Retinal Progenitors for Vision Rescue

描述(申请人提供)：视锥感光细胞是老年性黄斑变性中丢失的主要细胞类别。用于替代丢失的视锥细胞的疗法将需要丰富的这些独特细胞的来源。因此，显然有必要确定将更多的多能细胞类型定向到锥体谱系所需的分子机制。我们已经开发了一种独特的方法来解决这个问题。我们的结果表明，首先转化为原始外胚层的小鼠胚胎干细胞可以在培养中导向锥形细胞的命运。在体外，锥体的形成分别需要同时抑制BMP和激活成纤维细胞生长因子信号。在神经诱导过程中，这两条信号通路调节Smad1/5/8核转位(BMP)和Smad1/5/8核降解(Fgf)，从而引导外胚层细胞走向神经末梢。在这一应用中，我们概述了旨在通过调节典型和非典型BMP信号以及成纤维细胞生长因子信号来确定这些信号通路及其下游成分如何产生锥状光感受器命运的实验。我们的假设是，锥体的形成需要Smad1/5/8稳定性的调节。先前的研究已经清楚地表明，杆状祖细胞移植到宿主视网膜的发育阶段对细胞的成功分化和整合至关重要。我们的初步数据表明，锥体特异的蛋白质和光转导级联基因已经在我们的细胞中表达。表征它们的分子、形态和生理特性将有助于我们确定这些体外产生的视锥细胞的相对年龄。我们的研究非常符合国家眼睛和视觉研究目标(http://www.nei.nih.gov/strategicplanning/NP_strab.asp)，其中包括“确定干细胞在视觉系统的发育中如何分化，以及它们如何被用来理解视觉系统中特定细胞类型身份的分子逻辑。”该项目将确定促进视锥细胞生成的分子机制，并形成未来研究的基础，重点是这些细胞取代因视网膜损伤和退化而丢失的视锥细胞的能力。

DESCRIPTION (provided by applicant): Cone photoreceptors are the primarily cell class lost in Age-Related Macular Degeneration. Therapies designed to replace lost cones will require a rich source of these unique cells. Consequently, there is a clear need to identify the molecular mechanisms required to direct more plentiful pluripotent cells types to a cone lineage. We have developed a unique approach to addressing this problem. Our results demonstrate that mouse embryonic stem cells, first converted to primitive ectoderm, can be directed to a cone cell fate in culture. In vitro cone formation requires simultaneous repression of BMP and activation of FGF signaling, respectively. During neural induction, these two signaling pathways regulate SMAD1/5/8 nuclear translocation (BMP) and degradation (FGF), which directs ectodermal cells to a neural fate. In this application, we outline experiments designed to identify how these signaling pathways and their downstream components generate cone photoreceptor fate, by regulating both canonical and non-canonical BMP signaling as well as FGF signaling. Our hypothesis is that modulation of SMAD1/5/8 stability is required for cone formation. Previous studies have clearly demonstrated the developmental stage at which rod progenitors are transplanted to the host retina is critical for successful differentiation and integration of the cells. Our preliminary data demonstrates cone specific proteins and genes of the phototransduction cascade are already expressed in our cells. Characterizing their molecular, morphological and physiological properties will help us to determine the relative age of these in vitro-generated cones. Our research fits well into the National Plan for Eye and Vision Research objectives (http://www.nei.nih.gov/strategicplanning/ np_strab.asp), which include "determine(ing) how stem cells differentiate in the development of the visual system and how they can be used to understand the molecular logic of cell-type- specific identity in the visual system." This project will identify molecular mechanisms that contribute to cone cell generation and form the basis of future studies focusing on the ability of these cells to replace cones lost to retinal damage and degeneration.