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Cholesterol homeostasis in pathogenesis of DR

DR 发病机制中的胆固醇稳态

基本信息

批准号：
10693905
负责人：
Julia V Busik
金额：
$ 38.88万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2025-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10693905
关键词：
Affect Arterial Fatty Streak Blood Blood Vessels Blood-Retinal Barrier Bone Marrow CCL2 gene Cells Cholesterol Cholesterol Homeostasis Choroid Chronic Circulation Complement Complement Activation Coupled Crystal Formation Cyclodextrins Cytochrome P450 Dehydration Development Diabetes Mellitus Diabetic Retinopathy Disease Dyslipidemias Endothelium Ethanol Excision Extracellular Space Foreign Bodies Funding Genes Immune system Immunohistochemistry Infiltration Inflammasome Inflammation Inflammation Mediators Inflammatory Innate Immune System Intercellular adhesion molecule 1 Interleukin-1 beta Lectin Lipids Location Macrophage Masks Mediating Microglia Mus Neural Retina Pathogenesis Pathogenicity Pathology Pathway interactions Patients Photoreceptors Physiological Production Prognostic Marker Publishing Repression Retina SIRT1 gene Scanning Electron Microscopy Shapes Source Structure Structure of retinal pigment epithelium Testing Tissues X ray spectroscopy cell injury cellular development complement pathway cytokine diabetic extracellular human subject in vivo lipid metabolism monocyte novel pharmacologic prevent repaired retinal damage tissue preparation tissue processing

项目摘要

Disruptions in cholesterol homeostasis and metabolism can lead to high cholesterol concentrations in diseased tissue and the formation of cholesterol crystals (CC). CC are often overlooked in traditional histo/immunohistochemistry as the ethanol, used for tissue processing, can dissolve them. This masks CC presence and potential involvement in pathogenic mechanisms. Using Scanning Electron Microscopy (SEM) of tissues prepared without an ethanol dehydration step, we identified the presence of CC: i) in “lipid pools” between retinal pigment epithelium (RPE) and photoreceptors (PR); ii) circulating freely in diabetic murine blood; and iii) within circulating monocytes of diabetic human subjects. Since CC are very stable physiologically and are not easily amenable to dissolving in vivo, they become a source of chronic inflammation. CC are recognized by the innate immune system as foreign bodies because of their shape, firmness, and inability to be dissolved. Moreover, CC also induce inflammation via the NLRP3 inflammasome activation. These novel preliminary and published studies have led us to propose the following hypothesis (see schematic in Fig.1): Diabetes- induced disruption of i) systemic cholesterol homeostasis, ii) blood retinal barrier function; and iii) SIRT1, LXR and CYP46A1 expression alters retinal cholesterol homeostasis leading to CC formation within key locations: RPE, PR, monocytes/macrophages, and in the circulation affecting the endothelium. This CC formation results in intra- and extracellular complement activation and priming of the NLRP3 inflammasome for its activation and release of highly damaging pro-inflammatory cytokines, promoting development of DR. To test this hypothesis, we propose the following Specific Aims: Aim1: To determine the temporal changes in retinal cholesterol accumulation that lead to CC formation. Aim 2: To test the hypothesis that diabetes- induced cholesterol accumulation and CC formation in the retina and in monocytes/macrophages induces activation of intracellular and extracellular complement to trigger the NLRP3 inflammasome and IL-1β production. Aim 3: To test the hypothesis that LXR activation and direct sequestration of cholesterol by alpha-cyclodextrin can inhibit CC-induced complosome and NLRP3 inflammasome formation in the diabetic retina and in monocytes/macrophages cells, thus preventing chronic inflammation and development of DR. Impact: The successful completion of this project will result in identifying an entirely novel pathway in which CC-induced complosome and NLRP3 inflammasome formation that can be pharmacologically targeted to prevent DR.

胆固醇稳态和新陈代谢的破坏可能导致高胆固醇患病组织中的浓度和胆固醇晶体 (CC) 的形成。 CC 经常在传统组织/免疫组织化学中被忽视的乙醇，用于组织处理，可以溶解它们。这掩盖了 CC 的存在以及致病性的潜在参与机制。使用扫描电子显微镜 (SEM) 对未制备的组织进行扫描在乙醇脱水步骤中，我们确定了 CC 的存在：i) 在视网膜之间的“脂质池”中色素上皮 (RPE) 和光感受器 (PR)； ii) 在糖尿病小鼠中自由循环血; iii) 糖尿病人类受试者的循环单核细胞内。因为CC非常稳定生理学上并且不易在体内溶解，它们成为慢性炎症。 CC 被先天免疫系统识别为异物因为它们的形状、硬度和无法溶解。此外，CC还诱导通过 NLRP3 炎症小体激活产生炎症。这些小说初稿并出版研究使我们提出以下假设（见图 1 中的示意图）：糖尿病- 诱导破坏 i) 全身胆固醇稳态，ii) 血视网膜屏障功能；和 iii) SIRT1、LXR 和 CYP46A1 表达改变视网膜胆固醇稳态，导致 CC 在关键部位形成：RPE、PR、单核细胞/巨噬细胞以及循环中影响内皮细胞。这种 CC 的形成导致细胞内和细胞外的补体 NLRP3 炎症小体的激活和启动，以激活和释放高度破坏促炎细胞因子，促进 DR 的发展。为了检验这个假设，我们提出以下具体目标：目标 1：确定视网膜的时间变化胆固醇积累导致CC形成。目标 2：检验糖尿病的假设诱导视网膜中的胆固醇积累和CC形成单核细胞/巨噬细胞诱导细胞内和细胞外补体的激活触发 NLRP3 炎性体和 IL-1β 的产生。目标 3：检验 LXR 的假设 α-环糊精对胆固醇的激活和直接隔离可以抑制 CC 诱导的糖尿病视网膜中复合体和 NLRP3 炎症小体的形成单核细胞/巨噬细胞，从而预防慢性炎症和 DR 的发展。影响：该项目的成功完成将导致确定一个全新的 CC 诱导复合体和 NLRP3 炎性体形成的途径药物靶向预防 DR。