RPE Energy Metabolism and Cell Phenotype

RPE 能量代谢和细胞表型

• 批准号: 10218680
• 负责人: Douglas E. Vollrath
• 金额: $ 5.2万
• 依托单位: STANFORD UNIVERSITY
• 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 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10218680
• 关键词: Address; Affect; Age; Age related macular degeneration; Aging; Atrophic; Cell Aging; Cells; Characteristics; Choroid; DNA Damage; DNA biosynthesis; Development; Disease; Diurnal Rhythm; Electron Transport; Energy Metabolism; Epithelial; Epithelium; Equilibrium; Eye; FRAP1 gene; Food Energy; Foundations; Generations; Genes; Genetic Transcription; Glucose; Glycolysis; Goals; HGF gene; Homeostasis; Human; Hypertrophy; Individual; Knowledge; Light; Link; Malignant Neoplasms; Mediating; Mesenchymal; Metabolic; Metabolism; Mitochondria; Mitochondrial DNA; Mitotic; Modeling; Morphology; Mus; Mutation; NADH; Nerve; Nonexudative age-related macular degeneration; Oxidative Phosphorylation; Oxygen; Pathway interactions; Phagocytes; Phagocytosis; Pharmacology; Phenotype; Photoreceptors; Production; Proteins; Respiration; Retina; Retinal Diseases; Risk Factors; Series; Severity of illness; Shapes; Sirolimus; Structure of retinal pigment epithelium; Time; Tissues; Variant; Vision; Work; Yeasts; aerobic glycolysis; alternative oxidase; cell growth; cost; experimental study; glucose metabolism; human model; in vivo; insight; macula; metabolomics; mitochondrial DNA mutation; mouse model; postnatal; response; retinal damage; stem cell differentiation; success; therapy development; transdifferentiation

The retinal pigment epithelium (RPE) is a highly differentiated, post-mitotic cell layer that performs a host of functions critical to retinal homeostasis. To discharge its many functions, the RPE requires ample energy. Studies of cultured RPE cells show that they can derive energy from glucose by either aerobic glycolysis or oxidative phosphorylation (OXPHOS), depending upon culture conditions. However, the balance between these two primary modes of RPE glucose metabolism in vivo is unknown, and it is unclear whether alterations in this balance occur under normal and/or disease conditions. Abundant evidence links changes in cellular energy metabolism with alterations in cell phenotype in a variety of fields including cancer, development, stem cell differentiation and aging. In the outer retina, mutations in mitochondrial DNA that compromise OXPHOS cause macular retinopathy. Moreover, disproportionate damage to mitochondrial DNA has been documented in the RPE of individuals with age-related macular degeneration (AMD), suggesting a causal link. We previously showed that postnatal loss of mitochondrial DNA and OXPHOS capacity in the murine RPE in vivo has surprising effects on cell phenotype, causing activation of cell growth pathways, increased glycolytic flux, and loss of epithelial functions and integrity. Our findings demonstrate that enforced changes in cellular energy metabolism in vivo can drive dedifferentiation and transdifferentiation of the RPE, and support a causal connection between diminished RPE OXPHOS capacity and AMD. However, our results raise new questions about how particular aspects of altered cellular energy metabolism read out as changes in cell phenotype. Can increased aerobic glycolysis alone, in the presence of intact OXPHOS, activate cell growth pathways, cause dedifferentiation/transdifferentiation and loss of epithelial integrity? Are features of the RPE glycolytic phenotype reversible through rebalancing of metabolism? What aspects of the altered phenotype of OXPHOS- deficient RPE result from lack of ATP production via OXPHOS versus loss of electron transport to oxygen? Does diurnal variation in energy metabolism affect the capacity of the RPE to phagocytize outer segment tips? We propose an ensemble of experiments to address these questions. Specifically we will modulate RPE aerobic glycolysis in vivo in the context of intact OXPHOS, restore respiration without ATP generation to OXPHOS-deficient RPE in vivo, and probe the relationship between RPE energy metabolism and diurnal phagocytic capacity. Through detailed characterization and quantification of the alterations in RPE cell phenotype caused by these in vivo metabolic changes, we will uncover mechanistic connections between energy metabolism and RPE cell phenotype. Because we will work in vivo, the impact of RPE metabolic modulation on photoreceptors will be apparent. Thus, success of this project will not only provide foundational knowledge of in vivo RPE metabolism and its relationship to cell phenotype, it will also inform studies of abnormal RPE metabolism in human retinal disease.

视网膜色素上皮（RPE）是一种高度分化的有线后细胞层，可执行大量宿主 对视网膜稳态至关重要的功能。要释放其许多功能，RPE需要充足的能量。 对培养的RPE细胞的研究表明，它们可以通过有氧糖酵解或 氧化磷酸化（OXPHOS），具体取决于培养条件。但是，在 RPE葡萄糖代谢在体内的这两种主要模式尚不清楚，目前尚不清楚改变是否发生变化 在这种平衡下，在正常和/或疾病状况下发生。大量证据联系了细胞的变化 能量代谢随着各种领域的细胞表型改变，包括癌症，发育，茎 细胞分化和衰老。在视网膜外，线粒体DNA中的突变损害了oxphos 引起黄斑视网膜病。此外，已经记录了对线粒体DNA的不成比例损害 与年龄相关的黄斑变性（AMD）的个体的RPE，提示有因果关系。我们以前 表明线粒体DNA的产后丧失和体内鼠RPE中的oxphos容量 对细胞表型的令人惊讶的影响，导致细胞生长途径的激活，糖酵解通量增加和 上皮功能和完整性的丧失。我们的发现表明，蜂窝能量的变化 体内代谢可以推动RPE的去分化和转变，并支持因果关系 RPE OXPHOS容量减小与AMD之间的联系。但是，我们的结果提出了新问题 关于随着细胞表型的变化的变化，细胞能代谢改变的特定方面是如何读出的。能 在存在完整的Oxphos的情况下，单独增加了有氧糖酵解，激活细胞生长途径，导致 去分化/转分化和上皮完整性的丧失？是RPE糖酵解的特征 通过新陈代谢的重新平衡而可逆的表型？ Oxphos-的改变表型的哪些方面 RPE不足是由于缺乏ATP产生的AXPHOS而导致的，而不是电子传输到氧气的损失？ 能量代谢的昼夜变化是否会影响RPE吞噬外部段尖端的能力？ 我们提出了一组实验，以解决这些问题。具体而言，我们将调制RPE 在完整的Oxphos的情况下，有氧糖酵解在体内，恢复呼吸，而无需ATP生成 缺乏Oxphos的RPE体内，并探测RPE能量代谢与昼夜之间的关系 吞噬能力。通过详细的表征和量化RPE单元格中的变化 这些体内代谢变化引起的表型，我们将发现机械连接 能量代谢和RPE细胞表型。因为我们将在体内工作，所以RPE代谢的影响 对光感受器的调节将是显而易见的。因此，该项目的成功不仅将提供基础 了解体内RPE代谢及其与细胞表型的关系，它也将为您的研究提供信息 人类视网膜疾病中的RPE代谢异常。