REGULATION OF TARGET-DEPENDENT NEURONAL DEATH

靶标依赖性神经元死亡的调节

• 批准号: 2270166
• 负责人: JAMES M SOHA
• 金额: $ 12.83万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1995-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2270166
• 关键词: afferent nerve; autoradiography; biomarker; cell cycle; cell death; cell growth regulation; cerebellar Purkinje cell; cerebellum; developmental neurobiology; electron microscopy; fluorescent dye /probe; granule cell; histology; laboratory mouse; mutant; neurogenesis; newborn animals; tissue mosaicism; tritium

The goal of this project is to better understand the process of naturally occurring neuronal death that plays a widespread role in normal mammalian development. The trophic interaction between afferent and target neuronal populations is relevant not only to human developmental disorders, but may also be an important element in degenerative diseases of aging. The model system selected for the proposed research is the granule cell-Purkinje cell circuit in the mouse cerebellum. There are two specific aims. The first is to determine when the period of target dependence actually commences, and how much cell death normally occurs while granule cell proliferation is still underway. Both the magnitude and timing of granule cell death will be accurately determined in normal animals, and in staggerer mutants that lack competent target from the outset. To do this, cohorts of granule cells having selected birthdates will be labeled in groups of mice by 3H-thymidine uptake and the fraction of labeled cells remaining will be assessed by autoradiography at subsequent times. A related issue concerns whether granule cells must reach a certain developmental threshold as measured by axon outgrowth before they become vulnerable to cell death. This question will be addressed by comparing the distribution of parallel fiber lengths in normal mice with that in target deficient mutants (lurcher and staggerer), using focal implants of the lipophilic fluorescent dye DiI in fixed cerebella. The second aim is to explore a hypothesis involving developmental deafferentation in lurcher<->wild type mouse chimeras. The hypothesis holds that an altered trophic environment is induced by the early death of mutant Purkinje cells and the subsequent deafferentation of their wild type counterparts, and that the altered environment is able to rescue a fraction of granule cells from cell death. This is interesting for two reasons: it suggests a feedback relationship during development, nd it suggests a role for these chimeras in identifying the trophic molecule. Lurcher chimeras will be constructed that incorporate an existing transgenic mouse line containing a Purkinje cell specific histochemical marker. These chimeras will extend our understanding of the aberrant Purkinje cell morphologies that characterize these mice and are key to the hypothesis. Also, a developmental electron microscopic study will determine whether the onset of these morphologies is consistent with the deafferentation hypothesis.

该项目的目的是更好地了解自然的过程 发生神经元死亡，在正常哺乳动物中起着广泛的作用 发展。 传入与目标之间的营养相互作用 神经元种群不仅与人类发展有关 疾病，但也可能是退行性疾病的重要因素 衰老。 为拟议研究选择的模型系统是 小脑小脑中的颗粒细胞 - 纯细胞电路。 有 两个具体的目标。 首先是确定目标时间何时 依赖实际上开始，通常发生多少细胞死亡 而颗粒细胞增殖仍在进行中。 两个大小 颗粒细胞死亡的时机将在正常情况下准确确定 动物，以及在缺乏胜任目标的较错的突变体中 一开始。 为此，颗粒细胞的同类颗粒细胞已经选择了生日 将通过3H-胸苷的摄取和分数将小鼠组标记 剩余标记的细胞将通过放射自显影评估 随后的时间。 一个相关的问题涉及颗粒细胞是否必须 达到一定的发育阈值，如轴突的生长 在它们变得容易受到细胞死亡之前。 这个问题将是 通过比较平行纤维长度的分布来解决 正常小鼠在目标不足突变体中（Lurcher和 使用亲脂性荧光染料DII的焦点植入物） 在固定小脑中。 第二个目的是探索涉及的假设 野生型小鼠嵌合体中的发育脱落。 这 假设认为，改变的营养环境是由 突变浦肯野细胞的早期死亡和随后的脱落 他们的野生型对应物，并且改变的环境能够 从细胞死亡中挽救一小部分颗粒细胞。 这是 有趣的是有两个原因：它暗示了在 开发，它建议这些嵌合体在识别 营养分子。 将构建Lurcher Chimeras 现有的转基因小鼠系，包含特定于Purkinje细胞的特异性 组织化学标记。 这些嵌合体将扩展我们对 这些小鼠和 是假设的关键。 另外，发育电子显微镜 研究将确定这些形态的发作是否是 与剥离假设一致。