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/蛋白质稳态，随着时间的推移已经进化到具有 细胞中有复杂的机制来进行仔细的调节。未折叠蛋白反应（UPR）是一种细胞免疫反应。 当错误折叠的蛋白质在内质网（ER）中积累时激活的应激反应。 UPR的激活对于正常的细胞功能和健康至关重要;然而，慢性或长期的UPR 导致炎症升高和细胞凋亡的激活。如果这发生在有丝分裂后的细胞中， 无法再生。因此，当这种情况发生在视网膜的感光神经元中时，它会引起不可逆的 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先天性黑蒙和视网膜色素变性（RP）。调查 UPR导致光感受器退化的作用可以提供重要的靶点 用于治疗视网膜退行性疾病患者的新治疗途径。众所周知，普遍定期审议 由ER分子伴侣BiP调节，BiP作为分子伴侣清除错误折叠的蛋白质 并作为普遍定期审议不同分支的监管机构。我们第一次发现Fic酶 可以通过BiP的翻译后修饰（AMP化/去AMP化）调节UPR。这 表明Fic介导的BiP的AMP化充当UPR的分子变阻器。为了支持这一点，我们 发现果蝇中fic的缺失会导致视力缺陷和视网膜和视网膜中UPR激活的改变， 由于暴露在连续的光线下而触发的眼睛的板层。我们已经产生了一种新的小鼠模型， 从而我们可以研究Fic介导的BiP AMPylation在哺乳动物视网膜中的确切作用。我们 假设通过BiP的Fic AMPylation调节UPR对于防止光感受器死亡是必要的 和视力丧失。我们将解决以下问题：1）Fic-/-小鼠是否表现出改变的UPR激活， 正常生理条件下的视网膜，和2）Fic-/-小鼠倾向于UPR相关的损伤 在压力和疾病状态下？该项目的研究结果将为监测和 在哺乳动物视网膜细胞中不存在Fic的情况下定义UPR， 老化和视网膜变性疾病状态。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点的深入了解，用于潜在的未来治疗， 治疗或预防ER应激相关的感光细胞死亡和视力丧失。