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：
7969787
负责人：
david d roberts
金额：
$ 87.98万
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/7969787
关键词：
Acute Adhesives Angiogenesis Inhibition Antihypertensive Agents Binding Blocking Antibodies Blood Platelets Blood Vessels Blood flow Breast Carcinoma CD36 gene CD47 gene Cancer Patient Cardiovascular system Cell Surface Receptors Cells Characteristics Clinical Cyclic GMP Data Endothelial Cells Enzymes Epigastric Exhibits Family Future Generations Genes Glycoproteins Goals Growth Human Immune Immune response Immunologic Surveillance In Vitro Inferior Injury Integrins Knockout Mice Ligation Liver Mediating Melanoma Cell Minor Modeling Mus N-terminal Neoplasm Metastasis Nitric Oxide Organ Transplantation Pathway interactions Peptides Perfusion Phorbol Esters Plasminogen Activator Inhibitor 1 Play Radiation Injuries Radioprotection Rattus Recombinants Recovery Regulation Reperfusion Injury Reperfusion Therapy Resistance Role Signal Pathway Signal Transduction Signal Transduction Pathway Smooth Muscle Myocytes Stress Superoxides Therapeutic Thrombospondin 1 Tissues Transgenic Mice Transplantation Tumor Angiogenesis Tumor Immunity Tumor Tissue Vasodilator Agents Wound Healing Xenograft procedure angiogenesis antiangiogenesis therapy base blood pressure regulation cell killing cell type cytotoxic human migration in vivo irradiation killings liver function macrophage melanoma member mouse model neoplastic cell overexpression peptide analog pressure prevent protein aminoacid sequence receptor response response to injury soft tissue success thrombospondin 2 thrombospondin 4 treatment planning tumor tumor growth tumor progression tumor xenograft

项目摘要

New advances in understanding how TSP1 regulates NO signaling this year include discovery that blood pressure regulation and cardiovascular responses to stress are abnormal in TSP1 and CD47 null mice. The null mice exhibit exaggerated hypotensive responses to vasodilators and to autonomic blockade. We showed in the previous year that the absence of TSP1 or CD47 or therapeutic blocking of their interaction enhances tissue recovery from fixed ischemic injuries. We have now extended this to ischemia/reperfusion (I/R) injuries. We showed in mouse liver that tissue damage is minimized by blocking this pathway. Liver function is also preserved in that the characteristic elevation of circulating liver enzymes following ischemia/reperfusion injury can be prevented to antibody blocking of the TSP1/CD47 interaction. This could have therapeutic application in organ transplantation to prevent post-transplantation I/R injuries. We then extended this finding to a rat I/R injury model using temporary ligation of the deep inferior epigastric vessels. Remarkably, protection was seen in this I/R injury even when treatment was delayed until 30 minutes after reperfusion. Because most I/R injuries occur under non-elective conditions, the ability to treat post-injury has obvious clinical advantages. Therapeutic irradiation is an important component of the treatment plan for a majority of cancer patients. Our success in controlling I/R injury responses suggested that TSP1/CD47 signaling may also limit survival of radiation injuries. We found that TSP1 and CD47 null mice are remarkably resistant to soft tissue irradiation. This protection was reproduced in isolated vascular cells from the null mice, indicated that radioprotection is cell-autonomous. Importantly, tumors growing in the null mice were not protected, suggesting that therapeutic blocking of this pathway selectively protects normal but not tumor tissue. It is important to know whether the ability to antagonize NO/cGMP signaling via CD47 is unique to TSP1. Based on peptide binding studies, others have proposed that CD47 recognizes a sequence that is conserved among all 5 members of the thrombospondin family. However, we found using recombinant forms of TSP1, TSP2, and TSP4 that this activity is specific for TSP1. We extended our understanding of immune regulation by TSP1 to macrophages and innate immune responses to tumors. Over-expression of TSP1 in melanoma cells causes delayed growth and increased tumor-associated macrophage (TAM) recruitment into xenograft tumors grown in nude mice74. However, TAM can differentiate into either cytotoxic (M1) or tumor growth-promoting (M2) states. Increased iNOS is a hallmark of M1 macrophages, and although M1 cytotoxic macrophages are a minor fraction of the TAM in a melanoma xenograft, their recruitment or differentiation is increased when those tumors express TSP1. In vitro, TSP1 acutely induces expression of plasminogen activator inhibitor-1 (PAI-1), an important regulator of macrophage migration, by human and mouse macrophages. PAI-1 is strongly expressed by TAM in TSP1-overexpressing tumors in vivo, suggesting that TSP1-induced macrophage recruitment is at least partially mediated by PAI-1. Moreover, TSP1 and TSP2 cause a significant increase in phorbol ester-mediated superoxide generation by M1-differentated human monocytic cells, which mediates tumor cell killing, by interacting with a61 integrin through their NH2-terminal domains. TSP1 stimulates killing of breast carcinoma and melanoma cells by M1-polarized macrophages in vitro via this release of ROS. Taken together, these data suggest that TSP1 plays an important role in innate anti-tumor immunity by enhancing recruitment and activation of M1 TAM. Thus, avoiding this innate immune surveillance could provide an additional selective pressure for loss of TSP1 and TSP2 expression during tumor progression.

今年了解 TSP1 如何调节 NO 信号传导的新进展包括发现 TSP1 和 CD47 缺失小鼠的血压调节和心血管对压力的反应异常。无效小鼠对血管扩张剂和自主神经阻滞表现出过度的低血压反应。我们在前一年证明，TSP1 或 CD47 的缺失或治疗性阻断它们的相互作用可以增强固定缺血性损伤的组织恢复。我们现在已将其扩展到缺血/再灌注 (I/R) 损伤。我们在小鼠肝脏中证明，通过阻断该途径可以最大限度地减少组织损伤。肝功能也得到保留，因为可以通过抗体阻断 TSP1/CD47 相互作用来防止缺血/再灌注损伤后循环肝酶的特征性升高。这可能在器官移植中具有治疗应用，以预防移植后缺血再灌注损伤。然后，我们通过临时结扎腹壁下血管，将这一发现扩展到大鼠 I/R 损伤模型中。值得注意的是，即使治疗延迟到再灌注后 30 分钟，这种 I/R 损伤也能发挥保护作用。由于大多数 I/R 损伤发生在非选择性条件下，因此伤后治疗能力具有明显的临床优势。 治疗性放射治疗是大多数癌症患者治疗计划的重要组成部分。我们在控制 I/R 损伤反应方面的成功表明，TSP1/CD47 信号传导也可能限制辐射损伤的生存。我们发现 TSP1 和 CD47 缺失小鼠对软组织辐射具有显着的抵抗力。这种保护作用在来自无效小鼠的分离血管细胞中重现，表明放射保护作用是细胞自主的。重要的是，在无效小鼠中生长的肿瘤没有受到保护，这表明治疗性阻断该途径可以选择性地保护正常组织，但不能保护肿瘤组织。 了解 CD47 是否具有拮抗 NO/cGMP 信号传导的能力非常重要是 TSP1 所独有的。基于肽结合研究，其他人提出 CD47 识别血小板反应蛋白家族所有 5 个成员中保守的序列。然而，我们使用 TSP1、TSP2 和 TSP4 的重组形式发现，这种活性是 TSP1 特有的。 我们将 TSP1 免疫调节的理解扩展到巨噬细胞和对肿瘤的先天免疫反应。黑色素瘤细胞中 TSP1 的过度表达会导致生长延迟，并增加肿瘤相关巨噬细胞 (TAM) 招募到裸鼠异种移植肿瘤中的情况74。然而，TAM 可以分化为细胞毒性 (M1) 或肿瘤生长促进 (M2) 状态。 iNOS 增加是 M1 巨噬细胞的标志，尽管 M1 细胞毒性巨噬细胞只占黑色素瘤异种移植物中 TAM 的一小部分，但当这些肿瘤表达 TSP1 时，它们的募集或分化就会增加。在体外，TSP1 急剧诱导人和小鼠巨噬细胞表达纤溶酶原激活物抑制剂-1 (PAI-1)，这是巨噬细胞迁移的重要调节因子。 PAI-1 在体内 TSP1 过表达肿瘤中由 TAM 强烈表达，表明 TSP1 诱导的巨噬细胞募集至少部分是由 PAI-1 介导的。此外，TSP1和TSP2通过其NH2末端结构域与a61整合素相互作用，导致M1分化的人单核细胞佛波酯介导的超氧化物产生显着增加，从而介导肿瘤细胞杀伤。 TSP1 通过释放 ROS，在体外刺激 M1 极化巨噬细胞杀死乳腺癌和黑色素瘤细胞。总而言之，这些数据表明 TSP1 通过增强 M1 TAM 的募集和激活在先天抗肿瘤免疫中发挥重要作用。因此，避免这种先天免疫监视可能会为肿瘤进展过程中 TSP1 和 TSP2 表达的丧失提供额外的选择性压力。