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，在软性表面(底物)上培养时，在增殖、细胞死亡、分化、细胞铺展和迁移程度等方面与硬底物相比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的特征，包括细胞骨架组织、染色质紧凑和基因表达。这个项目将使用实验技术来揭示真核体细胞(构成有机体的细胞)适应其微环境的机械刚性的潜在进化规则，即我们所说的机械进化。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，这可能会在细胞力学和进化细胞生物学领域产生新的方向。此外，该项目将促进对生物材料作为设计体细胞的工具的实验进化的欣赏。该项目将为本科生、高中生和一名化学工程专业的女研究生提供培训机会。该项目希望发现两条基本规则。规则1：表型可塑性。以前适应于刚性粘附性底物的小鼠成纤维细胞的复制群体将被允许在不同刚性的底物上进化。复制的细胞群体将在严格控制刚性的底物上连续培养和传代两年(~360-500代，传代时N~1000个细胞)。是否以及如何在生物组织的不同水平上一致地选择一套细胞特征的基质机械特性将被调查。规则2：突变输入。复制群体将保持如上所述，除非群体规模很小(传代时为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的进化，可以推断出对底物刚性的适应和表型可塑性的进化在多大程度上受到突变输入的限制，而不是受到相关性状上相反选择的限制。该奖项反映了NSF的法定使命，并通过使用基金会的智力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.