、BMSC对神经干细胞进行诱导分化 ,并通过免疫荧光及免疫细胞化学技术检测神经元的诱导率。结果 :骨髓基质细胞及其共培养系统培养液能够明显地提高神经元的分化率。结论 :共培养系统诱发了神经干细胞与骨髓基质细胞的自分泌与旁分泌的作用并改变了神经干细胞的分化极性     

人胚神经干细胞定向诱导分化为多巴胺能神经元的实验研究

目的　建立神经干细胞与骨髓基质细胞的共培养系统,根据该系统的条件性培养液诱导多巴胺能神经元的分化。方法　来源于胎脑海马、纹状体、额叶、中脑的神经干细胞与骨髓基质细胞建立起各自的共培养系统,并根据数种条件性培养液诱导神经干细胞的分化,以免疫细胞化学检测神经元的总体分化率及多巴胺能神经元的诱导率。结果　骨髓基质细胞及CO-BMSC能显著提高不同来源的神经干细胞的神经元分化率,同时只有中脑神经干细胞能被有效地进行多巴胺能神经元的诱导。结论 共培养系统诱发了神经干细胞与骨髓基质细胞的自/旁分泌作用,该作用可根据神经干细胞的区域特异性有效的定向诱导中脑神经干细胞的分化。     

猫骨髓源性神经干细胞诱导分化的实验研究

目的探讨猫骨髓分离培养、诱导分化神经干细胞的可行性。方法无菌条件下行骨穿,梯度密度离心获取猫骨髓基质细胞,以“神经干细胞培养基”培养,用分化诱导因子进行体外培养和诱导分化。结果猫骨髓基质细胞在相应培养条件下能在体外培养中增殖、分化,克隆形成细胞球(或称“神经球”),这些细胞球能表达神经干细胞特异性抗原nestin,而且能进一步诱导分化出胶质样细胞和神经元样细胞,免疫细胞化学检测可见有胶质源性纤维酸性蛋白抗体(GFAP)和神经元特异性烯醇化酶(NSE)抗原表达。结论猫骨髓基质细胞在一定条件诱导下可分化成神经胶质样和神经元样细胞。     

骨髓间充质干细胞向多巴胺能神经元的诱导分化

背景：近年来研究发现,神经营养因子在骨髓间充质干细胞的分化中发挥重要作用。目前脑组织中具有再生能力的神经干细胞在体外是否具有直接诱导骨髓间充质干细胞分化为多巴胺能神经元的作用还未见报道。 目的：观察大鼠间充质干细胞在胶质细胞源性神经营养因子与神经干细胞共培养两种诱导条件下体外分化成多巴胺能神经元的能力。 方法：分离培养SD大鼠骨髓间充质干细胞,取第3代细胞分2组培养,一组细胞应用胶质细胞源性神经营养因子单独诱导,另一组细胞与已培养成球的神经干细胞共培养进行诱导,共培养之前行Brdu标记。诱导3 d后以免疫组织化学法检测各组贴壁细胞神经元特异性标志物神经原纤维和多巴胺能神经元特异性标志物酪氨酸羟化酶的表达,观察间充质干细胞的分化情况。 结果与结论：胶质细胞源性神经营养因子单独诱导组间充质干细胞在诱导24 h后胞体回缩呈锥形,突起延长且数量增多,有神经元样形态,且细胞间相互连接成网络状,3 d后部分细胞表达神经原纤维,其中少部分同时表达酪氨酸羟化酶。与神经干细胞共培养组神经干细胞球很快解离,迅速贴壁,共培养的贴壁细胞大量增殖且多呈神经元样,胞体细长多突起,相互间连接成网,多数贴壁细胞分别单独表达神经原纤维和酪氨酸羟化酶,少数细胞可见Brdu/神经原纤维,Brdu/胶质纤维酸性蛋白,Brdu/酪氨酸羟化酶双标阳性。提示间充质干细胞在胶质细胞源性神经营养因子、神经干细胞存在的情况下可定向转化为神经元,并有向多巴胺能神经元分化的可能。在该实验条件下胶质细胞源性神经营养因子效果好于神经干细胞。     

成鼠骨髓基质细胞向神经干细胞诱导分化的实验研究

目的研究成鼠骨髓基质细胞体外培养的生长行为和分化情况。方法利用EGF、FGF-b等增殖及分化诱导因子和神经干细胞培养液进行培养,分化诱导,用细胞免疫组化染色进行细胞鉴定。结果成鼠骨髓基质细胞在体外培养中能形成细胞克隆团,具有增殖能力,并可分化出胶质细胞样细胞和神经元样细胞。结论骨髓基质细胞具有较强的自我更新及多向分化能力,在适宜的诱导分化条件下,可诱导为神经干细胞,分化出神经元和胶质细胞。     

星形胶质细胞源性因子对神经干细胞分化的实验研究

目的探讨星形胶质细胞源性因子对神经干细胞分化的影响。方法分离和培养新生大鼠脑组织的神经干细胞;采用差速贴壁法和振荡法分离纯化星形胶质细胞,用免疫细胞化学染色法,胶质纤维酸性蛋白(GFAP)标记星形胶质细胞,进行细胞的纯度鉴定;将星形胶质细胞和神经干细胞在互不接触的情况下进行共培养,免疫荧光法观察神经干细胞分化后神经元特异性烯醇化酶(NSE)、GFAP和酪氨酸羟化酶(TH)的表达。结果纯化的星形胶质细胞GFAP抗体标记阳性,细胞纯度达98%;星形胶质细胞与神经干细胞共培养时,神经干细胞贴壁分化加快,NSE阳性细胞及TH阳性细胞明显多于对照组(P<0·05)。结论星形胶质细胞源性因子可快速诱导神经干细胞向神经元细胞、包括多巴胺神经元细胞分化,提示星形胶质细胞支持神经元发生。     

人骨髓间充质干细胞诱导向多巴胺能神经元的分化

背景：体内外研究发现人骨髓间充质干细胞分化为神经元的比率都明显低于胶质细胞,并且这为数不多的神经元会逐渐死亡,而最终存活的细胞中神经元的数量更少。 目的：观察人骨髓间充质干细胞体外诱导分化为多巴胺能神经元的潜能。 方法：分离纯化和扩增人骨髓间充质干细胞,在体外先用碱性成纤维细胞生长因子和表皮细胞生长因子进行预诱导后,以胶质细胞源性神经营养因子和血管紧张素Ⅱ联合诱导人骨髓间充质干细胞向神经元和多巴胺能神经元分化。观察分化过程中细胞的形态变化,利用免疫组织化学检测神经元和多巴胺能神经元特异性标志物的表达情况。 结果与结论：人骨髓间充质干细胞经诱导后的细胞呈现双极、多极和锥形的典型神经元细胞的形态,明显表达抗人神经巢蛋白[(55.7±4.3)%]和神经元特异性烯醇化酶[(78.2±6.7)%],而且大部分人骨髓间充质干细胞表达酪氨酸羟化酶[(48.5±5.6)%],不表达神经胶质细胞标记物胶质纤维酸性蛋白。提示在适宜的条件下,人骨髓间充质干细胞可分化成神经元和多巴胺能神经元样细胞。     

猫骨髓基质细胞诱导为神经干细胞的实验研究

目的观察猫骨髓基质细胞体外培养及诱导分化情况。方法从猫的骨髓中分离得到骨髓基质细胞(Bone Marrow Stromal cells．BMSC），在体外给予神经干细胞培养基培养，增殖后用分化诱导因子(维甲酸，Retinoic acid，RA)进行诱导分化．倒置相差显微镜下观察活细胞及免疫细胞化学染色情况。结果猫骨髓基质细胞在体外培养中胞体增大，镜下可见丰富的胞浆颗粒，继之出芽，贴壁生长，可形成克隆团，同时可传代培养。这些具有克隆能力的骨髓基质细胞能表达神经干细胞特异性抗原nestin，而且能分化出胶质细胞样细胞和神经元样细胞。结论猫骨髓基质细胞具有干细胞特征，在合适的条件下可扩增、形成克隆并诱导分化出神经胶质细胞和神经元特征细胞，它们可考虑作为神经系统功能缺失细胞移植治疗的种子细胞来源。     

小胶质细胞对体外培养神经干细胞向胆碱能神经元分化的影响

背景：神经干细胞的定向分化与小胶质细胞的浓度有关，浓度倍数过小可能达不到应有效应，太大则会产生细胞毒性。 目的：观察不同比例的小胶质细胞对体外培养的神经干细胞向胆碱能神经元方向分化的影响。 方法：取新生24，48 h内Wistar大鼠用于神经干细胞与小胶质细胞的原代培养，免疫组化进行鉴定。神经干细胞与小胶质细胞共同接种于6孔板，接种密度分别为10∶1，4∶1，1∶1，1∶4，1∶10，每种密度设6孔，以单纯神经干细胞作为对照，共培养3，7，14 d，观察细胞的生长情况。 结果与结论：原代培养的神经干细胞聚集成球状，悬浮生长，Nestin染色阳性，胞核不着色。小胶质细胞贴壁生长，折光性强，大部分细胞有短的突起呈分支状，小胶质细胞特异性标记抗体CD11b/c染色结果显示细胞纯度在80%以上。与单纯神经干细胞对照组相比，神经干细胞与小胶质细胞以10∶1，4∶1，1∶1，1∶4，1∶10接种密度共培养组ChAT阳性细胞数均明显升高。共培养组神经干细胞与小胶质细胞比例为4∶1时升高幅度显著高于其他接种密度 (P < 0.05)，且在培养第7天时生长达到高峰。结果提示小胶质细胞可以促进神经干细胞向胆碱能神经元方向分化，神经干细胞与小胶质细胞4∶1比例共培养第7天时效果最佳。     

miR-124 and miR-128 differential expression in bone marrow stromal cells and spinal cord-derived neural stem cells

BACKGROUND: MicroRNA (miRNA) expression in stem cells provides important clues for the molecular mechanisms of stem cell proliferation and differentiation. Bone marrow stromal cells and spinal cord-derived neural stem cells exhibit potential for neural regeneration. However, miRNA expression in these cells has been rarely reported. OBJECTIVE: To explore differential expression of two nervous system-specific miRNAs, miR-124 and miR-128, in bone marrow stromal cells and spinal cord-derived neural stem cells.DESIGN, TIME AND SETTING: An In vitro, cell biology experiment was performed at the Department of Biotechnology, Shanxi Medical University from June 2008 to June 2009.MATERIALS: TaqMan miRNA assays were purchased from Applied Biosystems. METHODS: Rat bone marrow stromal cells were isolated and cultured using the whole-bone marrow method, and rat spinal cord-derived neural stem cells were obtained through neurosphere formation. TaqMan miRNA assays were used to measure miR-124 and miR-128 expression in bone marrow stromal cells and spinal cord-derived neural stem cells.MAIN OUTCOME MEASURES: Morphology of bone marrow stromal cells and spinal cord-derived neural stem cells were observed by inverted microscopy. Expression of the neural stem cell-specific marker, nestin, the bone marrow stromal cell surface marker, CD71, and expression of miR-124 and miR-128, were detected by real-time polymerase chain reaction. RESULTS: Cultured bone marrow stromal cells displayed a short fusiform shape. Flow cytometry revealed a large number of CD71-positive cells (> 95%). Cultured spinal cord-derived neural stem cells formed nestin-positive neurospheres, and quantitative detection of miRNA demonstrated that less miR-124 and miR-128 was expressed in bone marrow stromal cells compared to spinal cord-derived neural stem cells (P < 0.05). CONCLUSION: Bone marrow stromal cells and spinal cord-derived neural stem cells exhibited differential expression of miR-124 and miR-128, which suggested different characteristics in miRNA expression.     

血清和雪旺氏细胞诱导大鼠胚胎神经干细胞分化的比较

目的 比较血清和雪旺氏细胞诱导大鼠胚胎神经干细胞分化的差异。方法 分别采用血清和与雪旺氏细胞共培养的方法诱导大鼠胚胎神经干细胞分化，应用相差显微镜和免疫荧光染色的方法对其进行观察和比较。结果 两种方法都能够诱导绝大多数神经干细胞分化成神经元，少量分化成星形胶质细胞和少突胶质细胞。虽然后一种方法诱导干细胞分化的进程比前一种方法要慢，但细胞形态学上更接近发育成熟的神经元。结论 雪旺氏细胞的分泌物不仅能够诱导共培养的神经干细胞分化，而且使其分化更加成熟。     

The effect of bone marrow stromal cells on neuronal differentiation of mesencephalic neural stem cells in Sprague-Dawley rats

There are numerous parallels between the heamatolymphopoietic and nervous systems in terms of the mechanisms regulating their development. We proposed that neural stem cells (NSCs) may respond to the microenvironmental signals provided by bone marrow stromal cells (BMSCs) which regulate the differentiation and maturation of hematolymphopoietic stem cells. First, we isolated and proliferated BMSCs from the femur and tibia, and NSCs from the midbrain of Sprague-Dawley (SD) rats, and then investigated the effects of BMSCs on the differentiation of NSCs into neurons, astrocytes and oligodendrocytes by directly plating neurospheres on BMSC monolayers in serum-free conditions. The results confirmed that BMSCs induced NSCs to differentiate selectively into neurons. The percentage of neurons significantly increased in 7 days in vitro co-cultures of NSCs and BMSCs as compared to NSCs cultures alone. When the duration of the cultures was extended to 12 days in vitro, BMSCs enhanced the survival of neurons derived from these NSCs; our investigation then focused on the underlying mechanism for this effect of BMSCs. NSCs were cultured with BMSC conditioned-medium and co-cultured with membrane fragments of live BMSCs or paraformaldehyde fixed BMSCs, the inducing activity of BMSCs was solely detectable in BMSC conditioned-medium, indicating that soluble factors secreted by BMSCs were responsible for its effect on the neuronal differentiation of NSCs. Therefore, BMSCs may provide a powerful tool for therapeutic neurological applications.     

Phenotypic characterization of neural stem cells from human fetal spinal cord: synergistic effect of LIF and BMP4 to generate astrocytes

If cell based therapy for spinal cord injury is to become a reality, greater insights into the biology of human derived spinal cord stem cells are a prerequisite. Significant species differences and regional specification of stem cells necessitates determining the effects of growth factors on human spinal cord stem cells. Fetal spinal cords were dissociated and expanded as neurospheres in medium with bone morphogenetic protein 4 (BMP4), leukemia inhibitory factor (LIF) or BMP4 and LIF. First-generation neurospheres comprised a heterogeneous population of neural cell types and after plating emergent cells included neurons, oligodendrocytes and GFAP(+) cells which coexpressed stem cells markers and those of the neuronal lineage and were thus identified as GFAP(+) neural precursor cells (NPC). When plated, neurospheres maintained in BMP4 demonstrated a reduced proportion of emergent oligodendrocytes from 13 to 4%, whereas LIF had no statistically significant effect on cell type distribution. Combining BMP4 and LIF reduced the proportion of oligodendrocytes to 3% and that of neurons from 37 to 16% while increasing the proportion of GFAP(+) NPC from 45 to 79%. After 10 passages in control media aggregates gave rise to multiple neural phenotypes and only continued passage of neurospheres in the presence of BMP4 and LIF resulted in unipotent aggregates giving rise to only astrocytes. These results provide a means of obtaining pure populations of human spinal-cord derived astrocytes, which could be utilized for further studies of cell replacement strategies or in vitro evaluation of therapeutics.     

Generation of neural stem cell-like cells from bone marrow-derived human mesenchymal stem cells

Under appropriate culture conditions, bone marrow (BM)-derived mesenchymal stem cells are capable of differentiating into diverse cell types unrelated to their phenotypical embryonic origin, including neural cells. Here, we report the successful generation of neural stem cell (NSC)-like cells from BM-derived human mesenchymal stem cells (hMSCs). Initially, hMSCs were cultivated in a conditioned medium of human neural stem cells. In this culture system, hMSCs were induced to become NSC-like cells, which proliferate in neurosphere-like structures and express early NSC markers. Like central nervous system-derived NSCs, these BM-derived NSC-like cells were able to differentiate into cells expressing neural markers for neurons, astrocytes, and oligodendrocytes. Whole-cell patch clamp recording revealed that neuron-like cells, differentiated from NSC-like cells, exhibited electrophysiological properties of neurons, including action potentials. Transplantation of NSC-like cells into mouse brain confirmed that these NSC-like cells retained their capability to differentiate into neuronal and glial cells in vivo. Our data show that multipotent NSC-like cells can be efficiently produced from BM-derived hMSCs in culture and that these cells may serve as a useful alternative to human neural stem cells for potential clinical applications such as autologous neuroreplacement therapies.     

干细胞在脑性瘫痪治疗中的应用

背景：干细胞在适当条件下可以分化为神经元细胞、星形胶质细胞与少突胶质细胞，可能从根本上改善脑性瘫痪患儿神经元缺失及神经胶质细胞变性，进而改善患儿脑功能障碍，从理论上达到根治目的。 目的：回顾性分析不同来源干细胞经不同途径治疗脑性瘫痪患儿的疗效。 方法：由第一作者检索1992/2011 PubMed数据及万方数据库有关脑性瘫痪的治疗及不同来源干细胞在治疗脑性瘫痪等方面的文献。 结果与结论：神经干细胞在动物神经功能损伤中的修复作用已有很多国内外报道，但目前其在人体的临床应用仍处于临床试验阶段。虽然胚胎、骨髓血、胎儿脐带血、脐带来源的干细胞已在部分医院应用到脑性瘫痪患儿中，并取得了初步的疗效，其具体评定标准及长期疗效仍有待进一步随访、观察。     

Transplanted hematopoietic stem cells from bone marrow differentiate into neural lineage cells and promote functional recovery after spinal cord injury in mice

Recovery in central nervous system disorders is hindered by the limited ability of the vertebrate central nervous system to regenerate lost cells, replace damaged myelin, and re-establish functional neural connections. Cell transplantation to repair central nervous system disorders is an active area of research, with the goal of reducing functional deficits. Recent animal studies showed that cells of the hematopoietic stem cell (HSC) fraction of bone marrow transdifferentiated into various nonhematopoietic cell lineages. We employed a mouse model of spinal cord injury and directly transplanted HSCs into the spinal cord 1 week after injury. We evaluated functional recovery using the hindlimb motor function score weekly for 5 weeks after transplantation. The data demonstrated a significant improvement in the functional outcome of mice transplanted with hematopoietic stem cells compared with control mice in which only medium was injected. Fluorescent in situ hybridization for the Y chromosome and double immunohistochemistry showed that transplanted cells survived 5 weeks after transplantation and expressed specific markers for astrocytes, oligodendrocytes, and neural precursors, but not for neurons. These results suggest that transplantation of HSCs from bone marrow is an effective strategy for the treatment of spinal cord injury.     

Human neural stem cells genetically modified for brain repair in neurological disorders

Existence of multipotent neural stem cells (NSC) has been known in developing or adult mammalian CNS, including humans. NSC have the capacity to grow indefinitely and have multipotent potential to differentiate into three major cell types of CNS, neurons, astrocytes and oligodendrocytes. Stable clonal lines of human NSC have recently been generated from the human fetal telencephalon using a retroviral vector encoding v‐myc. One of the NSC lines, HB1.F3, carries normal human karyotype of 46XX and has the ability to self‐renew, differentiate into cells of neuronal and glial lineages, and integrate into the damaged CNS loci upon transplantation into the brain of animal models of Parkinson disease, HD, stroke and mucopolysaccharidosis. F3 human NSC were genetically engineered to produce L‐dihydroxyphenylalanine (L‐DOPA) by double transfection with cDNA for tyrosine hydroxylase and guanosine triphosphate cylohydrolase‐1, and transplantation of these cells in the brain of Parkinson disease model rats led to L‐DOPA production and functional recovery. Proactively transplanted F3 human NSC in rat striatum, supported the survival of host striatal neurons against neuronal injury caused by 3‐nitropro‐pionic acid in rat model of HD. Intravenously introduced through the tail vein, F3 human NSC were found to migrate into ischemic lesion sites, differentiate into neurons and glial cells, and improve functional deficits in rat stroke models. These results indicate that human NSC should be an ideal vehicle for cell replacement and gene transfer therapy for patients with neurological diseases. In addition to immortalized human NSC, immortalized human bone marrow mesenchymal stem cell lines have been generated from human embryonic bone marrow tissues with retroviral vectors encording v‐myc or teromerase gene. These immortalized cell lines of human bone marrow mesenchymal stem cells differentiated into neurons/glial cells, bone, cartilage and adipose tissue when they were grown in selective inducing media. There is further need for investigation into the neurogenic potential of the human bone marrow stem cell lines and their utility in animal models of neurological diseases.     

Human stem cells isolated from adult skeletal muscle differentiate into neural phenotypes

Multipotent neural stem cells have been isolated from the adult [Kirschenbaum B, Nedergaard M, Preuss A, Barami K, Fraser RA, Goldman SA. In vitro neuronal production and differentiation by precursor cells derived from the adult human forebrain. Cereb Cortex 1994;4(6):576-89; Laywell ED, Kukekov VG, Steindler DA. Multipotent neurospheres can be derived from forebrain subependymal zone and spinal cord of adult mice after protracted postmortem intervals. Exp Neurol 1999;156:430-3; Pluchino S, Quattrini A, Brambilla E, Gritti A, Salani G, Dina G, et al. Injection of adult neurospheres induces recovery in a chronic model of multiple sclerosis. Nature 2003;422:688-94] and embryonic [Vescovi AL, Parati EA, Gritti A, Poulin P, Ferrario M, Wanke E, et al. Isolation and cloning of multipotential stem cells from the embryonic human CNS and establishment of transplantable human neural stem cell lines by epigenetic stimulation. Exp Neurol 1999;156:71-83] central nervous system (CNS). In addition, neural cells can be obtained from sources other than the CNS by differentiating stem cells from a non-neural source down a neural lineage. This has previously been performed with pluripotent embryonic stem cells and adult stem cells derived from rat bone marrow [Woodbury D, Schwarz EJ, Prockop DJ, Black IB. Adult rat and human bone marrow stromal cells differentiate into neurons. J Neurosci Res 2000;61:364-70; Woodbury D, Reynolds K, Black IB. Adult bone marrow stromal stem cells express germline, ectodermal, endodermal, and mesodermal genes prior to neurogenesis. J Neurosci 2002;69(6):908-17] and skeletal muscle [Romero-Ramos M, Vourc'h P, Young HE, Lucas PA, Wu Y, Chivatakarn O, et al. Neuronal differentiation of stem cells isolated from adult muscle. J Neurosci Res 2002;69:894-907]. Previously, we have isolated adult stem cells from human skeletal muscle with the potential to differentiate into mesoderm, ectoderm, and endoderm. The following in vitro experiments were designed to determine whether human adult stem cells behaved similarly to rat adult stem cells when both were isolated from skeletal muscle by the same procedure [Romero-Ramos M, Vourc'h P, Young HE, Lucas PA, Wu Y, Chivatakarn O, et al. Neuronal differentiation of stem cells isolated from adult muscle. J Neurosci Res 2002;69:894-907] and subjected to the same protocols to induce neurogenesis. The neural phenotypes that were created through the neurococktail or neurosphere protocol were analyzed for neural characteristics through morphology and immunohistochemistry antibody labeling for proteins to neurons (RT-97, beta-tubulin III, NF-160, NF-200, and synapsin), oligodendrocytes (CNPase and RIP), and astrocytes (GFAP). A calcium uptake assay also showed response to the neuronal excitotoxic agent glutamic acid. In conclusion, the neural differentiated stem cells derived from adult skeletal muscle may be a less invasive alternative for the treatment of CNS disorders over CNS derived neural stem cells.     

Absence of hematopoiesis from transplanted olfactory bulb neural stem cells

Neural stem cells giving rise to neurons and glia cells have been isolated from the embryonic and adult central nervous system. The extent to which they are able to differentiate into cells of non-neural lineages, such as the hematopoietic lineage, is nonetheless unclear. We previously reported the isolation of stem cells from the mouse olfactory bulb neuroepithelium. In the present study, we analysed whether olfactory bulb stem cells (OBSC) can generate cells with hematopoietic features. Cells were prepared from the olfactory bulbs of transgenic mice expressing enhanced green fluorescent protein (EGFP). In culture, transgenic cells proliferated with the same kinetics as wild-type cells. Following mitogen removal, both cell types gave rise to similar numbers of neurons, astrocytes and oligodendrocytes, indicating that EGFP overexpression does not alter OBSC proliferation and differentiation patterns. When these cells were injected into the tail vein of irradiated mice, no hematopoietic cells derived from the OBSC could be recovered in their peripheral blood, spleen or bone marrow. By contrast, when OBSC were transplanted into the adult brain, EGFP-positive cells were found in the striatum and corpus callosum; differentiated cells expressed antigenic markers of neurons and astrocytes. These results suggest that embryonic olfactory bulb stem cells are not endowed with the potential to produce hematopoiesis.