Nucleoskeleton-Cytoskeleton Connections and Cell Polarity in Aging

衰老过程中的核骨架-细胞骨架连接和细胞极性

• 批准号: 10619511
• 负责人: Gregg G Gundersen
• 金额: $ 41.65万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10619511
• 关键词: Acceleration; Actins; Actomyosin; Address; Adhesions; Age; Aging; Cell Aging; Cell Nucleus; Cell Polarity; Cell physiology; Cell secretion; Cells; Cellular Morphology; Centrosome; Child; Complex; Cytoplasm; Cytoskeletal Proteins; Cytoskeleton; Data; Defect; Dermis; Disease; Dynein ATPase; Fibroblasts; Filament; Functional disorder; Genes; Human; Impaired wound healing; Individual; Lead; Mass Spectrum Analysis; Mediating; Mendelian disorder; Methods; Microfilaments; Microtubules; Molecular; Movement; Mus; Nuclear; Nuclear Envelope; Nuclear Inner Membrane; Nuclear Lamina; Nuclear Outer Membrane; Physiological; Play; Process; Progeria; Protein Isoforms; Protein Secretion; Proteins; RNA Splicing; Role; Skin; Skin wound healing; Splice-Site Mutation; Syndrome; System; Testing; Transgenic Mice; Variant; age related; aged; autocrine; cell age; healing; human subject; in vivo; insight; lamin C; migration; normal aging; novel; overexpression; paracrine; prelamin A; protein purification; reconstitution; release factor; skin wound; tissue culture; wound; wound healing

Project Summary The cytoskeleton and its connections to the nucleus play fundamental roles in establishing cellular morphology, polarity, migration and adhesion. Because of their essential roles in these cellular functions, it is critically important to understand the changes that take place in cytoskeletal systems and their nuclear connections during the normal process of cellular aging. Despite this importance, remarkably little is known about the role of the cytoskeleton in physiologically aging. Our preliminary studies have led to the discovery of a fundamental cell polarity defect that occurs in fibroblasts from children with the accelerated aging disorder Hutchinson- Gilford progeria syndrome and also in fibroblasts from physiologically-aged individuals. This defect results from unbalanced 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/nesprin proteins. In aging, there is a preferential increased interaction of nesprin-2G with microtubules (supported by SUN1) versus actin microfilaments (supported by SUN2). This has led to our overall hypothesis that altered nucleocytoskeletal connections mediated by the LINC complex causes an intrinsic cell polarity defect in physiological aging as well as an accelerated aging disorder. We further hypothesize that this defect is at least in part mediated by a protein factor secreted by cells from aged individuals. We propose to test these hypotheses in three specific aims. In Aim 1, we will decipher the mechanism underlying the cell polarity defect in physiological aging. We will determine how increased SUN1 levels are established in the nuclear envelope during aging, explore how SUN1 interaction with nesprin-2G biases its interaction toward microtubules and examine how cytoplasmic microtubules are impacted by their excessive interaction with the nuclear envelope. In Aim 2, we will examine the role of the age-dependent cell polarity defect in would healing in vivo. We will examine cutaneous wounds from young and old mice to determine if the same mechanisms that generate polarity defects in tissue culture are operative in vivo as well as examine wound healing and fibroblast polarity in transgenic mice overexpressing SUN1 in fibroblasts. In Aim 3, we will purify and characterize a soluble factor secreted from aged cells that leads to defective cell polarity. We will use complementary methods of mass spectrometry and protein purification to identify this factor we call FRAC, for Factor Released from Aged Cells. Completion of these aims will lead to novel insights into how alterations in nucleocytoskeltal connections at the LINC complex lead to a fundamental cell polarity defect in aging.

项目摘要 细胞骨架及其与细胞核的连接在建立细胞形态方面起着基础性的作用， 极性、迁移性和粘附性。由于它们在这些细胞功能中的基本作用，它是至关重要的 了解细胞骨架系统及其核连接发生的变化很重要 在细胞衰老的正常过程中。尽管这一点很重要，但令人惊讶的是，人们对这些因素的作用知之甚少。 生理性衰老中的细胞骨架。我们的初步研究发现了一种基本的 Hutchinson加速衰老障碍儿童成纤维细胞中出现的细胞极性缺陷 吉尔福德早衰症和生理年龄个体的成纤维细胞中也有。这一缺陷是由 内核膜内侧的核膜和核膜之间的不平衡连接 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 由内核组成的核骨架和细胞骨架复合体(LINC)的连接物介导 膜太阳蛋白和外核膜Kash/Nesprin蛋白。在老龄化方面，有一种优惠 Nesprin-2G与微管(由SUN1支持)与肌动蛋白微丝的相互作用增强 (SUN2支持)。这导致了我们的总体假设，即改变了核细胞骨架连接 由LINC复合体介导的在生理衰老中导致固有的细胞极性缺陷以及 加速衰老障碍。我们进一步假设，这种缺陷至少部分是由一种蛋白质介导的。 老年人细胞分泌的因子。我们建议在三个具体目标上检验这些假设。在……里面 目的1，我们将破译生理衰老过程中细胞极性缺陷的机制。我们会 确定在衰老过程中如何在核膜中建立升高的SUN1水平，探索如何 SUN1与Nesprin-2G的相互作用使其相互作用偏向微管，并研究细胞质如何 微管受到与核膜过度相互作用的影响。在目标2中，我们将研究 依赖年龄的细胞极性缺陷在体内修复过程中的作用。我们会检查皮肤伤口 以确定在组织培养中产生极性缺陷的相同机制 在体内运行，并在转基因小鼠中检查伤口愈合和成纤维细胞极性 在成纤维细胞中过表达SUN1。在目标3中，我们将纯化和鉴定一种由 老化的细胞，导致细胞极性有缺陷。我们将使用互补的质谱学方法和 蛋白质纯化以鉴定这种因子，我们称之为FRAC，即从衰老细胞中释放的因子。完成 这些目标将导致对LINC复合体中核-胞质连接的改变如何产生新的见解 导致老化过程中基本的细胞极性缺陷。