Center for Gene Therapy, Tulane University Health Sciences Center, New Orleans, Louisiana, USA.
Stem Cells Dev. 2011 Feb;20(2):289-300. doi: 10.1089/scd.2009.0444. Epub 2010 Sep 14.
Multipotent stem/progenitor cells from bone marrow stroma (mesenchymal stromal cells or MSCs) were previously shown to enhance proliferation and differentiation of neural stem cells (NSCs) in vivo, but the molecular basis of the effect was not defined. Here coculturing human MSCs (hMSCs) with rat NSCs (rNSCs) was found to stimulate astrocyte and oligodendrocyte differentiation of the rNSCs. To survey the signaling pathways involved, RNA from the cocultures was analyzed by species-specific microarrays. In the hMSCs, there was an upregulation of transcripts for several secreted factors linked to differentiation: bone morphogenetic protein 1 (BMP1), hepatocyte growth factor (HGF), and transforming growth factor isoforms (TGFβ1 and TGFβ3). In both the hMSCs and the rNSCs, there was an upregulation of transcripts for Notch signaling. The role of TGFβ1 was verified by the demonstration that hMSCs in coculture increased secretion of TGFβ1, the rNSCs expressed the receptor, and an inhibitor of TGFβ signaling blocked differentiation. The role of Notch signaling was verified by the demonstration that in the cocultures hMSCs expressed a Notch ligand at sites of cell contact with rNSCs, and the rNSCs expressed the receptor, Notch 1. Increased Notch signaling in both cell types was then demonstrated by assays of transcript expression and by a reporter construct for downstream targets of Notch signaling. The results demonstrated that glial differentiation of the rNSCs in the cocultures was driven by increased secretion of soluble factors such as TGFβ1 by the hMSCs and probably through increased cell contact signaling between the hMSCs and rNSCs through the Notch pathway.
骨髓基质中的多能干细胞/祖细胞（间充质基质细胞或 MSC）先前被证明可增强体内神经干细胞（NSC）的增殖和分化，但作用的分子基础尚不清楚。在此，将人 MSC（hMSC）与大鼠 NSC（rNSC）共培养发现可刺激 rNSC 的星形胶质细胞和少突胶质细胞分化。为了调查涉及的信号通路，通过物种特异性微阵列分析共培养物的 RNA。在 hMSC 中，与分化相关的几种分泌因子的转录物上调：骨形态发生蛋白 1（BMP1）、肝细胞生长因子（HGF）和转化生长因子同工型（TGFβ1 和 TGFβ3）。在 hMSC 和 rNSC 中，Notch 信号通路的转录物上调。通过证明共培养物中的 hMSC 增加 TGFβ1 的分泌、rNSC 表达受体以及 TGFβ 信号通路的抑制剂阻断分化，验证了 TGFβ1 的作用。通过证明在共培养物中 hMSC 在与 rNSC 接触的细胞部位表达 Notch 配体，而 rNSC 表达受体 Notch 1，验证了 Notch 信号通路的作用。然后通过测定转录物表达和 Notch 信号下游靶标的报告构建体，证明了两种细胞类型中 Notch 信号的增加。结果表明，rNSC 在共培养物中的神经胶质分化是由 hMSC 中可溶性因子（如 TGFβ1）的分泌增加以及 hMSC 和 rNSC 之间通过 Notch 通路的细胞接触信号增加驱动的。
