RoL: FELS: EAGER Rules for cellular adaptation to the mechanical properties of their environment

动物体细胞，如成纤维细胞和内皮细胞，在软表面（底物）与硬底物上培养时，在增殖程度、细胞死亡、分化、细胞扩散和迁移方面表现出一致的功能差异。细胞外环境的机械特性也影响细胞内特征，包括细胞骨架组织、染色质压实和基因表达。该项目将使用实验技术来揭示真核体细胞（形成生物体身体的细胞）对其微环境的机械刚性的适应的进化规则，我们称之为机械进化。如果成功，这项研究将突出机械线索在细胞进化中的重要性，这将为细胞力学和进化细胞生物学领域带来新的方向。此外，该项目将促进对生物材料实验进化作为体细胞工程工具的认识。该项目将为化学工程专业的本科生、高中生和一名女研究生提供培训机会。该项目希望发现两个基本规律。规则1：表型可塑性。以前适应刚性粘附底物的小鼠成纤维细胞的复制种群将被允许在不同刚性的底物上进化。重复的细胞群将被培养并在严格控制刚性的基质上连续传代2年（~360-500代，传代N~1000个细胞）。如果以及如何衬底机械性能一致地选择一套细胞特征特征在不同水平的生物组织将被调查。规则2：突变输入。重复群体将保持如上所述，除非群体规模很小（传代时N~5个细胞）；这些群体被称为“突变积累”（MA）系。通过比较小N和大N下的进化，可以推断出对底物刚性的适应以及表型可塑性的进化在多大程度上受到突变输入的约束，而在多大程度上受到相关性状的相反选择的约束。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Animal somatic cells such as fibroblasts and endothelial cells display consistent functional differences when cultured on soft surfaces (substrates) compared to stiff substrates in the degree of proliferation, cell death, differentiation, cell spreading and migration. Mechanical properties of the extracellular environment also affect intracellular features including cytoskeletal organization, chromatin compaction, and gene expression. This project will use experimental techniques to uncover evolutionary rules underlying the adaptation of eukaryotic somatic cells (cells forming the body of the organism) to the mechanical rigidity of their microenvironment, what we call mechano-evolution. If successful, this research will highlight the importance of mechanical cues in cellular evolution, which can give rise to new directions in the fields of cell mechanics and evolutionary cell biology. Also, this project will promote an appreciation for experimental evolution on biomaterials as a tool to engineer somatic cells. The project will provide training opportunities to undergraduates, high school students and a female graduate student in chemical engineering.The project hopes to discover two fundamental rules. Rule 1: Phenotypic plasticity. Replicate populations of mouse fibroblasts previously adapted to a rigid adhesive substrate will be allowed to evolve on substrates of different rigidities. Replicate populations of cells will be cultured and passed continuously on substrates of carefully controlled rigidity for two years (~360-500 generations, N~1000 cells at passage). If and how substrate mechanical properties consistently select for a suite of cellular traits features at different levels of biological organization will be investigated. Rule 2: Mutational input. Replicate populations will be maintained as above, except at very small population size (N~5 cells at passage); these populations are called "mutation accumulation" (MA) lines. By comparing evolution at small and large N, the extent to which adaptation to substrate rigidity, and the evolution of phenotypic plasticity in general, is constrained by mutational input vs. constrained by opposing selection on correlated traits will be inferred.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.