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

胚胎视网膜是修复色素性视网膜炎等视网膜退化的可能细胞来源之一。从胚胎大鼠分离的视网膜祖细胞可在含表皮生长因子和碱性成纤维细胞生长因子的无血清培养基中培养和扩增。我们分析了两种不同的视网膜祖细胞在培养周期方面的特性。胚胎视网膜祖细胞能够扩增，保持未成熟细胞的特性，移植后具有从视网膜下空间向退化的成人视网膜迁移的能力。它们在体外和体内分化为神经元和胶质细胞，甚至分化为光感受器细胞。然而，在长期培养后，它们似乎失去了组织特异性。我们还发现，成年大鼠眼睛中的虹膜和睫状体组织在胚胎时期与神经视网膜相关，可以产生表达分化的神经元抗原的细胞。此外，Crx基因转移诱导虹膜源性细胞产生特异性杆状光感受器抗原，这在成体海马源性神经干细胞中未见。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围虹膜切除术获得

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