Nuclear Mechanics varies with Tissue Mechanics & Regulates Cytoskeleton

核力学随组织力学而变化

• 批准号: 8928873
• 负责人: Dennis E. Discher
• 金额: $ 23.33万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-14 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8928873
• 关键词: Acute; Adult; Affect; Age of Onset; Aging; Animals; Aspirate substance; Automobile Driving; Back; Biomechanics; Birth; Blood; Blood Cells; Brain; Cardiac Myocytes; Cardiology; Cell Line; Cell Nucleus; Cell Survival; Cells; Cessation of life; Chick Embryo; Cicatrix; Collagen; Congenital Heart Defects; Connective Tissue; Cysteine; Cytoskeletal Gene; Cytoskeleton; Data; Development; Dilated Cardiomyopathy; Disease; Elasticity; Embryo; Embryonic Heart; Erythrocytes; Exhibits; Extracellular Matrix; Feedback; Feeds; Gel; Gene Expression; Genes; Genetic Transcription; Goals; Hair; Heart; Human; In Situ; Infarction; Keratin; Knock-out; Knockout Mice; Label; Lamin Type A; Lamin Type B; Lamins; Lead; Life; Link; Liquid substance; Marrow; Mathematics; Measurement; Measures; Mechanical Stress; Mechanics; Methods; Molecular; Molecular Conformation; Monitor; Mus; Mutation; Myosin Type II; Nail plate; Nuclear; Nuclear Lamin; Nuclear Lamina; Nuclear Structure; Organ; Pathway interactions; Peptides; Phosphorylation; Progeria; Proteins; Pump; Regulation; Relative (related person); Reporter; Retinoids; Rheology; Role; Science; Shotguns; Solid; Stem cells; Stress; Structural Protein; Structure; System; Testing; Therapeutic; Time; Tissue Differentiation; Tissues; Transcript; Transfection; Ursidae Family; Work; base; blastomere structure; blebbistatin; bone; embryo tissue; heart cell; mimetics; novel; promoter; public health relevance; regenerative; response; sensor; soft tissue; stoichiometry

 DESCRIPTION (provided by applicant): Biomechanical aspects of embryonic tissues are poorly understood, especially nuclear mechanics. Very early embryos are well-known to be very soft and have very low levels of the nuclear structure protein lamin-A, which we have shown by single cell manipulations means that the nucleus is softer than in almost any adult cell [Swift Science 2013]. Initial differentiation to tissue turns on lamin-A transcription in heart, which seems important because knockout mice exhibit 'developmental defects of the heart' and die shortly after birth [Kubben Nucleus 2011], but lamin-A protein characterization is lacking in intac embryonic tissues as studied here. Lamin-A mutations cause a range of diseases with various ages of onset, including dilated cardiomyopathy (DCM) and accelerated aging (Progeria) affecting heart. Lamin-A is also known to affect differentiation and cell survival - all of which motivates studies to see & perturb the lamina in beating hearts. With adult tissue and primary cells, we have found that lamin-A levels are nearly proportional to tissue stiffness E [Swift Science 2013]. Relatively stiff connective tissues bear high mechanical stress, such as bone and even heart, and they have high lamin-A, suggesting stiff nuclei resist the stress. In contrast, very soft tissues such as brain and marrow that bear little stress express low lamin-A. B-type lamins are comparatively constant in the solid tissues, so that lamin-A:B stoichiometry seems a mechanosensor of stiffness and stress in adult tissues. We have worked through the mathematics of a simple mechanobiological gene circuit that fits findings for adult cells and tissues. Our hypothesis here is that Lamins in normal embryos adjust developmentally in response to mechanical stresses. Our goal is to determine and perturb mechano- regulation of lamin gene circuits in developing embryos, with a focus on what develops into a stiff heart relative to fluid blood. We focus on the facile chick embryo system per our recent studies that demonstrate acute sensitivity of beating heart to matrix elasticity [Majkut Curr Biol 2013]. Chick has advantages including the fact that chick erythrocytes have lamins, but we will at the end compare to developing mouse tissues. First we will quantify lamin protein levels throughout development by Mass Spec, and we will assess their stress and stiffness sensitivity with novel measurements and perturbations. We will relate embryonic lamina measurements to nuclear rheology and perturb the levels to validate relationships and molecular mechanisms. Preliminary data shows that beating chick hearts are easily transfected, so that Lamin Promoter- Reporter constructs can be tested as in situ mechanosensors of stress and stiffness. The lamina also enhances maturation and differentiation, and initial data with adult cells indicates feedback to cytoskeletal gene expression and the retinoid pathway of therapeutic relevance. Our studies should ultimately reveal the nuclear lamina as a multi-factorial, embryonic stress sensor that feeds back into broader structural regulation. 16

 描述（由适用提供）：胚胎组织的生物力学方面知之甚少，尤其是核力学。非常早期的胚胎众所周知，非常柔软，并且具有非常低的核结构蛋白lamin-A水平，我们通过单细胞操作表明，这意味着核us比几乎任何成人细胞都柔软[Swift Science 2013]。最初分化与组织的lamin-A突变会导致各种发作年龄的疾病，包括扩张的心肌病（DCM）和影响心脏的加速衰老（后代）。 lamin -a也众所周知会影响分化和细胞的生存 - 所有这些动机研究都可以看到和扰动层次。在成年组织和原代细胞的情况下，我们发现层粘连蛋白A的水平几乎与组织刚度E成正比[Swift Science 2013]。相对僵硬的连接正时正具有较高的机械应力，例如骨骼甚至心脏，并且具有高层固定层-A，表明刚性核能抵抗应力。相比之下， 非常软的组织，例如大脑和骨髓，具有很少的压力表达低层粘连蛋白-A。在固体组织中，B型层粘蛋白相对恒定，因此lamin-a：b化学计量似乎似乎是成年组织中刚度和应力的机械学。我们已经通过一个简单的机械基因回路的数学工作，该基因符合成人细胞和组织的发现。我们在这里的假设是，正常胚胎中的lamins响应机械应力而发育中调整。我们的目标是确定和扰动层粘连基因回路的机理调节，以开发胚胎，重点是相对于液体血液发展成僵硬的心脏。根据我们最近的研究表明，跳动心脏对基质弹性的急性敏感性[Majkut Curr Biol 2013]。雏鸡具有优势，包括雏鸡红细胞具有lamins的事实，但我们最终将与发展小鼠组织相比。首先，我们将通过质量规格来量化整个层蛋白蛋白水平，并通过新颖的测量和扰动来评估其应力和僵硬敏感性。我们将将胚胎层层测量与核流变学联系起来，并扰动验证关系和分子机制的水平。初步数据表明，跳动的雏鸡心脏很容易翻译，因此可以将层状启动子记者的构建体视为应力和刚度的原位机制。薄片还增强了成熟和分化，而成人细胞的初始数据表明对骨骼基因表达和类维生素性途径相关性的反馈。我们的研究最终应揭示核薄片是一种多因素的胚胎应力传感器，可以反馈到更广泛的结构调节中。 16