Mechanisms and functions of p75 neurotrophin receptor signaling in astrocytes

星形胶质细胞中 p75 神经营养蛋白受体信号传导的机制和功能

基本信息

批准号：
8518998
负责人：
Katerina Akassoglou
金额：
$ 2.5万
依托单位：
J. DAVID GLADSTONE INSTITUTES
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-04-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8518998
关键词：
Astrocytes Atomic Force Microscopy Attenuated Binding Biochemical Biological Cell Differentiation process Cell Nucleus Cells Cicatrix Cleaved cell Coupling Data Deposition Development Dipeptides Disease Experimental Designs Extracellular Matrix Fibrin Generations Genes Genetic Transcription Glycine Goals Grant Injury Intervention Maps Mediating Modeling Molecular Multiple Sclerosis Mus NGFR Protein Natural regeneration Nerve Growth Factor Receptors Nervous system structure Neuraxis Nuclear Import Nuclear Pore Nuclear Pore Complex Nuclear Pore Complex Proteins Nuclear Translocation Pathogenesis Pathology Pathway interactions Phenylalanine Process Proteolysis Protocols documentation Receptor Signaling Regulation Reporter Research Role Signal Pathway Signal Transduction Spinal Cord Stroke Testing Transgenic Mice Transgenic Model Work chromatin immunoprecipitation design electron tomography in vitro Assay in vivo inhibitor/antagonist nervous system disorder novel nucleocytoplasmic transport overexpression presenilin public health relevance repaired research study secretase therapeutic development tissue repair

项目摘要

DESCRIPTION (provided by applicant): In central nervous system pathologies, including multiple sclerosis, stroke, spinal cord and traumatic injuries, scar formation consisting of reactive astrocytes and deposition of extracellular matrix is a major inhibitor of tissue repair. The molecular mechanisms that trigger astrocyte activation in nervous system disease remain incompletely characterized. We have shown that the neurotrophin receptor p75NTR regulates repair processes by inhibiting fibrin degradation and regulating cell differentiation. Our long-term goal is to characterize the molecular pathways that are responsible for the effects of p75NTR in nervous system pathogenesis, as a prerequisite for the development of therapeutic protocols that can specifically target p75NTR signaling and attenuate neuropathological disease processes. Our major hypothesis is that intramembrane proteolysis of p75NTR regulates TGF-¿ signaling to control astrocyte functions during development and disease. Our preliminary data demonstrate that a) the intracellular domain of p75NTR (p75ICD) is a novel component of the nuclear pore complex in astrocytes, b) p75NTR directly binds to the natively unfolded FG-domain of nucleoporin 153 (Nup153), c) TGF-¿ induces 3-secretase-dependant cleavage of p75NTR resulting in its translocation inside the nuclear pore, d) p75NTR regulates of Smad2, and e) p75NTR regulates astrocyte differentiation and TGF-¿ functions in the CNS in vivo. Our specific aims are designed to test our working model, in which intramembrane cleavage of p75NTR results in remodeling of the nuclear pore complex that allows nucleocytoplasmic shuttling of Smad2 and induces astrocyte differentiation and activation. We employ a multiphaceted experimental design that includes transgenic models of TGF¿-induced astrocyte activation, generation of new transgenic mice for cell-fate mapping of p75NTR - expressing cells, atomic force microscopy and three-dimensional electron tomography to determine the role of cleaved p75NTR in the dynamic remodeling of the nuclear pore complex in astrocytes, and biochemical experiments to define how p75NTR cleavage regulates Smad2 nucleocytoplasmic shuttling and its coupling to the TGF¿ transcriptional machinery. Identifying the molecular interplay between p75NTR and TGF¿ signaling pathways could potentially provide injury-specific targets for pharmacological intervention in a variety of diseases characterized by astrocyte scar formation and decreased capacity for tissue repair. PUBLIC HEALTH RELEVANCE: The astrocyte scar is a major inhibitor for regeneration in the CNS. Study of the molecular interplay between p75NTR and TGF¿ signaling pathways as a novel mechanism that regulates astrocyte activation could potentially provide injury-specific targets for pharmacological intervention in a variety of diseases characterized by astrocyte scar formation and decreased capacity for tissue repair.

描述（由适用提供）：在中枢神经系统病理中，包括多发性硬化症，中风，脊髓和创伤性损伤，由反应性星形胶质细胞组成的疤痕形成以及细胞外基质的沉积是组织修复的主要抑制剂。神经系统疾病中引发星形胶质激活的分子机制仍然没有完全表征。我们已经表明，神经营养蛋白受体P75NTR通过抑制纤维蛋白降解和调节细胞分化来调节修复过程。我们的长期目标是表征负责p75NTR在神经系统发病机理中影响的分子途径，这是可以专门针对p75NTR信号传导并衰减神经病理学疾病过程的治疗方案开发的先决条件。我们的主要假设是，p75NTR的膜内蛋白水解调节TGF-€信号传导以控制发育和疾病期间的星形胶质细胞功能。我们的初步数据表明，a）p75ntr（p75ICD）的细胞内结构域是星形胶质细胞中核孔复合物的新成分核孔内的易位，d）p75ntr调节了Smad2的调节和e）p75ntr调节体内中枢神经系统中星形胶质细胞分化和TGF-€的功能。我们的具体目的旨在测试我们的工作模型，其中p75NTR的膜内切割会导致核孔复合物的重塑，从而允许核孔隙smad2的核孔隙并诱导星形胶质细胞分化和激活。我们采用了多核实验设计，其中包括TGFTO诱导的星形胶质细胞激活的转基因模型，新的转基因小鼠的生成用于p75ntr-表达细胞的细胞命令图，原子力显微镜和三维电子层析成像，以确定裂解的P75NTR在动态重塑中的作用，以确定核孔的作用。定义P75NTR裂解如何调节SMAD2核囊质穿梭及其与TGF转录机械的耦合。识别p75NTR和TGF¿信号通路之间的分子相互作用，可以潜在地提供特定损伤的靶标，以针对各种以星形胶质细胞疤痕形成和改善组织修复能力为特征的各种疾病中的药物干预。公共卫生相关性：星形胶质细胞疤痕是CNS再生的主要抑制剂。研究p75NTR和TGF¿信号通路之间的分子相互作用是调节星形胶质细胞激活的一种新型机制，可以潜在地提供特异性的损伤靶标，以用于药物干预的损伤，以各种疾病为特征，这些疾病具有星形胶质疤痕形成和改善组织修复的能力。