Regulation of retinal homeostasis and disease by Fic-mediated AMPylation

Fic 介导的 AMPylation 对视网膜稳态和疾病的调节

• 批准号: 10741035
• 负责人: Amanda Kathleen Casey
• 金额: $ 45.1万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10741035
• 关键词: ATF6 gene; Acute; Affect; Age; Aging; Apoptosis; Blindness; Cell Death; Cell physiology; Cell surface; Cells; Cellular Morphology; Cellular Stress; Cessation of life; Chronic; Defect; Diabetic Retinopathy; Disease; Disease Progression; Drosophila genus; Endoplasmic Reticulum; Enzymes; Event; Excision; Exhibits; Exposure to; Eye; Eye diseases; Future; GRP78 gene; Glaucoma; Goals; Health; Homeostasis; Image; Inflammation; Investigation; Leber' s amaurosis; Light; Link; Mediating; Modeling; Modification; Molecular; Molecular Chaperones; Molecular Target; Monitor; Mus; Mutation; Natural regeneration; Neurons; Normal tissue morphology; Patients; Photoreceptors; Phototransduction; Physiological; Play; Post-Translational Protein Processing; Process; Proteins; Recovery; Regulation; Reporter; Research; Retina; Retinal Degeneration; Retinal Diseases; Retinitis Pigmentosa; Role; Signal Transduction; Stress; Structure; System; Testing; Therapeutic; Time; Tissues; Transgenes; Vision; Visual; biological adaptation to stress; cell type; cellular targeting; endoplasmic reticulum stress; insight; misfolded protein; mouse model; neurotransmission; new therapeutic target; novel; novel therapeutics; pharmacologic; photoreceptor degeneration; postmitotic; prevent; protein degradation; protein folding; proteostasis; repaired; response; retinal neuron; therapeutic target; tool; visual processing

PROJECT SUMMARY. The proper synthesis, folding, modification and degradation of proteins is vital to cellular health and function. These processes, known collectively as protein homeostasis/proteostasis, have evolved over time to have intricate mechanisms in place for careful regulation in the cell. The unfolded protein response (UPR) is a cellular stress response that is activated when misfolded proteins accumulate in the endoplasmic reticulum (ER). Activation of the UPR is critical for normal cellular function and health; however, a chronic or prolonged UPR results in elevated inflammation and the activation of apoptosis. If this occurs in post-mitotic cells, the tissue cannot be regenerated. Thus, when this occurs in the photoreceptor neurons of the retina, it causes irreversible blindness. Chronic or dysregulated UPR has been linked to a variety of retinal degenerative diseases; such as diabetic retinopathy, glaucoma, Leber congenital amaurosis, and retinitis pigmentosa (RP). Investigation into the role of the UPR that leads to photoreceptor degeneration can provide important insight into targets for novel therapeutic avenues to treat patients with retinal degenerative diseases. The UPR is known to be regulated by the ER chaperone BiP, which acts as both a molecular chaperone to clear misfolded proteins and as a regulator of the different branches of the UPR. We discovered, for first time, that the enzyme Fic can modulate the UPR via post-translational modification (AMPylation/deAMPylation) of BiP. This indicates that Fic-mediated AMPylation of BiP acts as a molecular rheostat for the UPR. In support of this, we found that a loss of fic in Drosophila leads to vision defects and altered UPR activation in the both the retina and lamina of the eye triggered by exposure to continuous light. We have generated a novel mouse model in which we can study the precise role of Fic-mediated BiP AMPylation in the mammalian retina. We hypothesize that the regulation of the UPR via Fic AMPylation of BiP is necessary to prevent photoreceptor death and vision loss. We will address the following questions: 1) do Fic-/- mice exhibit altered UPR activation in the retina under normal physiological conditions, and 2) are Fic-/- mice predisposed to UPR-associated damage under stress and disease states? The findings of this project will develop valuable tools for monitoring and defining the UPR in the absence of Fic in mammalian retinal cells, both during normal physiological aging and in retinal degenerative disease states. Discovering the role Fic plays in the regulation of ER homeostasis in the mammalian retina can provide insight into cellular targets for potential future therapeutics to treat or prevent ER stress-related photoreceptor cell death and vision loss.

项目摘要。 蛋白质的正确合成，折叠，修饰和降解对于细胞健康和功能至关重要。 这些过程统称为蛋白质稳态/蛋白质量，随着时间的流逝而发展为 复杂的机制，以仔细调节细胞。展开的蛋白质反应（UPR）是细胞 当错误折叠的蛋白质积聚在内质网（ER）中时，应激活的应力反应。 UPR的激活对于正常的细胞功能和健康至关重要。但是，慢性或延长UPR 导致炎症升高和凋亡的激活。如果这发生在有丝分裂后细胞中 不能再生。因此，当这种情况发生在视网膜的光感受器神经元中时，它会导致不可逆的 失明。慢性或失调的UPR与多种视网膜退行性疾病有关。例如 糖尿病性视网膜病，青光眼，Leber先天性症和色素性视网膜炎（RP）。调查 导致光感受器变性的UPR的作用可以为目标提供重要的见解 用于治疗视网膜退行性疾病患者的新型治疗途径。已知UPR 受ER伴侣BIP的调节，该BIP既充当分子伴侣，以清除错误折叠的蛋白 并作为UPR不同分支的调节器。我们第一次发现酶FIC 可以通过BIP的翻译后修饰（两座/脱酰化）来调节UPR。这 表明FIC介导的BIP的两座充当UPR的分子风湿病。为此，我们 发现果蝇中FIC的损失会导致视力缺陷，并改变了视网膜和视网膜中的UPR激活 眼睛的薄片是通过暴露于连续光的情况下触发的。我们已经生成了一个新颖的鼠标模型 我们可以研究FIC介导的BIP氨基甲酰化在哺乳动物视网膜中的精确作用。我们 假设通过BIP的FIC对UPR的调节对于预防感光器死亡是必要的 和视力丧失。我们将解决以下问题：1）做FIC - / - 小鼠在 视网膜在正常的生理条件下，2）易于与UPR相关的损伤。 在压力和疾病状态下？该项目的发现将开发出有价值的工具，以监视和 在正常生理期间，在哺乳动物视网膜细胞中不存在FIC的情况下定义UPR 衰老和视网膜退行性疾病状态。发现FIC在ER调节中的作用 哺乳动物视网膜中的稳态可以提供对细胞靶标的潜在疗法的洞察力 治疗或预防与ER应力相关的光感受器细胞死亡和视力丧失。