ADF/cofilin-actin rods in neurodegenerative diseases

在几乎所有培养的海马神经元的突起内，短暂的ATP耗竭迅速诱导杆状- 主要由肌动蛋白和ADF/Cofilin(AC)组成的形状结构。杆状结构，它隔离了 肌动蛋白的一部分，但几乎所有的AC，对应激神经元是暂时有益的，因为它 避免与肌动蛋白周转相关的ATP。然而，杆状突起可以完全阻断轴突，从而阻断。 运输并导致远端轴突枯萎。视杆细胞是阿尔茨海默病(AD)脑的显著特征 但不是缺乏淀粉样斑块的对照人脑。在动物的大脑中也发现了类似的结构 尼曼-匹克病(NPC1)和表达突变人的转基因小鼠(Tg2576) 淀粉样前体蛋白(APP)。在培养的神经元和小鼠脑片中，杆是由缺血诱导的， 过氧化氢、一氧化氮和兴奋性毒性谷氨酸。在高达20%的海马神经元中，无论是来自CA1区还是 CA，AD淀粉样β蛋白(Ab)也能诱导杆状突起：诱导呈剂量依赖性，发生在6小时内 治疗后及12~24小时后进入平台期。仅10 NM的抗体齐聚物就能产生显著的效果 与搅拌肽对照相比。仅有一部分神经元对抗体敏感的性质 将会被探索。视杆细胞阻断APP的囊泡运输。含APP的囊泡在末端堆积 和棒子的侧面。在这些停滞的小泡中有β-分泌酶裂解的APP，这表明这些小泡可能 是抗体产生和/或转化为更具破坏性的异构体的部位。综合来看，这些结果 建议一种AD模型，在该模型中，神经性应激，包括家族性AD形成的抗体，诱导杆停滞 囊泡运输和增加毒性抗体，从而在邻近细胞中诱导杆状。这样的模型可以解释 淀粉样斑块的形成，它会在损伤的初始部位周围扩大。使用细胞培养和 器官类型的脑片，我们将确定：1)视杆形成需要哪些粘连蛋白的活性；2)如果 可以确定AC中的突变可以防止杆状结构的形成；3)如果杆状结构促进生产或 抗体的寡聚化；4)是什么使神经元的子集对抗体敏感：以及5)脑的器质性 切片可以用作研究视杆在哪里形成以及它们如何破坏突触的模型。与以下内容相关 公共健康：广告极大地影响了美国老年人的生活质量，影响了25%的老年人。这 该提案测试了AD进展的新假说，并确定了可能的靶向干预地点。

Within neurites of nearly all cultured hippocampal neurons, transient ATP depletion rapidly inducesrod- shaped structures composed primarily of actin and ADF/cofilin (AC). Rod formation, which sequesters a portion of the actin but virtually all of the AC, is transiently beneficial to the stressed neuron because it spares ATP associated with actin turnover. However, rods can completely occlude the neurite, blocking transport and causing distal neurite withering. Rods are prominent features of Alzeimer's disease (AD) brain but not of control human brain lacking amyloid plaques. Similar structures are found in brains of animals with Niemann-Pick disease typed (NPC1) and of transgenic mice (Tg2576) expressing mutant human amyloid precursor protein (APP). In cultured neurons and mouse brain slices, rods are induced by ischemia, peroxide, NO, and excitotoxic glutamate. In up to 20% of hippocampal neurons, whether from region CA1 or CAS, the AD amyloid beta peptide (Ab) also induces rods: induction is dose-dependent, occuring within 6 h after treatment and plateauing 12-24 h later. As little as 10 nM of Ab oligomer has a significant effect compared to the scrambled peptide control. The nature of the sensitivity of only a subset of neurons to Ab will be explored. Rods block vesicular transport of APP. APP-containing vesicles accumulate at the ends and sides of rods. Within these stalled vesicles is beta-secretase cleaved APP, suggesting that these may be sites of Ab production and/or conversion into more damaging conformers. Taken together, these results suggest a model for AD in which neuronal stress, including Ab formed in familial AD, induces rods that stall vesicle transport and increase toxic Ab, thus inducing rods in neighboring cells. Such a model could explain the formation of amyloid plaques, which would enlarge around the initial site of injury. Using cell culture and organotypic brain slices, we will determine: 1) what activities of cofilin are required for rod formation; 2) if mutations in AC can be identified that prevent rod formation; 3) if rods promote the production or oligomerization of Ab; 4) what makes a subset of neurons sensitive to Ab: and 5) how organotypic brain slices can be used as a model to study where rods form and how they disrupt synapses. Relevance to public health: AD dramatically impacts life quality of senior Americans, affecting 25% of those > 85. This proposal tests a new hypothesis for AD progression and identifies possible sites for targeted intervention.