Hermann Andreas, Liebau Stefan, Gastl Regina, Fickert Stefan, Habisch Hans-Jörg, Fiedler Jörg, Schwarz Johannes, Brenner Rolf, Storch Alexander
Department of Neurology, Technical University of Dresden, Dresden, Germany.
J Neurosci Res. 2006 Jun;83(8):1502-14. doi: 10.1002/jnr.20840.
Human adult bone marrow-derived mesodermal stromal cells (hMSCs) are able to differentiate into multiple mesodermal tissues, including bone and cartilage. There is evidence that these cells are able to break germ layer commitment and differentiate into cells expressing neuroectodermal properties. There is still debate about whether this results from cell fusion, aberrant marker gene expression or real neuroectodermal differentiation. Here we extend our work on neuroectodermal conversion of adult hMSCs in vitro by evaluating various epigenetic conversion protocols using quantitative RT-PCR and immunocytochemistry. Undifferentiated hMSCs expressed high levels of fibronectin as well as several neuroectodermal genes commonly used to characterize neural cell types, such as nestin, beta-tubulin III, and GFAP, suggesting that hMSCs retain the ability to differentiate into neuroectodermal cell types. Protocols using a direct differentiation of hMSCs into a neural phenotype failed to induce significant changes in morphology and/or expression of markers of early and mature glial/neuronal cells types. In contrast, a multistep protocol with conversion of hMSCs into a neural stem cell-like population and subsequent terminal differentiation in mature glia and neurons generated relevant morphological changes as well as significant increase of expression levels of marker genes for early and late neural cell types, such as nestin, neurogenin2, MBP, and MAP2ab, accompanied by a loss of their mesenchymal properties. Our data provide an impetus for differentiating hMSCs in vitro into mature neuroectodermal cells. Neuroectodermally converted hMSCs may therefore ultimately help in treating acute and chronic neurodegenerative diseases. Analysis of marker gene expression for characterization of neural cells derived from MSCs has to take into account that several early and late neuroectodermal genes are already expressed in undifferentiated MSCs.
人类成人骨髓来源的中胚层基质细胞（hMSCs）能够分化为多种中胚层组织，包括骨骼和软骨。有证据表明，这些细胞能够打破胚层限制，分化为表达神经外胚层特性的细胞。关于这是由细胞融合、异常标记基因表达还是真正的神经外胚层分化导致的，仍存在争议。在这里，我们通过使用定量RT-PCR和免疫细胞化学评估各种表观遗传转化方案，扩展了我们在体外对成人hMSCs进行神经外胚层转化的研究。未分化的hMSCs表达高水平的纤连蛋白以及几种常用于表征神经细胞类型的神经外胚层基因，如巢蛋白、β-微管蛋白III和胶质纤维酸性蛋白（GFAP），这表明hMSCs保留了分化为神经外胚层细胞类型的能力。使用将hMSCs直接分化为神经表型的方案未能诱导早期和成熟神经胶质/神经元细胞类型标志物的形态和/或表达发生显著变化。相比之下，一种多步骤方案，即先将hMSCs转化为神经干细胞样群体，随后在成熟神经胶质细胞和神经元中进行终末分化，产生了相关的形态变化以及早期和晚期神经细胞类型标志物基因表达水平的显著增加，如巢蛋白、神经生成素2、髓鞘碱性蛋白（MBP）和微管相关蛋白2ab（MAP2ab），同时伴随着它们间充质特性的丧失。我们的数据为在体外将hMSCs分化为成熟神经外胚层细胞提供了动力。因此神经外胚层转化的hMSCs最终可能有助于治疗急性和慢性神经退行性疾病。对源自MSCs的神经细胞进行表征时，分析标志物基因表达必须考虑到几种早期和晚期神经外胚层基因在未分化的MSCs中已经表达。
