Cholesterol homeostasis in pathogenesis of DR

DR 发病机制中的胆固醇稳态

• 批准号: 10226319
• 负责人: Julia V Busik
• 金额: $ 37.71万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 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/10226319
• 关键词: Affect; Alcohol consumption; Blood; Blood Circulation; Blood Vessels; Blood-Retinal Barrier; Bone Marrow; CCL2 gene; Cells; Cholesterol; Cholesterol Homeostasis; Choroid; Chronic; Complement; Complement Activation; Coupled; Crystal Formation; Crystallization; 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; Lead; Lipids; Location; Masks; Mediating; Microglia; Mus; Neural Retina; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Patients; Pharmacology; 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; base; cell injury; cellular development; complement pathway; crystallinity; cytokine; diabetic; extracellular; human subject; in vivo; lipid metabolism; macrophage; monocyte; novel; prevent; repaired; retinal damage; tissue preparation; tissue processing

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.

胆固醇稳态和代谢的干扰可能导致高胆固醇 解剖组织中的浓度和胆固醇晶体（CC）的形成。 CC通常是 在传统的组织/免疫组织化学中被忽略为乙醇，用于组织加工， 可以解散它们。这掩盖了CC的存在和潜在的致病性参与 机制。使用无需扫描电子显微镜（SEM） 乙醇脱水步骤，我们确定了视网膜之间“脂质池”中的CC的存在 色素上皮（RPE）和感光体（PR）； ii）在糖尿病鼠中自由循环 血; iii）在糖尿病人类受试者的循环单核细胞中。由于CC非常稳定 生理学上，不容易在体内溶解，它们成为 慢性炎症。 CC被先天免疫系统认可为异物 由于它们的形状，坚定和无法溶解。而且，CC也影响 通过NLRP3炎症体激活炎症。这些小说的初步和出版 研究使我们提出了以下假设（见图1中的示意图）：糖尿病 - 诱导的i）全身胆固醇稳态，ii）血液残留屏障功能；和 iii）SIRT1，LXR和CYP46A1表达会改变视网膜胆固醇稳态导致 关键位置内的CC形成：RPE，PR，单核细胞/巨噬细胞以及循环中 影响内皮。这种CC形成导致细胞内和细胞外完成 NLRP3炎症小体的激活和启动高度激活和释放 破坏促炎性细胞因子，促进DR的发展。为了检验这一假设， 我们提出以下特定目标：AIM1：确定残差的暂时变化 导致CC形成的胆固醇积累。目标2：检验糖尿病的假设 - 在视网膜和IN中诱导的胆固醇积累和CC形成 单核细胞/巨噬细胞会影响细胞内和细胞外完成的激活 触发NLRP3炎性体和IL-1β产生。目标3：检验LXR的假设 α-环糊精将胆固醇激活和直接隔离可以抑制CC诱导的 糖尿病性视网膜和IN中的全体和NLRP3炎性体形成 单核细胞/巨噬细胞细胞，从而防止了DR的慢性感染和发育。 影响：该项目的成功完成将导致确定一个完全新颖的 CC诱导的全联盟和NLRP3炎性组形成的途径可以是 以药理为目标以防止DR。