Retinal Neuronal Signaling in Early Diabetes

早期糖尿病的视网膜神经信号

• 批准号: 10295911
• 负责人: ERIKA D. EGGERS
• 金额: $ 37.74万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10295911
• 关键词: Address; Affect; Amacrine Cells; Anatomy; Animal Model; Blindness; Blood Vessels; Brain; Buffers; Cell Death; Cells; Complement; Contrast Sensitivity; Development; Diabetes Mellitus; Diabetic Retinopathy; Disease; Dopamine; Dopamine Receptor; Electrophysiology (science); Electroretinography; Functional disorder; Future; Ganglia; Goals; Grant; In Situ Hybridization; In Vitro; Individual; Knowledge; Label; Lead; Light; Light Adaptations; Measurement; Measures; Mediating; Neurons; Output; Pathway interactions; Physiological; Retina; Rod; Role; Signal Pathway; Signal Transduction; Stimulus; Streptozocin; Testing; Time; Vertebrate Photoreceptors; Vision; Visual; Work; diabetic; diabetic patient; gamma-Aminobutyric Acid; ganglion cell; human model; mouse model; neurotransmission; optogenetics; prevent; receptor; receptor expression; receptor sensitivity; relating to nervous system; response; retinal adaptation; retinal damage; retinal neuron; retinal rods; targeted treatment

Project Summary Diabetic retinopathy is a disease of both neurons and vasculature in the retina. Visual function deficits and neuronal retinal dysfunction from electroretinograms, are some of the earliest identifiable diabetic retinal problems, especially in the dim light activated rod pathways. Dysfunction of the inner retina - bipolar cells that receive rod input, ganglion cells that receive bipolar cell input and amacrine cells that modulate this pathway- is tied to the development of serious diabetic retinal problems. We have shown deficits in light-evoked responses of rod pathway inner retinal neurons that are not due to cell death, but the neuronal mechanisms that cause these deficits are unknown and the focus of this proposal. We will identify how a loss in dopamine and Ca2+ signaling in the inner retina impacts light evoked vision loss, and we will modulate these pathways to determine if they can be future targets for preventing diabetic retinal dysfunction and the neuronal progression of vision loss. Dopamine is released by dopaminergic amacrine cells to allow retinal adaptation to increasing background light levels and GABA release from other amacrine cells modulates the timing and spatial sensitivity of ganglion cells, increasing the sensitivity of vision to small stimuli. Using a mouse model of STZ induced diabetes we have shown that dopamine receptor sensitivity and light adaptation in one type of ganglion cell and Ca2+ signaling in amacrine cells in the rod pathway are reduced, suggesting that ganglion cell output to the brain is altered leading to diabetic visual deficits. We will use our expertise in analyzing retinal signaling to determine the roles of dopamine and Ca2+ signaling changes in the diabetic retina using physiological signaling, genetically modified mouse models and optogenetic stimulation. In Aim 1 we will determine if the diabetes induced reduction in dopamine levels reduces dopamine receptor sensitivity of the inner retina in the rod pathway, using single cell electrophysiology recordings of the responses of rod bipolar cells and ganglion cells to light and immunohistochemical and in situ hybridization analysis. In Aim 2 we will determine if the release and retinal function of dopamine in light adaptation are reduced in diabetes, using recordings of physiological responses to increasing background light levels at the single cell level, in vitro ERGs and direct dopamine release measurements. In Aim 3 we will determine what diabetes induced changes in amacrine cell Ca2+ signaling cause reduced rod pathway inhibition by stimulating multiple amacrine cell inputs to the rod pathway directly either electrically or optogenetically and blocking specific components of Ca2+ signaling. These proposed studies will significantly expand our understanding of the mechanisms and progression of early diabetic retinal neuronal damage and are part of our long term goal to develop targets for therapeutics to intervene at an early time point of diabetic retinal damage and augment or complement existing treatments to prevent the neuronal progression of vision loss.

项目摘要 糖尿病性视网膜病是视网膜中神经元和脉管系统的一种疾病。视觉功能缺陷和 电图图的神经元视网膜功能障碍是最早可识别的糖尿病性视网膜 问题，尤其是在昏暗的光线激活杆途径中。内部视网膜 - 双极细胞的功能障碍 接收杆输入，接收双极细胞输入的神经节细胞和无链氨麦细胞，这些细胞调节该途径 - 与严重的糖尿病性视网膜问题的发展有关。我们已经显示出光诱发的缺陷 杆途径的反应不是由于细胞死亡而导致的，而是神经元机制 这是因为这些赤字是未知的，也是该提议的重点。我们将确定多巴胺的损失 内部视网膜中的Ca2+信号传导会影响诱发的视力丧失，我们将调整这些途径 确定它们是否可以是预防糖尿病性视网膜功能障碍和神经元进展的未来目标 视力丧失。多巴胺能释放多巴胺能力氨基氨酸细胞，以使视网膜适应性增加 背景光级别和GABA从其他无合一开始细胞释放，调节时间和空间 神经节细胞的敏感性，提高了视力对小刺激的敏感性。使用STZ的鼠标模型 诱导糖尿病我们已经表明多巴胺受体的灵敏度和一种类型的光适应性 杆途径中的无链氨酸细胞中的神经节细胞和Ca2+信号传导减少了，表明神经节细胞 大脑输出会导致糖尿病视觉缺陷。我们将使用我们的专业知识来分析视网膜 信号传导确定多巴胺和Ca2+信号传导在糖尿病视网膜中的作用 生理信号传导，转基因的小鼠模型和光遗传刺激。在目标1中，我们将 确定糖尿病是否诱导多巴胺水平降低会降低多巴胺受体的敏感性 杆途径中的内部视网膜，使用杆双极反应的单细胞电生理记录 细胞和神经节细胞以照明和免疫组织化学和原位杂交分析。在目标2中，我们将 使用糖尿病中多巴胺在光适应中的释放和视网膜功能是否减少 对单细胞水平上背景光水平增加的生理反应记录，体外ERGS 和直接多巴胺释放测量。在AIM 3中，我们将确定哪些糖尿病引起的变化 小氨基细胞Ca2+信号传导通过刺激多个无链氨酸细胞输入而导致杆途径抑制作用降低 直接在电气或光遗传学上直接进入杆途径，并阻止Ca2+的特定组件 信号。这些拟议的研究将大大扩展我们对机制和 早期糖尿病性视网膜神经元损害的进展，是我们长期目标的一部分 在糖尿病性视网膜损伤的早期点进行干预的治疗剂，并补充现有 治疗以防止视力丧失的神经元进展。