Regenerative potential of retinal Muller glial cells

描述（由申请人提供）：本研究提案的目的是确定哺乳动物视网膜通过内源性机制进行修复的潜力。在视网膜损伤的反应中，几种脊椎动物模型系统的Muller神经胶质（MG）细胞已显示产生新的视网膜神经元。然而，在哺乳动物中，直接测试MG细胞体内再生能力的数据很少。我们的中心假设是，在视网膜损伤的反应，成熟的小鼠MG细胞具有重新进入细胞周期和转分化成视网膜神经元的能力。该提案的总体目标是通过进行遗传、Cre-loxP命运作图实验和时间推移成像来验证这一假设。目标1.确定小鼠Muller神经胶质细胞在特定环境背景下产生成熟视网膜神经元的能力。我们将测试的假设，视网膜米勒神经胶质（MG）细胞有能力再生视网膜神经元的化学诱导神经元变性和进行体内Cre-loxP命运映射实验。我们还将测试的假设，MG细胞的再生潜力显着受阻，由于神经胶质瘢痕形成的非许可的视网膜环境的结果。在这里，我们将进行相同的命运映射实验，但在波形蛋白-/-; Gfap-/-突变小鼠的遗传背景内，已知其表现出实质上更支持神经元移植的视网膜环境。目标二。阐明Muller胶质细胞对视网膜损伤和随后的转分化事件的反应的细胞机制。我们假设，在响应于损伤，MG细胞的离散子集重新进入细胞周期，并向视网膜的外界膜顶部移位，在那里它们进行有丝分裂，然后移位到适当的层分化神经元。为了验证这一假设，我们将进行实时成像的损伤诱导的视网膜外植体，其中MG细胞的荧光标记。神经元变性是一系列使人衰弱的人类认知和运动疾病的核心，包括阿尔茨海默氏病和帕金森氏病以及感觉疾病，如失明。通过表征视网膜内具有产生新神经元能力的细胞群，可以采用治疗方法来利用这些细胞的能力来治愈人类神经系统疾病。

DESCRIPTION (provided by applicant): The objective of this research proposal is to determine the potential of the mammalian retina for repair via endogenous mechanisms. In response to retinal damage, Muller glial (MG) cells of several vertebrate model systems have been shown to give rise to new retinal neurons. However, in mammals, there is a paucity of data directly testing the regenerative capacity of MG cells in vivo. Our central hypothesis is that, in response to retinal damage, mature mouse MG cells possess the ability to re-enter the cell cycle and trans-differentiate into retinal neurons. The overall goal of this proposal is to test this hypothesis by performing genetic, Cre-loxP fate mapping experiments and time lapse imaging. Aim 1. Determine the capacity of mouse Muller glial cells to give rise to mature retinal neurons within specific environmental contexts. We will test the hypothesis that retinal Muller glial (MG) cells have the ability to regenerate retinal neurons by chemically inducing neuronal degeneration and performing in vivo Cre-loxP fate-mapping experiments. We will also test the hypothesis that MG cell regenerative potential is significantly hindered as a consequence of a non-permissive retinal environment due to glial scarring. Here, we will perform the same fate-mapping experiment, but within the genetic background of Vimentin-/-; Gfap-/- mutant mice known to exhibit a retinal environment substantially more supportive of neuronal transplantation. Aim 2. Elucidate the cellular mechanisms of the Muller glial response to retinal damage and subsequent trans-differentiation events. We hypothesize that, in response to damage, a discrete subset of MG cells re-enter the cell cycle and translocate apically toward the outer limiting membrane of the retina where they undergo mitosis before translocating to the appropriate lamina as differentiating neurons. To test this hypothesis, we will perform live imaging of damage-induced retinal explants in which MG cells are fluorescently labeled. RELEVANCE Neuronal degeneration lies at the heart of a spectrum of debilitating human cognitive and motor diseases including Alzheimer's and Parkinson's disease as well as sensory diseases such as blindness. By characterizing cell populations within the retina, which have the ability to generate new neurons, therapeutic approaches could be employed to harness the ability of these cells to cure human neurological diseases.