Synapses in Regenerated Retina

 描述（由申请人提供）：人的视网膜变性疾病和视网膜创伤导致视网膜神经元的进行性损失并导致视觉功能降低，部分原因是哺乳动物视网膜不通过产生替代神经元对神经元的损失做出固有响应。NEI最近宣布了它的大胆目标，“再生眼睛和视觉系统中的神经元和神经连接。“这一目标可以通过开发激活内源性视网膜细胞以显示再生特性的策略来实现，和/或通过从外源性来源移植替代视网膜神经元或其祖细胞来实现。实现这一大胆目标的挑战包括鉴定哺乳动物内源性细胞激活的机制，建立视网膜祖细胞，使缺失的神经元以正确的数量和比例被替换，以及对于目前的R21应用重要的是，通过建立适当的突触连接将新神经元整合到视网膜回路中。斑马鱼已经成为获得视网膜再生过程知识的关键模型系统-将再生策略应用于哺乳动物视网膜所需的知识。我们先前的研究表明，斑马鱼的再生视网膜在功能上支持基本反射和位置偏好行为，尽管再生视网膜层的紊乱和再生视网膜在每个层内重建视网膜神经元的正常二维图案的失败。这些研究表明，即使在受损和再生视网膜的破坏环境中，再生的视网膜神经元也可以准确地“重新布线”。最终，了解视网膜电路重新布线的机制将是重要的。然而，在我们研究任何机制之前，有必要对再生过程中的重新布线过程以及天然突触连接的成功重现程度进行更完整的描述。因此，在这个R21应用程序中，我们提出了一个详细的研究，在未受损，再生和再生视网膜的斑马鱼的突触连接。我们将集中在视网膜双极细胞的连接体，从而允许内部和外部视网膜电路的分析，通过创新性地使用几个 遗传和分子工具可用于可视化这种视网膜细胞类型及其突触。将检验两个假设：1）再生视网膜的视网膜双极细胞连接体重现了未受损的成人视网膜的连接体; 2）神经突重组与视网膜再生期间的准确重新布线相关。

 DESCRIPTION (provided by applicant): Retinal degenerative diseases and retinal trauma in humans cause progressive loss of retinal neurons and result in decreased visual function, in part because the mammalian retina does not intrinsically respond to the loss of neurons through the generation of replacement neurons. The NEI recently declared its Audacious Goal, to "regenerate neurons and neural connections in the eye and visual system." This goal may be accomplished by developing strategies for activating endogenous retinal cells to manifest regenerative properties, and/or by transplanting replacement retinal neurons or their progenitors from exogenous sources. Challenges to achieving this Audacious Goal include identification of mechanisms for the activation of endogenous cells in mammals, establishment of retinal progenitors such that the missing neurons are replaced in correct numbers and ratios, and importantly for the present R21 application, integration of new neurons into retinal circuitry through the establishment of appropriate synaptic connections. The zebrafish has emerged as a critical model system for gaining knowledge of the retinal regenerative process - knowledge required for applying regenerative strategies to the mammalian retina. Our prior studies indicated that the regenerated retina of the zebrafish functionally supports basic reflexes and place preference behaviors, despite disorganization of the regenerated retinal laminae and failure of regenerated retina to re-establish normal two- dimensional patterns of retinal neurons within each lamina. These studies suggest that regenerating retinal neurons may "re-wire" themselves accurately even in the disrupted environment of the damaged and regenerating retina. Ultimately it will be important to understand the mechanisms through which re-wiring of retinal circuitry takes place. However, before we pursue any mechanisms it is necessary to generate a more complete picture of the re-wiring process during regeneration and the extent of successful recapitulation of native synaptic connections. In this R21 application we therefore propose a detailed study of the synaptic connections in undamaged, regenerating, and regenerated retinas of the zebrafish. We will focus on connectomes of retinal bipolar cells, thus permitting the analysis of inner and outer retinal circuitry, through the innovative use of several genetic and molecular tools available for the visualization of this retinal cell type and its synapses. Two hypotheses will be tested: 1) that retinal bipolar cell connectomes of regenerated retina recapitulate those of undamaged adult retina; and 2) that neurite reorganization is associated with accurate re- wiring during retinal regeneration.