Control of reactive astrocytes by Notch1 and Amyloid Precursor Protein

Notch1 和淀粉样前体蛋白对反应性星形胶质细胞的控制

• 批准号: 8515540
• 负责人: JEFFREY L SPEES
• 金额: $ 32.19万
• 依托单位: UNIVERSITY OF VERMONT & ST AGRIC COLLEGE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8515540
• 关键词: Amyloid beta-Protein Precursor; Anterior; Anti-Inflammatory Agents; Anti-inflammatory; Area; Aspartic Endopeptidases; Astrocytes; Biochemical; Blood - brain barrier anatomy; Brain; CD44 gene; Catalytic Domain; Cell Nucleus; Cells; Cicatrix; Cleaved cell; Complex; DNA-Binding Proteins; Data; Development; Embryo; Enhancers; ErbB4 gene; Genetic Transcription; Glial Fibrillary Acidic Protein; Immune Sera; Immunohistochemistry; Infarction; Inflammatory; Inflammatory Response; Injection of therapeutic agent; Injury; Intra-Arterial Infusions; Invaded; Knockout Mice; Lead; Mediation; Membrane; Membrane Proteins; Molecular; Morphology; Mus; Needles; Neural Crest; Neurons; Nuclear; PTPRC gene; Permeability; Pharyngeal structure; Phenotype; Process; Proliferating; Proteolysis; Recovery; Signal Transduction; Stem cells; Stroke; Testing; Therapeutic; Tissues; astrogliosis; axon regeneration; central nervous system injury; design; gamma secretase; gliogenesis; improved; in vivo; inhibitor/antagonist; nerve stem cell; neurogenesis; neuronal survival; nicastrin protein; notch protein; presenilin; presenilin-1; presenilin-2; protein expression; public health relevance; repaired; research study

DESCRIPTION (provided by applicant): Reactive astrogliosis and the subsequent formation of a glial scar are robust phenomena that occur following diverse CNS injuries. Surprisingly, the molecular signals that control the proliferation of reactive astrocytes or their functions in vivo are poorly understood. Defining the molecular control of reactive astrocyte proliferation and function may lead to therapeutic strategies that modify specific signals in reactive astrocytes to preserve tissue or improve recovery after CNS injury. We demonstrate that intra-arterial infusion of the gamma secretase (GS) inhibitor DBZ (Dibenzazepine) after stroke significantly reduced the proliferation of reactive astrocytes in the peri-infarct area of the cortex, significantly reduced the expression of glial fibrillary acidic protein (GFAP, a marker of activated hypertrophic astrocytes), and significantly increased stroke infarct volumes. The absence of reactive astrocytes after stroke and DBZ treatment correlated with a significant increase in the number of CD45-positive inflammatory cells that invaded the stroke penumbra. Similarly, stereotaxic injection of DBZ directly into the cortex reduced the numbers of proliferating reactive astrocytes surrounding the brain stab injury (needle track) compared with vehicle-injected controls. Reactive astrocytes surrounding the brain stab injury that remained after DBZ injection possessed an altered morphology with a significant reduction in average number of processes, number of branch points, and number of branch ends. Immunohistochemistry with antisera specific to GS cleavage products demonstrated nuclear localization of NICD1 (Notch1) and AICD in reactive astrocytes after cortical injury. DBZ blocks the catalytic activity of Presenilin 1, a component of GS. Experiments designed to specifically delete Notch1 and APP from reactive astrocytes prior to stroke using conditional knockout mice demonstrated that both regulate cortical reactive astrocytes in the peri-infarct area after stroke. Collectively our results indicate that Presenilin 1, Notch1, and APP regulate reactive astrocytes after stroke. Specific Aims: 1. To determine if Presenilin 1 acts as a global regulator of reactive astrogliosis after stroke. 2. To determine whether Notch1 or APP signaling controls the proliferation, morphology, and/or anti-inflammatory functions of reactive astrocytes after stroke. 3. To determine whether Presenilin 1, Notch1, or APP expression in reactive astrocytes is necessary for repair of the blood brain barrier after stroke.

描述（由申请人提供）：反应性星形胶质细胞增生和随后的胶质瘢痕形成是多种CNS损伤后发生的强烈现象。令人惊讶的是，控制反应性星形胶质细胞增殖或其在体内功能的分子信号知之甚少。定义反应性星形胶质细胞增殖和功能的分子控制可能会导致治疗策略，修改反应性星形胶质细胞中的特定信号，以保护组织或改善CNS损伤后的恢复。 我们证明，脑卒中后动脉内灌注γ分泌酶（GS）抑制剂DBZ（二苯并氮杂卓）可显著降低皮质梗死周围区域反应性星形胶质细胞的增殖，显著降低胶质细胞酸性蛋白（GFAP，活化肥大星形胶质细胞的标志物）的表达，并显著增加脑卒中梗死体积。脑卒中和DBZ治疗后反应性星形胶质细胞的缺乏与侵入脑卒中半暗带的CD 45阳性炎性细胞数量的显著增加相关。类似地，与注射溶剂的对照组相比，直接将DBZ立体定位注射到皮质中减少了脑刺伤（针迹）周围增殖反应性星形胶质细胞的数量。DBZ注射后脑刺伤周围的反应性星形胶质细胞具有改变的形态，平均突起数、分支点数和分支末端数显著减少。免疫组织化学与抗血清特异性GS裂解产物表明，NICD 1（Notch 1）和AICD在皮质损伤后反应性星形胶质细胞的核定位。DBZ阻断GS的组分早老素1的催化活性。实验设计专门删除Notch 1和APP从反应性星形胶质细胞中风前使用条件性敲除小鼠证明，都调节皮质反应性星形胶质细胞中风后梗死周围地区。总的来说，我们的研究结果表明，早老素1，Notch 1和APP调节中风后的反应性星形胶质细胞。具体目标：1。确定早老素1是否作为卒中后反应性星形胶质细胞增生的整体调节因子。2.确定Notch 1或APP信号是否控制卒中后反应性星形胶质细胞的增殖、形态和/或抗炎功能。3.确定反应性星形胶质细胞中的Presenilin 1、Notch 1或APP表达是否是卒中后血脑屏障修复所必需的。