Identification of neural stem cells in neural retina, ciliary body and iris

胚胎视网膜是修复变性视网膜的可能细胞来源之一，如视网膜色素变性。从胚胎大鼠分离的视网膜前体细胞可以在含有表皮生长因子和碱性成纤维细胞生长因子的无血清培养液中培养和扩增。我们从培养周期的角度分析了两种不同的视网膜前体细胞的特性。胚胎视网膜的视网膜祖细胞可以扩增，保持未成熟的细胞特性，移植后能够从视网膜下腔向退化的成人视网膜迁移。它们在体外和体内分化为神经元和神经胶质细胞，甚至分化为光感受器细胞。然而，经过长期的培养，它们似乎失去了组织特异性。我们还表明，成年大鼠眼睛的虹膜和睫状体组织与神经视网膜有胚胎上的亲缘关系，可以产生表达分化的神经元抗原的细胞。此外，CRX基因转移在虹膜来源的细胞中诱导了杆状感光受体的特异性抗原，这在成年海马来源的神经干细胞中不存在。我们的研究结果表明成人虹膜组织具有显著的可塑性，具有潜在的临床应用价值，因为自体虹膜组织可以通过周边虹膜切除术获得。

Embryonic retina is one of the possible cell sources that will repair degenerated retina such as retimtis pigmentosa. Retinal progenitor cells isolated from embryonic rats could be cultured and expanded in serum free medium with both epidermal growth factor and basic fibroblast growth factor. We analyzed the properties of two different retinal progenitor cells in terms of culture periods. Retinal progenitor cells from embryonic retina could be expanded keeping immature cell properties and had the ability to migrate into degenerated adult retina from subretinal space after transplantation. They differentiated into neurons and glias, even into photoreceptor cells both in vitro and in vivo. However, they appeared to lose their tissue specificity after a long-term cultureWe also showed that iris and ciliary tissue in the adult rat eye, which are embryonically related to the neural retina, can generate cells expressing differentiated neuronal antigens. In addition, the Crx gene transfer induced the specific antigens for rod photoreceptors in the iris-derived cells, which was not seen in the adult hippocampus-derived neural stem cells. Our findings demonstrate a remarkable plasticity of adult iris tissue with potential clinical applications, as autologous iris tissue can be feasibly obtained with peripheral iridectomy