Circadian Rhythm In Cone Photoreceptors: Cellular Mechanisms

视锥细胞感光器的昼夜节律：细胞机制

• 批准号: 8035294
• 负责人: GLADYS Y KO
• 金额: $ 27.2万
• 依托单位: TEXAS A&M UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-04-01 至 2012-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8035294
• 关键词: 1-Phosphatidylinositol 3-Kinase; Actins; Age related macular degeneration; Blindness; Calcium Channel; Cell membrane; Cellular biology; Cessation of life; Characteristics; Circadian Rhythms; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclic GMP; Cytoskeleton; DNA Sequence Rearrangement; Data; Defect; Development; Disease; Elderly; Elements; Event; Future; Gated Ion Channel; Gene Expression; Genes; Goals; Human; Image; Institutes; Knowledge; L-Type Calcium Channels; Lead; Legal Blindness; MEKs; Macular degeneration; Mediating; Medical; Melatonin; Mitogen-Activated Protein Kinases; Molecular; Movement; Mutation; Neurons; Night Blindness; Output; Pathogenesis; Pathway interactions; Periodicity; Phase; Phosphatidylinositols; Phosphotransferases; Photoreceptors; Physiology; Play; Proteins; Regulation; Research; Research Personnel; Retina; Retinal Cone; Retinal Degeneration; Retinal Diseases; Reverse Transcriptase Polymerase Chain Reaction; Role; Signal Pathway; Signal Transduction; Somatostatin; Stream; Techniques; Time; Transfection; United States; Vision; Visual impairment; Western Blotting; Work; base; calmodulin-dependent protein kinase II; circadian pacemaker; density; fovea centralis; immunocytochemistry; inhibitor/antagonist; kinase inhibitor; macula; meetings; neurotransmission; neurotransmitter release; novel; patch clamp; prevent; programs; protein expression; protein transport; voltage

DESCRIPTION (provided by applicant): Macular degeneration is a major cause of visual impairment in the United States and is associated with the death of cone photoreceptors. The pathogenesis and the cellular events responsible for the distortion of central vision in macular degeneration are not understood. Circadian oscillators in retina photoreceptors are known to play important roles in regulating photoreceptor function and physiology, and disruption of these circadian oscillators leads to the death of photoreceptors and could contribute to the pathogenesis of macular degeneration. The objective of the proposed research is to elucidate the signaling pathways from the circadian oscillators leading to the regulation of L-type voltage-dependent calcium channels (VDCCs) in cone photoreceptors, since the L-type VDCCs are essential in regulating neurotransmitter release in the retina. For example, mutation of the L-type VDCC a1f subunit gene causes incomplete congenital stationary night blindness in humans, with a defect in neurotransmission between photoreceptors and second-order neurons. An integrative approach with multiple techniques including electrophysiological patch-clamp recordings, Western immunoblotting, immunocytochemistry with confocal imaging, quantitative real-time RT- PCR and gene transfection, will be used in this application to achieve the following four specific aims: Specific Aim 1. Characterize the circadian rhythmicity of VDCCs in chick cone photoreceptors. The circadian rhythmicity of L-type VDCCs at multiple time points throughout the entire circadian day will be characterized in detail. Specific Aim 2. Identify the cellular signaling pathways underlying the circadian regulation of VDCCs. The roles of PKA, MAP kinase, CaMKII and PI3 kinase as output pathways leading to the circadian regulation of VDCCs will be determined. Specific Aim 3. Elucidate the roles of actin cytoskeleton rearrangement and protein trafficking on circadian regulation of VDCCs. Specific Aim 4. Define the cellular mechanisms of the phase-dependent modulation of VDCCs by somatostatin. While somatostatin serves as a VDCC inhibitor in other neurons, it shows both phase-dependent enhancement and inhibition of L-type VDCCs in cones. This project will be among the very first studies to define the circadian regulation of L-type VDCCs and their molecular mechanisms in retina photoreceptors. Understanding the molecular signaling of circadian regulation of retina function may ultimately provide knowledge for developing new strategies to treat retinal diseases, especially age-related macular degeneration, and preventing blindness in the future, which are the long-term goals of the PI.

描述（由申请人提供）：黄斑变性是美国视力障碍的主要原因，并且与视锥细胞的死亡有关。黄斑变性中中央视力扭曲的发病机制和细胞事件尚不清楚。已知视网膜感光器中的昼夜节律振荡器在调节感光器功能和生理学中发挥重要作用，这些昼夜节律振荡器的破坏会导致感光器死亡，并可能导致黄斑变性的发病机制。拟议研究的目的是阐明昼夜节律振荡器导致视锥细胞中 L 型电压依赖性钙通道 (VDCC) 调节的信号通路，因为 L 型 VDCC 对于调节视网膜中的神经递质释放至关重要。例如，L型VDCC a1f亚基基因的突变会导致人类不完全先天性静止性夜盲症，导致光感受器和二级神经元之间的神经传递缺陷。本应用将采用多种技术的综合方法，包括电生理膜片钳记录、蛋白质免疫印迹、共聚焦成像免疫细胞化学、定量实时 RT-PCR 和基因转染，以实现以下四个具体目标： 具体目标 1. 表征鸡锥光感受器中 VDCC 的昼夜节律。将详细描述整个昼夜节律中多个时间点的 L 型 VDCC 的昼夜节律。具体目标 2. 确定 VDCC 昼夜节律调节背后的细胞信号传导途径。 PKA、MAP 激酶、CaMKII 和 PI3 激酶作为导致 VDCC 昼夜节律调节的输出途径的作用将被确定。具体目标 3. 阐明肌动蛋白细胞骨架重排和蛋白质运输对 VDCC 昼夜节律调节的作用。具体目标 4. 定义生长抑素对 VDCC 进行相位依赖性调节的细胞机制。虽然生长抑素在其他神经元中充当 VDCC 抑制剂，但它对视锥细胞中的 L 型 VDCC 表现出相位依赖性增强和抑制作用。该项目将是最早定义 L 型 VDCC 的昼夜节律调节及其在视网膜感光器中的分子机制的研究之一。了解视网膜功能昼夜节律调节的分子信号传导可能最终为开发治疗视网膜疾病（尤其是年龄相关性黄斑变性）的新策略提供知识，并在未来预防失明，这是 PI 的长期目标。