NEUROTROPHIN CONTROL OF TRIGEMINAL AXON DEVELOPMENT

神经营养因子对三叉神经轴突发育的控制

• 批准号: 6868891
• 负责人: MARK F JACQUIN
• 金额: $ 5.81万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6868891
• 关键词: axon; cell cell interaction; developmental neurobiology; embryo /fetus tissue /cell culture; genetically modified animals; immunocytochemistry; laboratory mouse; mixed tissue /cell culture; neurogenesis; neurotrophic factors; trigeminal nerve

Prior studies have revealed the trophic actions of neurotrophins in sensory neuron development. Proposed studies will address the trophic actions of neurotrophins in trigeminal (V) primary afferent development. Our working hypothesis is that neurotrophins regulatory sensory axon growth rate and mode during a critical period in development. Preliminary studies in expand co-cultures of the rat V periphery and brainstem show that NGF and NTF3 influence over axon elongation and brainstem arbor formation, respectively. Moreover, co-cultured V axons develop synaptic interactions with V brainstem cells that are similar to those seen in vivo. These data prompt the following 3 hypotheses; 1. Ion co-cultures of the V periphery and brainstem from embryonic mice, NGF produces axon elongation and NT3 produces axon arborization. TO test this, we will grow embryonic V explant co-cultures and wholemounts in the presence of exogenously added NGF or NT3. Axon growth rates in arborization responses will be quantified under these conditions. Immunohistochemical markers will be used to determine whether NGF and NT3 affect growth of all or specific V ganglion cell axons. Axon growth patterns will also be studied in dissociated trigeminal cell cultures under conditions of NGF or NT3 augmentation (or appropriate blocking agents). Explant co-cultures will also be used to assess whether NGF and NT3 promote synaptic interactions between V primary afferent and brainstem neurons. 2.In transgenic mice that over-express NGF or NT3 in the brainstem under a controllable promoter, V ganglion cells will develop aberrant axon elongation and arborization properties, respectively. Conversely, transgenic mice that over-express NGF or NT3 in the mysacial whiskerpad will develop normal axon morphologies in the brain stem. To test this, transgenic mice will be generated with controlled over- expression of NGF or NT3 in the brainstem or whiskerpad, by this, transgenic mice will be generated with controlled over-expression of NGF or NT3 in the brainstem or whiskerpad, by using the tetracycline- regulated gene system in CORE B. In the presence of tetracycline administered by diet or injection, NGF or NT3 will be over-expressed in particular target tissues during specified times in development. The morphology of identified V primary afferents will be revealed by intra- axonal recording and staining in these transgenic mice in adulthood. Axonal growth patterns will be quantified in CORE C. 3. Topographic aggregation patterns of brainstem cell (barrelettes) will be absent in transgenic mice that display aberrant primary afferent elongation and arborization properties induced by controlled over- expression of NGF or NT3 in the brainstem. Such patterning abnormalities will be transmitted to the thalamic barreloids and cortical barrels. To test this, above-described NGF or NT3 over-expressing mice that display altered primary afferent structure in the brainstem will be histochemically processed to reveal potential patterning alterations in the brainstem, thalamus and cerebral cortex. Image analysis of whisker- related patterns will be carried out in CORE C.

先前的研究揭示了神经营养蛋白在感觉神经元发育中的营养作用。拟议的研究将解决神经营养蛋白在三叉神经（V）主要传入发育中的营养作用。我们的工作假设是神经营养蛋白调节感官轴突的生长速率和模式在发育的关键时期。大鼠v外围和脑干的扩展共培养中的初步研究表明，NGF和NTF3分别对轴突伸长和脑干轴形成影响。此外，共培养的V轴突与Vivo中看到的V脑细胞形成突触相互作用。这些数据促使以下3个假设； 1。来自胚胎小鼠的V周围和脑干的离子共培养，NGF产生轴突伸长，而NT3产生轴突植物。为了测试这一点，我们将在存在外源添加的NGF或NT3的情况下种植胚胎v epplant共培养和全林。在这些条件下，将量化树木化反应中的轴突生长速率。免疫组织化学标记将用于确定NGF和NT3是否影响所有或特定V神经节细胞轴突的生长。在NGF或NT3增强（或适当的阻断剂）的条件下，还将在解离的三叉神经细胞培养物中研究轴突生长模式。外植物共培养还将用于评估NGF和NT3是否促进V主要传入和脑干神经元之间的突触相互作用。 2.在可控启动子下脑干中过表达NGF或NT3的转基因小鼠，V神经节细胞将分别发展出异常的轴突伸长和树皮化特性。相反，毛晶晶片中过表达NGF或NT3的转基因小鼠会在脑干中发展正常的轴突形态。为了测试这一点，将通过这种转基因小鼠在脑干或晶状体中的NGF或NT3过度表达而产生，通过这种情况，将通过使用Tetrycline-Conced condecter coce ing ing contiment core ng ing ing ing of tettry consection或whiskerpad中的NGF或nt3在脑干或晶格中受到Tetrection-contery contery contery contection contection或ngf ing ing ing ing consection ng consection ng consection或whiskerpad中的ngf或nt3的过表达。在开发的指定时间期间，将在特定目标组织中过表达。在成年期这些转基因小鼠中，轴突内记录和染色将揭示已识别的V主要传入的形态。轴突生长模式将在核心C中进行量化。在转基因小鼠中，将不存在脑干细胞（桶形）的地形聚集模式，这些小鼠将不存在由脑干中NGF或NT3的过度表达引起的异常原发性传入伸长和抗僵化特性。这种图案异常将传播到丘脑枪管和皮质桶。为了测试这一点，将在组织化学上处理上面描述的NGF或NT3过表达的小鼠，这些小鼠将在脑干中进行改变，以揭示脑干，丘脑和大脑皮层的潜在图案改变。晶须相关模式的图像分析将在CoreC中进行。