PAD4 in Retinal Gliosis

PAD4 与视网膜神经胶质增生

• 批准号: 9436900
• 负责人: ROYCE MOHAN
• 金额: $ 19.94万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-02-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9436900
• 关键词: Acute; Adhesions; Affect; Age related macular degeneration; Alkalies; Amidines; Apoptosis; Applications Grants; Arginine; Arginine deiminase; Arthritis; Astrocytes; Blindness; Cell Cycle Proteins; Cells; Characteristics; Chemical Injury; Chronic; Cicatrix; Citrulline; Clinical; Data; Disease; Disease model; Dose; Drug Targeting; Enzyme Inhibitor Drugs; Enzymes; Foundations; Genetic; Glaucoma; Glial Fibrillary Acidic Protein; Gliosis; Human; Immune; Immune System Diseases; Inflammatory; Injury; Investigation; Knock-out; Knowledge; Laser injury; Lasers; Link; Logic; Modeling; Modification; Muller' s cell; Multiple Sclerosis; Mus; Neuroglia; Pathologic; Pathology; Pathway interactions; Peptides; Pharmaceutical Preparations; Phase; Phenotype; Physiological; Play; Post-Translational Protein Processing; Pre-Clinical Model; Prognostic Marker; Proteins; Recovery; Retina; Retinal; Retinal Degeneration; Retinal Detachment; Rheumatoid Arthritis; Role; Site-Directed Mutagenesis; Testing; Time; Translating; Untranslated RNA; arm; attenuation; burden of illness; citrullinated protein; diagnostic biomarker; drug discovery; druggable target; enzyme activity; experimental study; glial activation; high risk; in vivo; inhibitor/antagonist; injured; innovation; insight; interest; new therapeutic target; next generation; overexpression; protein expression; repaired; response; response to injury; selective expression; small molecule; small molecule inhibitor; specific biomarkers

Citrullination is an important protein posttranslational modification (PTM) caused by an irreversible modification of the arginine residues on proteins to the non- coded citrulline residues by the peptidyl arginine deiminase enzymes (PADs). Citrullination is a permanent/irreversible change in numerous critical protein targets, and citrullinated proteins have been detected as disease-specific biomarkers in several major inflammatory diseases, such as rheumatoid arthritis, and multiple sclerosis (MS). Targeting PADs with small molecule inhibitors has been shown to be effective in reducing disease burden in several preclinical models. We have recently demonstrated that citrullination is induced in the mouse retina by alkali injury. Of particular interest is the discovery that activated Muller glia, and retinal astrocytes displayed elevated levels of citrullinated soluble glial fibrillary acidic protein (GFAP). Furthermore, inhibition of citrullination alters expression characteristics of soluble GFAP, and linked PAD's activity to retinal gliosis. We discovered that these increases in the citrullination pathway are found during chronic gliosis induced by severe alkali injury, but reversed in milder alkali burn model. Interestingly, activated Muller glia selectively expressed PAD4, which is responsible for GFAP citrullination, and inhibition of PAD4 reduces soluble GFAP expression. In this R21 grant proposal, we will test the hypothesis that PAD4-driven citrullination controls the chronic gliotic response in the laser injury model of age-related macular degeneration (AMD). In specific Aim 1, we will investigate the dynamics of PAD4 expression during acute versus chronic gliosis, and PAD4's association with overexpression of citrullination, and GFAP's modification(s) in different injury paradigms. In Aim 2, we will investigate the consequence of inhibiting PAD4 enzymatic activity as well as causing PAD4 deficiency in astrocytes/glial cells through conditional target knockout strategy, and investigate how the inhibition/absence of this critical enzyme affects injury response. This approach that focuses on PAD4 will help establish whether PAD4 is druggable in vivo in injury states and for the first time lay down the foundation to probe this druggable target in conditions, such as AMD, that cause irreversible blindness.

瓜氨酸是一种重要的蛋白质翻译后修饰（PTM）， 通过将蛋白质上的精氨酸残基不可逆地修饰为非- 通过肽基精氨酸脱亚胺酶（PAD）编码瓜氨酸残基。 瓜氨酸是许多关键蛋白质的永久/不可逆变化 目标，瓜氨酸化蛋白已被检测为疾病特异性 几种主要炎性疾病，如类风湿性关节炎， 多发性硬化症（MS）用小分子抑制剂靶向PAD， 在几个临床前研究中， 模型我们最近已经证明，瓜氨酸是诱导的， 小鼠视网膜碱损伤。特别令人感兴趣的是， Muller胶质细胞和视网膜星形胶质细胞显示瓜氨酸可溶性 胶质细胞酸性蛋白（GFAP）。此外，瓜氨酸的抑制改变了 可溶性GFAP的表达特征，并将PAD的活性与视网膜的 神经胶质增生我们发现瓜氨酸化途径的这些增加是在 在重度碱损伤诱导的慢性胶质细胞增生过程中， 燃烧模型有趣的是，激活的Muller胶质细胞选择性表达PAD 4， 其负责GFAP瓜氨酸，并且抑制PAD 4降低 可溶性GFAP表达。在这个R21拨款提案中，我们将测试假设 PAD 4驱动的瓜氨酸控制激光中的慢性神经胶质反应， 年龄相关性黄斑变性（AMD）损伤模型。在具体目标1中， 将研究在急性与慢性炎症过程中PAD 4表达的动力学， 神经胶质增生，以及PAD 4与瓜氨酸和GFAP过度表达的关系。 在不同的损伤范例中的修改。在目标2中，我们将研究 抑制PAD 4酶活性以及引起PAD 4 通过条件性靶敲除策略在星形胶质细胞/神经胶质细胞中的缺陷， 并研究这种关键酶的抑制/缺失如何影响损伤 反应这种关注PAD 4的方法将有助于确定PAD 4是否 在体内损伤状态下是可用药的，并首次奠定了基础 在AMD等导致不可逆转的 失明