Regulation of the anti-angiogenic switch by CD36, Thrombospondin, and HRGP

CD36、血小板反应蛋白和 HRGP 调节抗血管生成开关

• 批准号: 7524585
• 负责人: Roy L Silverstein
• 金额: $ 39.25万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-20 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7524585
• 关键词: Address; Angiogenesis Inhibitors; Angiogenic Factor; Angiogenic Proteins; Angiogenic Switch; Binding; Biological; Blood; Blood Vessels; Blood capillaries; CD36 gene; Cell Line; Cells; Development; Diabetes Mellitus; Diabetic Retinopathy; Disease; Down-Regulation; Endothelial Cells; Genes; Goals; Growth; Human; In Vitro; Inflammation; Laboratories; Lead; Ligands; Lysophospholipids; Malignant Neoplasms; Measures; Mediating; Messenger RNA; Mus; Myocardial Infarction; NMR Spectroscopy; Organism; Phospholipids; Phosphorylation; Post-Translational Protein Processing; Process; Protein Kinase C; Protein Overexpression; Proteins; Public Health; Radiation; Regulation; Regulatory Pathway; Role; Signal Transduction; Skin; Stroke; Surface; System; Thrombospondin 1; Thrombospondins; Tissues; Transgenic Mice; Transgenic Organisms; Ultraviolet B Radiation; Ursidae Family; angiogenesis; base; design; histidine-rich glycoprotein; human disease; in vivo; lysophosphatidic acid; novel therapeutics; prognostic; receptor; recombinant peptide; response; tumor growth

DESCRIPTION (provided by applicant): The goal of this proposal is to understand the mechanisms by which angiogenesis (new blood vessel growth) is regulated by a protein receptor called CD36 that is expressed on the surface of microvascular endothelial cells. These are the cells that form the lining of blood capillaries. Angiogenesis is a critically important process in the development of many human diseases, including heart attack stroke, diabetes and cancer. Therefore, understanding how the body normally turns angiogenesis on and off has direct potential to lead to new therapeutic and prognostic approaches to many diseases. CD36 functions by sending a signal to microvascular endothelial cells to halt angiogensesis when it is exposed to any of a group of other proteins that contain a structural domain called the thrombospondin type I repeat (TSR). Our laboratory has recently disovered that a protein circulating in blood, called HRGP, bears structural similarity to CD36 and can act as a "decoy", blocking the activity of TSR-containing anti-angiogenic proteins. These discoveries have led to the hypothesis that angiogenesis is modulated by the fine control of CD36, TSR and HRGP expression in tissues. To address the hypothesis three specific aims have been developed. The first is to identify the structural determinants involved in recognition of TSR domains by CD36 and to characterize modulation of TSR binding by oxidized phospholipids. The approach will involve generating recombinant peptides, studying their interaction, and using NMR spectroscopy to define the mechanisms of the interactions at the atomic level. Aim 2 will characterize expression of CD36 in human microvascular endothelial cells, focusing on the mechanisms by which CD36 expression or function is down-regulated by modified phospholipids via protein kinase C activation and by ecto-domain phosphorylation. Expression will be measured at the mRNA and protein levels. The biological importance of these regulatory pathways in vivo will be determined in aim 3, in which angiogenesis associated with UVB skin radiation and tumor growth will be studied in mice with targeted deletion of the cd36 and hrgp genes and transgenic mice that over-express HRGP in skin. Accomplishing these aims could lead to new therapeutic approaches to modulate angiogenesis through the CD36-mediated anti-angiogenic switch. PUBLIC HEALTH RELEVANCE: Angiogenesis (new blood vessel growth) is a critically important process in the development of many human diseases, including heart attack, stroke, diabetic retinopathy, and cancer. Therefore, understanding how the body normally turns angiogenesis on and off has direct potential to lead to new therapeutic and prognostic approaches to many diseases. This project seeks to understand the cellular mechanisms by which an anti-angiogenic switch on blood vessel lining cells (endothelial cells) is turned on and off. The switch is mediated by a cellular receptor called CD36 which functions by sending a signal to endothelial cells to halt angiogenesis when it is exposed to any of a group of other proteins that contain a structural domain called the thrombospondin type I repeat (TSR). This project will define the structural basis of TSR- CD36 interactions, determine how expression of the key components of the system are regulated, and determine the functional role of the system in regulating angiogenesis during inflammation and tumor growth in vivo.

描述（由申请人提供）：本提案的目的是了解微血管内皮细胞表面表达的称为CD 36的蛋白受体调节血管生成（新血管生长）的机制。这些细胞形成毛细血管的内层。血管生成在许多人类疾病的发展中是一个至关重要的过程，包括心脏病发作、中风、糖尿病和癌症。因此，了解身体如何正常地开启和关闭血管生成具有直接的潜力，导致许多疾病的新的治疗和预后方法。CD 36通过向微血管内皮细胞发送信号来发挥作用，当它暴露于包含称为血小板反应蛋白I型重复序列（TSR）的结构域的一组其他蛋白质中的任何一种时，阻止血管生成。我们实验室最近发现，血液中循环的一种蛋白质，称为HRGP，与CD 36具有结构相似性，可以作为“诱饵”，阻断含有TSR的抗血管生成蛋白的活性。这些发现导致了这样的假设，即血管生成是通过精细控制组织中的CD 36、TSR和HRGP表达来调节的。为了解决这一假设，制定了三个具体目标。第一个是确定的结构决定因素参与识别的TSR域的CD 36和表征调制的氧化磷脂的TSR结合。该方法将涉及产生重组肽，研究它们的相互作用，并使用NMR光谱来定义原子水平上的相互作用机制。目的2将表征CD 36在人微血管内皮细胞中的表达，重点是通过修饰的磷脂通过蛋白激酶C活化和胞外结构域磷酸化下调CD 36表达或功能的机制。将在mRNA和蛋白质水平上测量表达。这些调节途径在体内的生物学重要性将在目标3中确定，其中将在cd 36和hrgp基因靶向缺失的小鼠和皮肤中过表达HRGP的转基因小鼠中研究与UVB皮肤辐射和肿瘤生长相关的血管生成。实现这些目标可能会导致新的治疗方法，通过CD 36介导的抗血管生成开关调节血管生成。公共卫生相关性：血管生成（新血管生长）是许多人类疾病（包括心脏病发作、中风、糖尿病视网膜病变和癌症）发展中的一个至关重要的过程。因此，了解身体如何正常地开启和关闭血管生成具有直接的潜力，导致许多疾病的新的治疗和预后方法。该项目旨在了解血管衬里细胞（内皮细胞）上的抗血管生成开关打开和关闭的细胞机制。该开关由称为CD 36的细胞受体介导，其通过向内皮细胞发送信号来发挥作用，当其暴露于包含称为血小板反应蛋白I型重复序列（TSR）的结构域的任何其他蛋白质时，停止血管生成。该项目将定义TSR-CD 36相互作用的结构基础，确定系统关键组分的表达如何调节，并确定系统在体内炎症和肿瘤生长期间调节血管生成的功能作用。