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

构成视网膜的主要细胞有感光细胞、视网膜神经节细胞和双极细胞。感光细胞分为感光和感光的杆状感光细胞和负责色觉的视锥感光细胞。在胚胎发育和体细胞再生过程中，视网膜前体细胞分化为双极细胞、视网膜神经节细胞、视锥感光细胞和视杆感光细胞已被广泛研究。然而，参与分化过程的分子还没有完全阐明。我们已经将参与眼睛发育的最重要的转录因子之一Pax6基因导入小鼠iPS细胞和小鼠ES细胞。在限制了Pax6转基因细胞的稀释培养后，我们建立了几个同时表达Nestin、Musashi1、Six3和chx10的视网膜神经前体细胞系，该转录因子在视网膜前体细胞分化中起重要作用。我们从iPS细胞建立的视网膜前体细胞对视网膜前体细胞标志物CD73有50%的阳性表达，并且在无刺激的条件下表达适量的视紫红质蛋白。在不同的趋化因子和生长因子的作用下，细胞分化为表达绿视蛋白、蓝视蛋白和红视蛋白的细胞。相反，以相同程序建立的ES细胞系主要分化为视网膜神经节细胞。总之，我们发现光感受器前体细胞分化为视锥感光细胞和杆状感光细胞受各自的趋化因子和生长因子的调控。

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.