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: 8095442
• 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/8095442
• 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. PUBLIC HEALTH RELEVANCE: The Fas system is an important cell elimination system that has several established functions, including the elimination of autoreactive lymphocytes and infected and defective cells and cells damaged by chemotherapy and irradiation. We have identified promyelocytic leukemia protein as a binding and potential key regulator of Fas signaling. This project will characterize the binding with Fas and demonstrate how Fas is regulated in liver cells and in mice; thus by showing the site of regulation of Fas, we will be able to identify an effective therapeutic approach for liver disorders driven by Fas signaling.

描述(申请人提供)：这个项目建立在我们最近观察到的Fas死亡受体调控的基础上，将我们带到一个新的研究领域，即肝细胞分析，在这个领域，Fas在调节肝脏疾病方面发挥着关键作用。死亡受体在许多细胞死亡/增殖决定中起着关键作用。更具体地说，Fas死亡受体在肝组织中起着关键作用，决定了感染和毒素引起的细胞应激刺激的结果。Fas系统是一种重要的细胞清除系统，具有多种既定的功能，包括清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，如果没有Fas系统，在Fas-/-细胞中，许多临床化疗和电离辐射在根除细胞方面不再有效。考虑到Fas的普遍表达，通常无法消除一些表达Fas的细胞，我们怀疑Fas处于严格控制之下。虽然Fas的激活是临床上有益的化疗中介，但无意中的Fas信号可能会使肝脏损伤和死亡永久化。在这个项目中，我们寻找了潜在的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)，它与促进细胞凋亡有关。我们选择测试显性负性PMLRARa，因为它的表型更容易可视化。我们发现PMLRARa(和PML)与Fas结合，并有效地阻止细胞的凋亡。当在小鼠肝脏中表达时，PMLRARa有效地保护小鼠免受致死剂量的激动型抗Fas抗体诱导的死亡。PML的B-box结构域是与Fas结合所必需的，这表明PML和PMLRARa利用这个位点与Fas结合。已经建立了PML和PMLRARa对转化生长因子2受体(TGF2R)调节的相反作用模型，我们怀疑Fas的作用模式类似。我们的假设是，PML积极调节Fas信号，Fas信号在死亡和增殖决策中发挥关键作用。我们将以PML显性-负性突变体PMLRARa为探针，研究其对Fas的阻断作用。我们预计PML的表达将具有促进Fas的作用，并将解释众所周知的PML促进细胞凋亡的作用。我们的假设是，PML是Fas的结合调节因子，这种相互作用可以被调节以保护肝组织的功能。该项目的长期目标是了解Fas受体驱动的肝细胞凋亡调控，从而逆转肝脏病理。 与公共卫生相关：Fas系统是一种重要的细胞清除系统，具有多种既定功能，包括清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。我们已经确定早幼粒细胞白血病蛋白是Fas信号转导的一个结合的和潜在的关键调节因子。本项目将表征与Fas的结合，并展示Fas在肝细胞和小鼠中是如何调节的；因此，通过显示Fas的调节部位，我们将能够找到一种有效的治疗Fas信号驱动的肝脏疾病的方法。