Nucleoskeleton-Cytoskeleton Connections and Cell Polarity in Aging

摘要 细胞骨架及其与细胞核的连接在建立细胞的过程中起着至关重要的作用。 形态、极性、迁移和基材附着力。我们发现了一个基本的细胞极性缺陷 这发生在生理性衰老和患有加速衰老障碍的儿童中。 综合症。这一缺陷是由于内侧核板之间的连接不平衡造成的 内核膜和两个主要的细胞骨架蛋白系统：肌动蛋白/微丝和微管。 这些连接是由核骨架和细胞骨架(LINC)复合体组成的连接物介导的 内核膜SUN和外核膜KASH蛋白。在老龄化方面，有一种优惠 增加的SUN1与微管的相互作用与SUN2与肌动蛋白/微丝的相互作用。母公司资助的赠款 (R01 AG064944)用于本补充应用程序的目的是测试更改后的假设 LINC复合体介导的核骨架连接在衰老过程中会导致固有的细胞极性缺陷。在……里面 在这一补充中，我们将扩大父项目，以检查阿尔茨海默病患者的核细胞骨架连接 阿尔茨海默病(AD)和相关的神经退行性痴呆。神经元微管相关蛋白tau 在这些疾病的神经元和淀粉样β蛋白(Aβ)寡聚体中以过度磷酸化的形式积累 细胞外蓄积，诱导tau蛋白过度磷酸化。因此，我们将测试tau的假设 和寡聚体Aβ改变微管与LINC复合体的结合并干扰细胞的生成 成纤维细胞模型系统和初级神经元中的极性。在目标1中，我们将确定Tau和Aβ是否会影响 微管与LINC复合体的相互作用改变了细胞极性的产生。要做到这一点，我们将 使用资助父母奖中建议的健壮的成纤维细胞模型系统。在目标2中，我们将确定tau是否 A-β寡聚体诱导的过度磷酸化增加微管与核的相互作用 并进行实验以确定这些改变的相互作用是否是同时发生的病理变化的基础 初级神经元。最后，我们还将评估随着年龄增长而出现的SUN1过度表达对 初级神经元。本研究将提示Tau/Aβ诱导的LINC复合体功能障碍。 阿尔茨海默病和相关痴呆的发病机制，并有可能确定治疗发展的靶点 治疗。

SUMMARY The cytoskeleton and its connections to the nucleus play fundamental critical roles in establishing cellular morphology, polarity, migration and substrate adhesion. We have discovered a fundamental cell polarity defect that occurs in physiological aging and in children with the accelerated aging disorder Hutchinson-Gilford progeria syndrome. This defect results from imbalanced connections between the nuclear lamina on the inner aspect of the inner nuclear membrane and two major cytoskeletal protein systems: actin/microfilaments and microtubules. These connections are mediated by the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex composed of inner nuclear membrane SUN and outer nuclear membrane KASH proteins. In aging, there is a preferential interaction of increased SUN1 with microtubules versus SUN2 with actin/microfilaments. The parent funded grant (R01 AG064944) for this supplemental application is designed to test the hypothesis that altered nucleocytoskeletal connections mediated by the LINC complex cause an intrinsic cell polarity defect in aging. In this supplement, we will expand the parent project to examine nucleocytoskeletal connections in Alzheimer disease (AD) and related neurodegenerative dementias. The neuronal microtubule-associated protein tau accumulates in a hyperphosphorylated form in neurons in these disorders and amyloid-beta (Aβ) oligomers accumulate extracellularly and induce hyperphosphorylation of tau. We will therefore test the hypothesis that tau and oligomeric Aβ alter microtubule association with LINC complexes and interfere with the generation of cell polarity in a fibroblast model system and in primary neurons. In Aim 1, we will determine if tau and Aβ influence the interactions of microtubules with LINC complexes and alter the generation of cell polarity. To do so, we will use a robust fibroblast model system as proposed in the funded parent award. In Aim 2, we will determine if tau hyperphosphorylation induced by oligomeric Aβ oligomers increases microtubule interactions with the nucleus and perform experiments to establish if these altered interactions underlie concurrent pathological changes in primary neurons. Finally, we will also assess the effects of SUN1 overexpression, which occurs with aging, on primary neurons. This research will implicate tau/Aβ-induced dysfunction of the LINC complex in the pathogenesis of AD and related dementia, and potentially identify targets for the development of therapeutic treatments.