Cellular Interactions with Thrombospondin

细胞与血小板反应蛋白的相互作用

基本信息

批准号：
8554028
负责人：
david d roberts
金额：
$ 84.66万
依托单位：
DIVISION OF CLINICAL SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/8554028
关键词：
Accounting Acute Adverse effects Aging Angiogenesis Inhibition Angiogenesis Inhibitors Autophagocytosis Autophagosome Blood Platelets Blood Pressure Blood Vessels Blood flow Bone Marrow CD47 gene Cardiovascular system Cell Death Cell Surface Receptors Cell Survival Cells Cessation of life Chronic Disease Cyclic GMP Cyclic GMP-Dependent Protein Kinases Data Disease Electron Microscopy Endothelial Cells Enzymes Exhibits Exposure to Extracellular Matrix Proteins Family suidae Gene Expression Genes Glycoproteins Growth Factor Hemostatic function Homeostasis Immune response Immunity Injury Ionizing radiation Ischemia Knockout Mice Ligands Malignant Neoplasms Mediating Membrane Mitochondria Mus Neoplasm Metastasis Nitric Oxide Nitric Oxide Pathway Pathogenesis Pathway interactions Phenotype Physiological Play Proteins Radiation Radiation Injuries Radioprotection Rattus Recovery Regulation Relative (related person)Reperfusion Injury Reporting Research Role Route Signal Pathway Signal Transduction Signal Transduction Pathway Small Interfering RNA Smooth Muscle Myocytes Soluble Guanylate Cyclase Stress T-Lymphocyte THBS1 gene Therapeutic Thrombospondin 1 Tissue Survival Tissues Transgenic Mice Tumor Immunity Vascular Endothelial Growth Factor Receptor Vesicle acute stress angiogenesis antiangiogenesis therapy base cell behavior cell type human NOS3 protein inhibition of autophagy mouse model neoplastic cell peptide analog protein aminoacid sequence receptor response response to injury soft tissue therapeutic angiogenesis therapeutic target thrombospondin 2 tumor tumor growth tumor progression tumor xenograft

项目摘要

Matricellular proteins play diverse roles in modulating cell behavior by engaging specific cell surface receptors and interacting with extracellular matrix proteins, secreted enzymes, and growth factors. Studies of such interactions involving thrombospondin-1 have revealed several physiological functions and roles in the pathogenesis of injury responses and cancer, but the relatively mild phenotypes of mice lacking thrombospondin-1 suggested that thrombospondin-1 would not be a central player that could be exploited therapeutically. Recent research focusing on signaling through its receptor CD47, however, has uncovered more critical roles for thrombospondin-1 in acute regulation of cardiovascular dynamics, hemostasis, immunity, and mitochondrial homeostasis. Several of these functions are mediated by potent and redundant inhibition of the canonical nitric oxide pathway. Conversely, elevated tissue thrombospondin-1 levels in major chronic diseases of aging may account for the deficient nitric oxide signaling that characterizes these diseases, and experimental therapeutics targeting CD47 show promise for treating such chronic diseases as well as acute stress conditions that are associated with elevated thrombospondin-1 expression. Accidental or therapeutic exposure to ionizing radiation has severe physiological consequences and can result in cell death. We previously demonstrated that deficiency or blockade of the ubiquitously expressed receptor CD47 results in remarkable cell and tissue protection against ischemic and radiation stress. Antagonists of CD47 or its ligand THBS1/thrombospondin 1 enhance cell survival and preserve their proliferative capacity. However the signaling pathways that mediate this cell-autonomous radioprotection are unclear. We now report a marked increase in autophagy in irradiated T-cells and endothelial cells lacking CD47. Irradiated T cells lacking CD47 exhibit significant increases in formation of autophagosomes comprising double membrane vesicles visualized by electron microscopy and numbers of MAP1LC3A/B+ puncta. Moreover, we observed significant increases in BECN1, ATG5, ATG7 and a reduction in SQSTM1/p62 expression relative to irradiated wild-type T cells. We observed similar increases in autophagy gene expression in mice resulting from blockade of CD47 in combination with total body radiation. Pharmacological or siRNA-mediated inhibition of autophagy selectively sensitized CD47-deficient cells to radiation, indicating that enhanced autophagy is necessary for the prosurvival response to CD47 blockade. Moreover, re-expression of CD47 in CD47-deficient T cells sensitized these cells to death by ionizing radiation and reversed the increase in autophagic flux associated with survival. This study indicates that CD47 deficiency confers cell survival through the activation of autophagic flux and identifies CD47 blockade as a pharmacological route to modulate autophagy for protecting tissue from radiation injury.

基质细胞蛋白通过结合特定的细胞表面受体并与细胞外基质蛋白、分泌酶和生长因子相互作用，在调节细胞行为中发挥多种作用。对涉及血小板反应蛋白-1 的此类相互作用的研究揭示了损伤反应和癌症发病机制中的多种生理功能和作用，但缺乏血小板反应蛋白-1 的小鼠相对温和的表型表明，血小板反应蛋白-1 不会成为可被利用的核心角色治疗上。然而，最近专注于通过其受体 CD47 进行信号传导的研究发现，血小板反应蛋白-1 在心血管动力学、止血、免疫和线粒体稳态的急性调节中发挥着更重要的作用。其中一些功能是通过对典型一氧化氮途径的有效和冗余抑制来介导的。相反，在主要的衰老慢性疾病中，组织血小板反应蛋白-1水平升高可能是导致这些疾病特征的一氧化氮信号传导缺陷的原因，而针对CD47的实验性疗法显示出治疗此类慢性疾病以及与升高相关的急性应激状况的希望。血小板反应蛋白-1 表达。意外或治疗性暴露于电离辐射会产生严重的生理后果，并可能导致细胞死亡。我们之前证明，普遍表达的受体 CD47 的缺陷或阻断可显着保护细胞和组织免受缺血和辐射应激。 CD47 或其配体 THBS1/血小板反应蛋白 1 的拮抗剂可增强细胞存活并保持其增殖能力。然而，介导这种细胞自主辐射防护的信号通路尚不清楚。我们现在报告，受辐射的 T 细胞和缺乏 CD47 的内皮细胞的自噬显着增加。缺乏 CD47 的受辐射 T 细胞表现出自噬体形成显着增加，该自噬体包含通过电子显微镜可见的双膜囊泡和 MAP1LC3A/B+ 斑点的数量。此外，我们观察到相对于受辐射的野生型 T 细胞，BECN1、ATG5、ATG7 表达显着增加，而 SQSTM1/p62 表达减少。我们观察到，CD47 阻断与全身放疗相结合导致小鼠自噬基因表达出现类似的增加。药理学或 siRNA 介导的自噬抑制选择性地使 CD47 缺陷细胞对辐射敏感，表明增强的自噬对于 CD47 阻断的促生存反应是必要的。此外，CD47缺陷型T细胞中CD47的重新表达使这些细胞对电离辐射的死亡敏感，并逆转了与生存相关的自噬通量的增加。这项研究表明，CD47 缺陷通过激活自噬流赋予细胞存活，并确定 CD47 阻断是调节自噬以保护组织免受辐射损伤的药理学途径。