Functional differentiation of neural stem cells into smooth muscle cells.

我们已经建立了中枢神经系统中的神经干细胞(NSCs)向平滑肌细胞(SMC)和内皮细胞的分化。为了研究NSC来源的SMC是否具有收缩平滑肌(SM)的特征，我们制备了NSC来源的SMC的重组SM纤维，并测量了其收缩张力。对Kc1、ACh和ET-1的反应使纤维收缩。ACh引起的收缩可被硝苯地平部分抑制，并被MLCK抑制剂ML-9和Rho-Kinase抑制剂Y-27632完全阻断，提示SMC存在SM收缩机制。为检测神经干细胞来源的内皮细胞能否在体外形成血管管样结构，将分化后的细胞接种于含10%胎牛血清和碱性成纤维细胞生长因子的胶原凝胶中，培养5d，形成由PECAM-1或VE-钙粘素免疫反应细胞组成的血管样管结构。此外，偶见大量α-平滑肌肌动蛋白免疫反应细胞包被的血管管样结构的形成。这些结果提示，神经干细胞在体外可分化为内皮细胞和平滑肌细胞两种类型的血管细胞，它们具有形成血管管的能力。这些结果提出了一种可能性，即头部的血管至少部分来自神经干细胞。

We have established the differentiation of neural stem cells (NSCs) in the CNS into smooth muscle cells (SMCs) and endothelial cells. To examine whether NSC-derived SMCs possess a characteristic of contractile smooth muscle (SM), we have prepared a reconstituted SM fiber of NSC-derived SMCs and measured its contractile tension. The fiber contracted in response to KC1, ACh, and endothelin-1. ACh-induced contraction was partially inhibited by nifedipine and completely abolished by the MLCK inhibitor ML-9 and the Rho-kinase inhibitor Y-27632, suggesting that SM contractile mechanisms are present in the SMCs. To examine whether NSC-derived endothelial cells can form a vascular tube-like structure in vitro, the differentiated cells were inoculated in collagen gels with 10% FBS and bFGF and incubated for 5 days, vessel-like tube structures consisting of PECAM-1-or VE-cadherin-immunoreactive cells were formed in the gels. Moreover, the formation of vascular tube-like structures with a massive investment of α-smooth muscle actin-immunoreactive cells was occasionally observed. These results suggested that NSCs give rise to two types of vascular cells, endothelial cells and SMCs in vitro, which have the ability to form vascular tubes. These results arise one possibility that blood vessels in head are at least in part derived from NSCs.