Analyses of retinal circuits after rod rescue in a mouse model of human blindness

人类失明小鼠模型棒救援后视网膜回路的分析

• 批准号: 9547863
• 负责人: Jeannie Chen
• 金额: $ 52.43万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9547863
• 关键词: Address; Adult; Affect; Age; Area; Biochemical; Blindness; Brain; Cell physiology; Cells; Cessation of life; Closure by clamp; Cyclic GMP; Cyclic Nucleotides; Data; Electrodes; Electron Microscopy; Electrons; Electroretinography; Exhibits; Foundations; Future; Genes; Genetic; Genetic Recombination; Homeostasis; Human; Immunohistochemistry; Injury; Knowledge; Light; Measures; Mediating; Modeling; Morphology; Mus; Outcome; Output; Photophobia; Photoreceptors; Process; Property; Recovery; Recovery of Function; Research; Retina; Retinal; Retinal Degeneration; Retinal Ganglion Cells; Retinitis Pigmentosa; Secondary to; Severities; Signal Transduction; Structure; Suction; Synapses; System; Tamoxifen; Therapeutic Intervention; Time; Vertebrate Photoreceptors; Vision; cell motility; cell type; cyclic-nucleotide gated ion channels; functional restoration; gene correction; gene therapy; human model; light microscopy; mature animal; mouse model; multi-electrode arrays; patch clamp; photoreceptor degeneration; postsynaptic; receptive field; relating to nervous system; response; restoration; retinal rods; signal processing; spatiotemporal; stem cell therapy; synaptic function; transmission process; visual information; visual processing; visual stimulus

Project Summary Rod photoreceptor death is a significant cause of human blindness, and much research effort has been expended towards their rescue or replacement using gene or stem cell therapy. However, rod death is followed by secondary changes in the inner retina such as dendritic remodeling, cell migration, and rewiring. The extent to which this reorganization obstructs the potential for recovery of vision following photoreceptor rescue is not known. The objective of this proposal is to examine signal processing in the affected retina following the genetic rescue of rods. To this end, we have created a mouse model of retinal degeneration caused by loss of expression of the β-subunit of the cyclic nucleotide-gated (CNGβ1) channel, a model for autosomal recessive retinitis pigmentosa in humans. The novelty of this mouse model is that CNGβ1 can be expressed from the endogenous locus in all affected CNGB1-/- rods upon tamoxifen(TX)-inducible Cre- mediated recombination, leading to rod rescue. This proposal utilizes this mouse line to determine the impact of rescuing rod function on retinal signal processing. In Aim 1 we will examine how the structure and function of rod photoreceptors recovers following the restoration of CNGβ1 expression. In particular we will examine the extent of functional recovery when TM is administered in mice with increasing severity of retinal degeneration, as this may identify a critical window for the efficacy of rod recovery and halting further degeneration. In Aim 2 we will examine how the synapse between rods and their primary postsynaptic partner, rod bipolar cells, is reformed following rod rescue. Synapses between rods and rod bipolar cells form retinal circuits that regulate our night vision. Finally, in Aim 3 we will evaluate how rod rescue impacts the function of retinal ganglion cells, which are the sole conduit for signals from the retina to reach higher brain areas. The central hypothesis is that while light sensitivity will recover substantially with rod rescue, some deficits in retinal signaling will persist and worsen at late rescue ages due to secondary changes in retinal circuits. These studies will define the window of opportunity for therapeutic intervention and provide a foundation for future studies aimed at reversing the negative effects of neural remodeling.

项目摘要 视杆细胞死亡是人类失明的一个重要原因， 用基因或干细胞疗法来挽救或替代它们。然而，杆死亡是 随后是内层视网膜的继发性变化，例如树突状重塑、细胞迁移和重新布线。 这种重组在多大程度上阻碍了光感受器损伤后视力恢复的潜力。 救援还不知道。这项建议的目的是检查受影响的视网膜的信号处理 在基因拯救棒之后。为此，我们建立了一个视网膜变性的小鼠模型 由环核苷酸门控（CNGβ1）通道β亚基表达缺失引起， 人类常染色体隐性遗传性视网膜色素变性。这种小鼠模型的新奇在于，CNGβ1可以被 在他莫昔芬（TX）诱导的Cre-1表达后，从所有受影响的CNGB 1-/-杆中的内源性基因座表达。 介导的重组，导致杆拯救。本提案利用这条鼠标线来确定影响 对视网膜信号处理的影响。在目标1中，我们将研究结构和功能 随着CNGβ1表达的恢复，视杆细胞的感光细胞恢复。特别是，我们将研究 当在视网膜病变严重程度增加的小鼠中施用TM时， 退化，因为这可以识别杆恢复和停止进一步恢复的功效的关键窗口。 退化在目标2中，我们将研究杆和它们的初级突触后伙伴之间的突触， 视杆双极细胞在视杆挽救后重新形成。视杆细胞和视杆双极细胞之间的突触形成视网膜 控制我们夜视能力的电路最后，在目标3中，我们将评估棒救援如何影响 视网膜神经节细胞，这是唯一的管道信号从视网膜到达更高的大脑区域。的 中心假设是，虽然光敏感性将通过杆拯救而基本恢复，但视网膜中的一些缺陷， 由于视网膜回路中的继发性变化，信号传导将在晚期抢救年龄持续并恶化。这些 研究将确定治疗干预的机会窗口，并为未来的治疗提供基础。 旨在逆转神经重塑的负面影响的研究。