Ahmad I, Dooley C M, Thoreson W B, Rogers J A, Afiat S
Department of Cell Biology and Anatomy, University of Nebraska Medical Center, 600 South 42nd Street, Omaha, NE 68198-6395, USA.
Brain Res. 1999 Jun 12;831(1-2):1-10. doi: 10.1016/s0006-8993(99)01376-1.
In vivo lineage studies have shown that retinal cells arise from multipotential progenitors whose fates are regulated by cell-cell interactions. To understand the mechanism underlying their maintenance and differentiation, we have analyzed the differentiation potential of progenitors derived from embryonic rat retina in vitro. These progenitors proliferate and remain undifferentiated in vitro in the presence of epidermal growth factor (EGF) and display properties similar to stem cells. In addition to expressing nestin, the neuroectodermal stem cell marker, retinal progenitors are multipotential. Upon withdrawal of EGF and addition of serum, the progenitors downregulate the expression of nestin and express cell-type specific markers corresponding to neurons and glia. In addition to expressing cell-type specific markers, retinal progenitors and their progeny could be distinguished on the basis of their distinct voltage gated current profile. A proportion of progenitors is lineage restricted and the fate of these cells can be influenced by the microenvironment, suggesting that stage-specific interactions mediated by the local environment influence the progression of progenitors towards acquisition of differentiated phenotypes.
体内谱系研究表明，视网膜细胞起源于多能祖细胞，其命运受细胞间相互作用调控。为了解其维持和分化的潜在机制，我们在体外分析了源自胚胎大鼠视网膜的祖细胞的分化潜能。这些祖细胞在表皮生长因子（EGF）存在的情况下在体外增殖并保持未分化状态，表现出与干细胞相似的特性。除了表达神经外胚层干细胞标志物巢蛋白外，视网膜祖细胞具有多能性。在撤除EGF并添加血清后，祖细胞下调巢蛋白的表达，并表达与神经元和神经胶质细胞相对应的细胞类型特异性标志物。除了表达细胞类型特异性标志物外，视网膜祖细胞及其后代还可根据其独特的电压门控电流特征加以区分。一部分祖细胞具有谱系限制，这些细胞的命运会受到微环境的影响，这表明由局部环境介导的阶段特异性相互作用会影响祖细胞向获得分化表型的进展。
