Transcription Regulation In Vertebrate Eye Development

脊椎动物眼睛发育中的转录调控

• 批准号: 8158173
• 负责人: HEINZ ARNHEITER
• 金额: $ 85.51万
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8158173
• 关键词: Eye Development; Transcriptional Regulation

The vertebrate retina is abutted by retinal pigment epithelium (RPE) cells which provide various support functions regulating the homeostasis of the adjacent photoreceptor cells. RPE cells are developmentally derived from the optic neuroepithelium, as are retinal cells, and genetic manipulations indicate that the epithelial precursors to RPE cells can easily assume retinal cell fates and vice versa. In fact, cell specification is the result of the interplay between extracellular signaling molecules such as fibroblast growth factors or WNTs and transcription factors such as PAX6, MITF, and VAX1/2. Using genetic approaches in mice, we show, for instance, that a reduction in the level of functional PAX6 protein exacerbates the dorsal RPE-to-retina transdifferentiation that is normally found with Mitf mutations, and that overexpression of PAX6 protein alleviates this Mitf-mediated RPE-to-retina transdifferentiation. Further studies show that in the RPE, PAX6 normally reduces the expression of pro-retinogenic genes, while in the retina, it promotes their expression. While PAX6 and MITF thus regulate the boundary between retina and RPE, the ventral homeodomain proteins VAX1 and VAX2 together regulate the boundary between RPE and the epithelial connection to the brain, called the optic stalk. In fact, in Vax1/Vax2 double mutants, the dorsal optic stalk transdifferentiates into an RPE, and in Vax2/Mitf double mutants, the RPE-to-retina transdifferentiation is massively expanded compared with that seen in mice carrying only Mitf mutations. Hence, during vertebrate eye development, PAX6, MITF, and VAX1/2 are crucial to set up the correct boundaries between retina and RPE and between RPE and optic stalk. Given that the RPE provides critical support functions to the retina, it is not surprising that primary RPE pathologies are a major cause of human blindness. A possible approach to alleviate vision loss in RPE diseases is the use of healthy RPE cells for cell-based replacement therapies. Such cells can be generated, for instance, from induced pluripotent stem (iPS) cells. The process of in vitro RPE generation, however, is still relatively inefficient, and the phenotypic stability and authentic functionality of the cells far from guaranteed. Hence, using our insights into the role of cell-extrinsic and cell-intrinsic factors in RPE development, we shall explore the role of these factors for improvements in the efficiency and function of RPE cells generated in vitro.

脊椎动物视网膜由视网膜色素上皮（RPE）伸入，这些细胞提供了调节相邻感光细胞稳态的各种支持功能。 RPE细胞和视网膜细胞也从发育中衍生自视感神经上皮，遗传操作表明，RPE细胞的上皮前体可以轻松地假设视网膜细胞命运，反之亦然。实际上，细胞规范是细胞外信号分子（例如成纤维细胞生长因子）或WNT和转录因子（例如PAX6，MITF和VAX1/2）之间相互作用的结果。例如，使用小鼠中的遗传方法，我们表明，功能性PAX6蛋白水平的降低加剧了通常会通过MITF突变发现的背rPE-to-retina换分化，并且PAX6蛋白对PAX6蛋白的过表达减轻了这种MITF介导的RPE-RPE-介导的RPE-替代。进一步的研究表明，在RPE中，PAX6通常会降低促返回基因的表达，而在视网膜中，它促进了它们的表达。因此，PAX6和MITF调节视网膜和RPE之间的边界，而腹侧同源域蛋白VAX1和VAX2一起调节RPE和与大脑的上皮连接之间的边界，称为视茎。实际上，在VAX1/VAX2双重突变体中，背视性茎转变为RPE，在VAX2/MITF双突变体中，与仅携带MITF突变的小鼠相比，RPE到retina thrdindiation被大量扩展。因此，在脊椎动物的发育过程中，PAX6，MITF和VAX1/2对于在视网膜和RPE之间以及RPE和Optic Stalk之间建立正确的边界至关重要。 鉴于RPE为视网膜提供了关键的支持功能，因此原发性RPE病理是人类失明的主要原因也就不足为奇了。减轻RPE疾病视力丧失的可能方法是将健康的RPE细胞用于基于细胞的替代疗法。例如，可以从诱导的多能茎（IPS）细胞中产生此类细胞。然而，体外RPE产生的过程仍然相对效率低下，并且细胞的表型稳定性和真实功能远非保证。因此，利用我们对细胞超支和细胞中性因素在RPE发育中的作用的见解，我们将探讨这些因素在改善体外产生的RPE细胞效率和功能方面的作用。