Cellular and molecular mechanisms of retinoic acid-mediated blood-retinal barrier regulation

视黄酸介导的血视网膜屏障调节的细胞和分子机制

• 批准号: 9760685
• 负责人: LANA Mary POLLOCK
• 金额: $ 6.37万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-11 至 2021-04-10
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9760685
• 关键词: Adult; Affect; Age related macular degeneration; Amacrine Cells; Attenuated; Binding Proteins; Blindness; Blood; Blood - brain barrier anatomy; Blood Circulation; Blood-Retinal Barrier; Cells; Clinical Trials; Data; Diabetic Retinopathy; Disease; Disease Pathway; Dominant-Negative Mutation; EIF4EBP1 gene; Electroretinography; Endothelial Cells; Eukaryotic Initiation Factors; FRAP1 gene; Fishes; Functional disorder; Gelatinase B; Genes; Genetic; Histology; Homeostasis; Human; Immunohistochemistry; Insulin; Larva; Lead; Leucine; Maintenance; Mediating; Modeling; Molecular; Morphology; Movement; Muller' s cell; Mutation; Neural Retina; Pathology; Pathway Analysis; Pathway interactions; Patients; Pattern; Photoreceptors; Play; Proteins; Regulation; Retina; Retinal; Retinal Ganglion Cells; Retinoic Acid Receptor; Ribosomal Protein S6; Role; Signal Pathway; Signal Transduction; Sirolimus; Structure of retinal pigment epithelium; Tamoxifen; Testing; Therapeutic; Tight Junctions; Tissues; Tretinoin; Vision; Visual; Visual Acuity; Vitamin A; Western Blotting; Zebrafish; age related; cell type; diabetic; differential expression; effective therapy; horizontal cell; inhibitor/antagonist; macular edema; mutant; new therapeutic target; novel therapeutic intervention; prevent; promoter; protein expression; receptor; relating to nervous system; response; retinal damage; tool; transcriptome sequencing; vision development

PROJECT SUMMARY The blood-retinal barrier (BRB) mediates movement of molecules from the blood to the retina, protecting the retinal neural tissue from potentially harmful molecules and maintaining retinal homeostasis. Breakdown of the BRB is associated with ocular diseases such as diabetic retinopathy and age-related macular edema. The BRB consists of both an inner barrier, formed by microvascular endothelial cells, and an outer barrier, formed by the RPE. Tight junctions between these cells are essential to barrier function. However, the molecular mechanisms regulating tight junction integrity in the BRB and the effects of BRB breakdown on retinal morphology and visual function are not fully understood. The zebrafish (Danio Rerio) is an ideal model to investigate the mechanisms of BRB breakdown and maintenance due to its rapid ex vivo visual development and the availability of a wide array of genetic tools. We have recently determined that retinoic acid (RA), a metabolite of Vitamin A, plays a critical role in the maintenance of the BRB. Disruption of RA signaling in zebrafish larvae and adults with a pan-retinoic acid receptor inhibitor (BMS493) results in BRB breakdown, disrupted expression of tight junction proteins in the retinal vasculature and RPE, and decreased visual acuity. Preliminary RNA sequencing and pathway analysis of differentially expressed genes indicates that the mTOR signaling pathway is significantly upregulated in retinas of fish treated with an inhibitor of RA signaling compared to untreated fish. Additionally, inhibition of mTOR signaling by treatment with rapamycin is sufficient to restore BRB integrity in RA-inhibitor-treated larvae. Therefore, we propose that RA maintains the BRB via crosstalk with the mTOR pathway and that RA-inhibitor-induced BRB breakdown leads to retinal damage and visual dysfunction. We will characterize the role of RA and the mTOR signaling pathway in BRB maintenance by assessing the pattern of mTOR activation in the inner and outer BRB and identifying the upstream and downstream regulators involved in BMS493- induced BRB breakdown. We will also determine which cells in the retina contribute to RA-inhibitor- induced BRB breakdown and characterize the cellular changes in the retina in response. Understanding the cellular and molecular mechanisms involved in RA-mediated BRB maintenance and the progression of retinal damage and vision loss following BRB breakdown will be critical to identify therapeutic approaches for preventing vision loss due to BRB disruption.

项目概要 血视网膜屏障（BRB）介导分子从血液到视网膜的运动， 保护视网膜神经组织免受潜在有害分子的侵害并维持视网膜 体内平衡。 BRB 的破坏与糖尿病视网膜病变等眼部疾病有关 和年龄相关性黄斑水肿。 BRB 由微血管形成的内部屏障组成 内皮细胞和由 RPE 形成的外屏障。这些细胞之间的紧密连接是 对屏障功能至关重要。然而，调节紧密连接完整性的分子机制 BRB 以及 BRB 分解对视网膜形态和视觉功能的影响尚不完全 明白了。斑马鱼 (Danio Rerio) 是研究 BRB 机制的理想模型 由于其快速的离体视觉发育和广泛的可用性而导致的故障和维护 一系列遗传工具。我们最近确定视黄酸（RA）是维生素 A 的代谢产物， 在 BRB 的维护中起着至关重要的作用。斑马鱼幼虫中 RA 信号传导的破坏 患有泛视黄酸受体抑制剂 (BMS493) 的成人会导致 BRB 分解、破坏 视网膜血管和 RPE 中紧密连接蛋白的表达，并降低视力。 初步的RNA测序和差异表达基因的通路分析表明 在用抑制剂处理的鱼的视网膜中，mTOR 信号通路显着上调 与未经处理的鱼相比，RA 信号传导。此外，通过治疗抑制 mTOR 信号传导 雷帕霉素足以恢复 RA 抑制剂处理的幼虫中 BRB 的完整性。因此，我们建议 RA 通过与 mTOR 通路串扰维持 BRB，并且 RA 抑制剂诱导 BRB 分解会导致视网膜损伤和视觉功能障碍。我们将描述 RA 的角色和 通过评估 mTOR 激活模式来研究 BRB 维持中的 mTOR 信号通路 内部和外部 BRB 并识别 BMS493 涉及的上游和下游调节器- 诱导 BRB 击穿。我们还将确定视网膜中的哪些细胞有助于 RA 抑制剂 诱导 BRB 分解并表征视网膜中响应的细胞变化。 了解 RA 介导的 BRB 维持所涉及的细胞和分子机制 BRB 崩溃后视网膜损伤和视力丧失的进展对于 确定预防 BRB 破坏导致视力丧失的治疗方法。