Differentiation of retinal progenitors derived from ES cells and iPS cells.

构成视网膜的主要细胞是感光细胞、视网膜神经节细胞和双极细胞。光感受器细胞分为感知光和暗的杆状光感受器细胞和负责色觉的锥状光感受器。在胚胎发育和体细胞再生过程中，视网膜祖细胞向双极细胞、视网膜神经节细胞、视锥细胞和视杆细胞的分化被广泛研究。然而，参与分化过程的分子尚未完全澄清。我们引入了一个基因pax6，它是参与小鼠iPS细胞和小鼠胚胎干细胞眼睛发育的最重要的转录因子之一。在对pax6转染细胞进行有限稀释培养后，我们建立了几种同时表达nestin、musashi1、six3和chx10的视网膜神经祖细胞系，chx10是一种重要的视网膜祖细胞分化转录因子。我们从iPS细胞中建立的视网膜祖细胞表面CD73（一种视网膜祖细胞标记物）50%呈阳性，并且在非刺激条件下表达适量视紫红质蛋白。细胞在各种趋化因子和生长因子的作用下分化为表达绿视蛋白、蓝视蛋白和红视蛋白的细胞。相比之下，通过相同的程序从胚胎干细胞建立的细胞系主要分化为视网膜神经节细胞。总的来说，我们发现光感受器前体细胞分化为锥状光感受器和杆状光感受器细胞受到各自的趋化因子和生长因子的调节。

The main cells that make up the retina, are photoreceptor cells, retinal ganglion cells, and bipolar cells. The photoreceptor cells are classified into rod-photoreceptor cells for sensing light and dark, and the cone photoreceptors responsible for color vision.In the course of embryonal development and somatic regeneration occur, differentiation from retinal progenitor cells into bipolar cells, retinal ganglion cells, cone photoreceptors and rod-photoreceptor cells has been extensively studied. Nevertheless, molecules involved in the differentiation processes have not been fully clarified.We have introduced a gene pax6 which is one of the most important transcription factors involved in the eye development into mouse iPS cells and mouse ES cells. After limitingdilution culture of the pax6 transfected cells, we have established several retinal neural progenitor cell lines expressing simultaneously nestin, musashi1, six3, and chx10, a transcription factor which is importantly invod in differentiation of retinal progenitor cells. The retinal progenitor cells we have established from iPS cells are 50% positive for cell surface CD73, a retinal progenitor cell marker, and express a moderate amount of rhodopsin protein upon unstimulated condition. The cells differentiate into cells expressing green-opsin, blue-opsin, and red-opsin in response to various chemokines and growth factors.In contrast, cell lines established from ES cells with the same procedure differentiate into retinal ganglion cells predominantly. Collectively, we found that differentiation of photoreceptor precursor cells into cone photoreceptors and rod-photoreceptor cells areregulated by respective chemokines and growth factors.