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

基本信息

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
项目类别：
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&apos 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

项目摘要

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/蛋白质稳态，随着时间的推移不断进化，细胞中进行仔细调节的复杂机制。未折叠蛋白反应（UPR）是一种细胞反应当错误折叠的蛋白质在内质网（ER）中积累时，就会激活应激反应。 UPR 的激活对于正常细胞功能和健康至关重要；然而，长期或长期的普遍定期审议导致炎症加剧和细胞凋亡激活。如果这种情况发生在有丝分裂后细胞中，则组织无法再生。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；例如糖尿病视网膜病变、青光眼、莱伯先天性黑蒙和色素性视网膜炎 (RP)。调查 UPR 导致光感受器变性的作用可以提供对目标的重要洞察寻找治疗视网膜退行性疾病患者的新治疗途径。众所周知，普遍定期审议受到 ER 伴侣 BiP 的调节，BiP 既充当分子伴侣，也清除错误折叠的蛋白质并作为普遍定期审议不同部门的监管者。我们第一次发现酶 Fic 可以通过 BiP 的翻译后修饰（AMPylation/deAMPylation）来调节 UPR。这表明 Fic 介导的 BiP AMPylation 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并改变视网膜和视网膜中的 UPR 激活暴露于连续光线下引发的眼睛层膜。我们已经生成了一种新颖的小鼠模型我们可以研究 Fic 介导的 BiP AMPylation 在哺乳动物视网膜中的精确作用。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，2) 是 Fic-/- 小鼠，易受 UPR 相关损伤处于压力和疾病状态下？该项目的研究结果将开发有价值的工具来监测和在正常生理期间，在哺乳动物视网膜细胞中没有 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的稳态可以为未来潜在的治疗方法提供对细胞靶点的洞察治疗或预防与内质网应激相关的感光细胞死亡和视力丧失。