PATHOLOGICAL MECHANISMS IN TRANSYNAPTIC CALCIUM OVERLOAD

描述(摘自申请者的摘要)：本研究的目标是 了解突触兴奋性毒性变性的过程 使用动物模型。人类神经退行性疾病的动物模型有 对探索细胞和生化介质和分子具有重要价值 缓慢发展的疾病过程的发病机制。慢速频道 先天性肌无力综合征(SCCMS)是由导致 大鼠脑乙酰胆碱受体(AM)离子通道延迟关闭 神经肌肉(NMJ)。延迟的通道关闭与钙离子有关 NMJ超负荷和变性、AChR丢失和进行性肌肉 软弱。因此，SCCMS是一种遗传性兴奋性中毒性障碍的原型。 利用转基因小鼠技术和AChR亚单位的定点突变 编码序列，我们开发了慢通道转基因小鼠 显示人类所有特征的SCCS动物模型 疾病。在该提案中，调查员建议：(1)确定是否 慢通道转基因小鼠神经肌肉的表达减少 突触特异性基因。这将通过比较信使核糖核酸水平来实现 对于AChR亚单位基因和其他NMJ特异基因在转基因和 对照小鼠以及变性的NMJ核和远离NMJ的核之间 细胞核；(2)确定细胞器损伤的原因(S)和终板 慢通道小鼠的肌病。细胞内损伤的三种可能途径： 钙激活的蛋白水解酶的激活，自由基的氧化损伤， 并将使用一种特定抗体探针的组合来探索细胞凋亡 和染色来寻找受损的蛋白质和DNA在NMJ和遗传和 对这些通路的药理操纵以改变血管紧张素转换酶 疾病；(3)。确定奎尼丁是否能保护慢通道 终板变性转基因小鼠。

DESCRIPTION (Adapted from applicant's abstract): The goal of this research is to understand the processes involved in excitotoxic degeneration of synapses using an animal model. Animal models for human neurodegenerative disease are of great value for exploring the cellular and biochemical mediators and molecular pathogenesis of a slowly progressive disease process. The slow channel congenital myasthenic syndrome (SCCMS) is caused by mutations that result in delayed closure of the ion channel of the acetylcholine receptor (AM) of the neuromuscular (NMJ). The delayed channel closure is associated with calcium overload and degeneration of the NMJ, AChR loss, and progressive muscle weakness. Thus, the SCCMS is a prototype for a hereditary excitotoxic disorder. Using transgenic mice technology and site-directed mutagenesis of AChR subunit coding sequences, we have developed the slow-channel transgenic mouse, an animal model for the SCCS that manifest all the features seen in the human disease. In this proposal, the investigator proposes to: (1) Determine whether slow-channel transgenic mice have reduced expression of neuromuscular synapse-specific genes. This will be accomplished by comparison of mRNA levels for the AChR subunit genes and other NMJ-specific genes between transgenic and control mice and between degenerating NMJ nuclei and remote from the NMJ nuclei; (2) Determine the cause(s) of the organellar damage and endplate myopathy in slow-channel mice. Three likely pathways of intracellular damage: activation of calcium-activated proteases, oxidative damage by free radicals, and apoptosis will be explored using a combination of specific antibody probes and stains to look for damaged proteins and DNA at the NMJ and genetic and pharmacological manipulation of these pathways to alter the course of the disease; and (3). Determine if quinidine can protect the slow-channel transgenic mice from endplate degeneration.