Respiration in vivo in the Retina and RPE

视网膜和 RPE 中的体内呼吸

• 批准号: 10390379
• 负责人: JAMES Bryant HURLEY
• 金额: $ 21.4万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10390379
• 关键词: Animals; Back; Biochemical; Blood; Blood flow; Carbon; Catheters; Choroid; Consumption; Data; Disease; Disease Resistance; Electron Transport; Electrons; Energy Metabolism; Environment; Eye; Fumarates; Glucose; Glycolysis; Grant; Hypoxia; Infusion procedures; Label; Light; Malates; Measures; Mediating; Metabolic; Metabolic Pathway; Methods; Mitochondria; Modeling; Mus; Nutrient; Nutritional; Oxidants; Oxides; Oxygen; Oxygen Consumption; Pathway interactions; Photoreceptors; Physiological; Protocols documentation; Publishing; Reporting; Resistance; Respiration; Retina; Retinal Degeneration; Retinal Pigments; Stress; Structure of jugular vein; Structure of retinal pigment epithelium; Succinates; Testing; Therapeutic; Time; Tissues; Water; base; circadian; clinically significant; experimental study; follow-up; in vivo; mouse model; oxidative damage; photoreceptor degeneration; respiratory

Project Summary/Abstract Metabolic fuels from the choroidal blood must pass through the retinal pigment epithelium (RPE) to reach photoreceptors in the retina. The retina and RPE have unique specialized metabolic features that facilitate this flow of nutrients. In previous studies we showed that the RPE minimizes glycolysis so that more glucose can reach the retina. More recently we showed that the retina, which is hypoxic in the eye of a living animal, transfers electrons from mitochondrial respiration to fumarate to make succinate instead of transferring the electrons to oxygen to make water. We also showed that succinate made and released by the retina can fuel oxygen consumption by the RPE. We have proposed a model for energy metabolism in the vertebrate eye in which succinate transfers reducing power from the hypoxic retina to the oxygen rich RPE. After succinate is oxidized by RPE cells, its carbons can be recycled from the RPE back to the retina to accept more electrons and transfer them to oxygen in the RPE. We reported recently several lines of evidence that support this model for a succinate-mediated metabolic cycle in the eye. The evidence so far is based on ex vivo analyses of healthy, functioning retina and RPE/choroid living tissues. However, it also is important to establish to what extent this metabolic cycle occurs in vivo, i.e. in the eyes of living animals. Recently we established an experimental protocol in which we infuse 13C labeled metabolic fuels including succinate and malate through catheters into the jugular veins of mice. We then measure the time course and steady state levels of incorporation of 13C into metabolites in the retina and RPE/choroid. In Aim 1 of this proposal we will confirm our initial findings that the succinate cycle occurs in vivo and we will optimize the infusion protocols. In Aim 2 we will use in vivo infusion to show how circadian and diurnal cycles influence metabolic flux between the retina and RPE. In Aim 3 we will explore strategies to exploit the succinate cycle to slow degeneration of photoreceptors in mouse models of retinal degeneration.

项目概要/摘要 来自脉络膜血液的代谢燃料必须通过视网膜色素上皮 (RPE) 到达视网膜的感光器。视网膜和 RPE 具有独特的专门代谢功能 促进营养物质流动的功能。在之前的研究中，我们表明 RPE 最大限度地减少糖酵解，以便更多的葡萄糖可以到达视网膜。最近我们表明 活体动物眼睛缺氧的视网膜从线粒体转移电子 呼吸作用为富马酸生成琥珀酸，而不是将电子转移给氧气 造水。我们还表明，视网膜产生和释放的琥珀酸可以提供氧气 RPE 的消耗。我们提出了脊椎动物能量代谢的模型 琥珀酸将还原力从缺氧的视网膜转移到富氧的 RPE。 琥珀酸被 RPE 细胞氧化后，其碳可以从 RPE 回收回到 视网膜接受更多电子并将其转移到视网膜色素上皮中的氧气。 我们最近报告了几条证据，支持琥珀酸介导的这种模型 眼睛的代谢循环。迄今为止的证据是基于对健康、 功能性视网膜和 RPE/脉络膜活组织。然而，同样重要的是要建立 这种代谢循环在体内发生的程度，即在活体动物的眼中。 最近我们建立了一个实验方案，其中我们注入 13C 标记的代谢 通过导管将琥珀酸和苹果酸等燃料注入小鼠的颈静脉。我们然后 测量 13C 掺入代谢物的时间过程和稳态水平 视网膜和 RPE/脉络膜。在本提案的目标 1 中，我们将确认我们的初步发现： 琥珀酸循环发生在体内，我们将优化输注方案。在目标 2 中我们将使用 体内输注以显示昼夜节律和昼夜周期如何影响细胞之间的代谢通量 视网膜和 RPE。在目标 3 中，我们将探索利用琥珀酸循环来减缓 视网膜变性小鼠模型中光感受器的变性。