Nuclear Rigidity Scales with Tissue Elasticity and Directs Cell Fate

该奖项的研究目的是阐明组织细胞中细胞核的机械和生化特性与不同组织的机械微环境之间的潜在关系。例如，脑组织是柔软的，而骨骼要硬得多，这就提出了一个问题，即组织之间的力学差异是否反映在这些组织中细胞核之间的力学差异上。单细胞机械工具、现代生化表征工具和统计力学工具的组合将通过分离的细胞核应用于一系列人类和小鼠组织。细胞核限制、保护和调节着成年人体内大约200种不同细胞类型的基因组。细胞核还拥有一组被称为层蛋白的结构蛋白，它可能具有关键的机械生物学作用，但生化分析将扩展到更完整的核蛋白集合。将使用荧光耦合微抽吸方法研究给定成分水平变化的培养细胞，以确定对机械性能的影响，而干细胞培养最终将提供对分化过程影响的见解。与此同时，核组装将通过为简单细胞（如红细胞）开发的粗粒度统计力学方法，以越来越高的分子细节水平进行模拟。这些研究可以显著增加该领域对与谱系依赖基因表达（即分化）相关的组织和核力学的理解，并可能有益于发育物理学和再生医学等领域。教育计划侧重于从软物质角度开发干细胞和蛋白质组学课程。当地高中科学教师将协助进行核隔离以及纳米和微观力学表征，目的是传播，而通过本科生研究经验的推广将有助于鼓励学生追求更高的学位。

The research objective of this award is to elucidate a potential relationship between the mechanical and biochemical properties of the nucleus in a tissue cell to the mechanical microenvironment of different tissues. For example, brain tissue is soft while bone is far stiffer, raising the question as to whether mechanical differences between tissues are reflected in mechanical differences between nuclei in these tissues. A combination of single cell mechanical tools, modern biochemical characterization tools, and statistical mechanics tools will be developed in application to a range of human and mouse tissues thru isolated nuclei. The nucleus confines, protects, and regulates the genome that is common to the roughly 200 different cell types in the adult. The nucleus also possesses an assembly of structural proteins called lamins that are likely to have a key mechanobiological role, but biochemical analyses will extend to a more complete set of nuclear proteins. Cultured cells in which the level of a given component is varied will be studied with fluorescence-coupled micro-aspiration methods to determine the impact on mechanical properties, and stem cell cultures will ultimately provide insight into the impact on differentiation processes. In parallel, nuclear assemblies will be simulated with an increasing level of molecular detail by coarse-grained statistical mechanical methods developed for simple cells such as red blood cells.These studies could add significantly to the field's understanding of tissue and nuclear mechanics in relation to lineage-dependent gene expression, i.e. differentiation, and they could benefit developmental physics, and regenerative medicine among other fields. The educational plan focuses on development of a course on stem cells and proteomics from a soft matter perspective. Local high school science teachers will assist in nuclear isolations as well as nano- and micro- mechanical characterizations, with the aim of dissemination, while outreach through research experiences for undergraduates will help to encourage students to pursue higher degrees.