Preservation of liver function through modulation of Fas-binding proteins

通过调节 Fas 结合蛋白来保护肝功能

• 批准号: 8333368
• 负责人: FELIPE SAMANIEGO
• 金额: $ 19.75万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-15 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8333368
• 关键词: Antibodies; Apoptosis; Apoptotic; Area; Binding; Binding Proteins; Biological Preservation; Boxing; CD95 Antigens; Cell Death; Cells; Cellular Stress; Cessation of life; Cleaved cell; Clinical; Complex; Dominant-Negative Mutation; Dose; Event; Genetic Transcription; Goals; Hepatocyte; In Situ Nick-End Labeling; Infection; Ionizing radiation; Liver; Liver diseases; Lymphocyte; Maps; Mediating; Mediator of activation protein; Modeling; Mus; Nuclear; Outcome; Pathology; Phenotype; Plasmids; Play; Prevention; Protein Binding; Receptor Activation; Regulation; Research; Role; Signal Transduction; Site; Staining method; Stains; System; Testing; Therapeutic; Tissues; Toxin; Transforming Growth Factors; Tumor Suppressor Proteins; carcinogenesis; caspase-3; cell injury; chemotherapy; irradiation; liver function; mutant; protein function; receptor; reconstitution; response; transcription factor PML

DESCRIPTION (provided by applicant): This project, which builds on our recent observations of regulation of Fas death receptor, takes us to a new area of research, the analysis of liver cells, where Fas plays a critical role mediating liver disorders. Death receptors have key roles in numerous cell death/proliferation decisions. More specifically, the Fas death receptor plays a pivotal role in liver tissue to determine the outcomes of challenges induced by cell stress due to infection and toxins. The Fas system is an important cell elimination system that has several established functions, including the elimination of autoreactive lymphocytes, infected and defective cells and cells damaged by chemotherapy and irradiation. Without the Fas system, for example, in Fas -/- cells, many clinical chemotherapies and ionizing radiation are no longer effective in eradicating cells. Given the common expression of Fas, the common inability to eliminate some cells that express Fas, we suspect Fas to be under tight control. While Fas activation serves as a clinically beneficial mediator of chemotherapy, inadvertent Fas signaling can perpetuate liver damage and death. In this project we searched for potential binding regulators of Fas and identified a tumor suppressor protein promyelocytic leukemia protein (PML), which is associated with enhanced apoptosis. We chose to test the dominant-negative PMLRARa because its phenotype is easier to visualize. We found that PMLRARa (and PML) binds to Fas and potently blocks apoptosis in cells. When express in mouse liver, PMLRARa effectively protects mice from death induced by a lethal dose of agonistic anti-Fas antibody. The B-box domain of PML is necessary for binding to Fas, suggesting that PML and PMLRARa use this site to bind Fas. A model of opposing effects of PML and PMLRARa on regulation of transforming growth factor 2 receptor (TGF2R) has been established and we suspect that Fas operates in a similar model. Our hypothesis is that PML positively regulates Fas signaling, which plays a critical role in death and proliferation decisions. We will use PML dominant-negative mutant PMLRARa as a probe to characterize the blocking effects on Fas. We anticipate that PML will express have Fas-promoting effects and will explain the widely known apoptosis enhancement effect of PML. Our hypothesis is that PML is a binding regulator of Fas and this interaction can be modulated to preserve liver tissue function. The long-term goal of this project is to understand apoptosis regulation of liver cells to reverse liver pathology driven by the Fas receptors.

描述（由申请人提供）：该项目建立在我们最近对 Fas 死亡受体调节的观察基础上，将我们带入一个新的研究领域，即肝细胞分析，其中 Fas 在介导肝脏疾病中发挥着关键作用。死亡受体在许多细胞死亡/增殖决策中发挥关键作用。更具体地说，Fas 死亡受体在肝组织中发挥着关键作用，以确定感染和毒素引起的细胞应激引起的挑战的结果。 Fas系统是一种重要的细胞消除系统，具有多种既定功能，包括消除自身反应性淋巴细胞、感染和缺陷细胞以及化疗和放射损伤的细胞。例如，在 Fas -/- 细胞中，如果没有 Fas 系统，许多临床化疗和电离辐射就不再有效地根除细胞。鉴于 Fas 的常见表达，以及通常无法消除某些表达 Fas 的细胞，我们怀疑 Fas 受到严格控制。虽然 Fas 激活是临床上有益的化疗介质，但无意的 Fas 信号传导可能会导致肝损伤和死亡永久化。在这个项目中，我们寻找潜在的 Fas 结合调节因子，并鉴定了一种肿瘤抑制蛋白早幼粒细胞白血病蛋白 (PML)，它与增强细胞凋亡相关。我们选择测试显性失活 PMLRARa 因为它的表型更容易可视化。我们发现 PMLRARa（和 PML）与 Fas 结合并有效阻止细胞凋亡。当在小鼠肝脏中表达时，PMLRARa 可有效保护小鼠免受致死剂量的激动性抗 Fas 抗体诱导的死亡。 PML 的 B-box 结构域是与 Fas 结合所必需的，表明 PML 和 PMLRARa 使用该位点结合 Fas。 PML 和 PMLRARa 对转化生长因子 2 受体 (TGF2R) 调节的相反作用模型已经建立，我们怀疑 Fas 在类似的模型中发挥作用。我们的假设是 PML 积极调节 Fas 信号传导，这在死亡和增殖决策中发挥着关键作用。我们将使用 PML 显性失活突变体 PMLRARa 作为探针来表征对 Fas 的阻断作用。我们预计PML将表达具有Fas促进作用，并解释PML广为人知的细胞凋亡增强作用。我们的假设是 PML 是 Fas 的结合调节剂，并且可以调节这种相互作用以保护肝组织功能。该项目的长期目标是了解肝细胞的凋亡调节，以逆转 Fas 受体驱动的肝脏病理。