Respiration in vivo in the Retina and RPE

视网膜和 RPE 中的体内呼吸

• 批准号: 10190455
• 负责人: JAMES Bryant HURLEY
• 金额: $ 26.48万
• 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 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10190455
• 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.

项目摘要/摘要 脉络膜血液中的代谢燃料必须穿过视网膜色素上皮（RPE） 到达视网膜中的光感受器。视网膜和RPE具有独特的专业代谢 促进这种营养流动的特征。在先前的研究中，我们表明RPE 最小化糖酵解，使更多的葡萄糖可以到达视网膜。最近我们表明 视网膜在活动物的眼中缺氧，从线粒体传输电子 呼吸对富马酸盐的呼吸以使琥珀酸酯而不是将电子转移到氧气中 做水。我们还表明，视网膜制造和释放的琥珀酸酯可以燃料氧气 RPE消费。我们提出了脊椎动物中能量代谢的模型 琥珀酸酯将功率从缺氧视网膜降低到富含氧气的RPE的眼睛。 琥珀酸酯被RPE细胞氧化后，其碳碳可以从RPE回收到 视网膜接受更多的电子，并将其转移到RPE中的氧气中。 我们最近报告了几条证据，这些证据支持该模型用于琥珀酸酯介导的 眼睛中的代谢周期。到目前为止，证据是基于对健康的实体分析 功能性视网膜和RPE/脉络膜活性组织。但是，建立 这种代谢周期在体内发生在多大程度上，即在活动物的眼中。 最近，我们建立了一个实验方案，在该方案中注入13C标记的代谢 包括琥珀酸盐和苹果酸在内的燃料通过导管进入小鼠的颈静脉。然后我们 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 琥珀酸酯周期发生在体内，我们将优化输注方案。在AIM 2中，我们将使用 体内输注以表明昼夜节律如何影响 视网膜和RPE。在AIM 3中，我们将探索利用琥珀酸酯周期减速的策略 视网膜变性小鼠模型中光感受器的变性。