Collaborative Research: Theory and experiment of contact inhibition of locomotion in nanofiber geometries

合作研究：纳米纤维几何形状中接触抑制运动的理论与实验

基本信息

批准号：
2119949
负责人：
Amrinder Nain
金额：
$ 74.7万
依托单位：
Virginia Polytechnic Institute and State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2025-07-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2119949&HistoricalAwards=false
关键词：
Collaborative Research Theory experiment contact

项目摘要

Multicellular organisms are composed of various types and numbers of cells that must work together and coordinate their movement under various conditions. Moreover, cells must do this inside an organism – a complex 3D environment unlike the common 2D environment of Petri dishes. This project studies how cells can coordinate their motion in a more natural environment: crawling along a protein-coated fiber, like a tightrope walker. The project combines experiments and theory to study the physical and biological factors that control what happens when cells contact each other on these fibers. On 2D surfaces cells reverse their migration direction upon contacting each other, a phenomenon described in the 1950s. Termed contact inhibition of locomotion (CIL), numerous studies have shown CIL outcomes to depend upon cell type. The Camley-Nain collaboration has recently shown CIL outcomes to be qualitatively different on suspended fibers than those described on flat 2D. Thus, understanding how realistic environments control cellular interactions is an essential step to improved understanding of these biological processes. One approach in this project will be to understand how much cells stick to each other and how much they stick to the fiber by measuring the force required to pull them apart. Another will be to study whether, when two cells collide and one turns around, the cell that turns around is the cell that is moving slower, the cell that is smaller, or some other factors like if one cell has long or asymmetric tendrils. The project will also study proteins inside a cell that determine which direction a cell will protrude its front (polarity proteins) and see how this polarity changes when cells contact each other. The Broader Impact of the work includes the intrinsic merit of the research as coordinated cellular movement is important for such processes as wound healing and normal development. Additional activities involve online outreach and training students to write for a broad audience. Online games based on predicting the outcome of cell-cell collisions will be built, to give an unusual view of cell biology and physics to the wider public.In many biological contexts, including wound healing, development, and cancer metastasis, eukaryotic cells migrate collectively, with coherent motion emerging from cell-cell interactions. A prototypical example of a cell-cell interaction is contact inhibition of locomotion (CIL), in which contacting cells repolarize away from that contact. CIL has been long studied in cells on flat substrates, but the Nain-Camley collaboration recently discovered that CIL is qualitatively different in cells on suspended fibers, which more closely resemble extracellular matrix. How do large changes in CIL arise only from new physical geometry? What physical factors are most predictive of the outcomes of cell-cell collisions? Answering these questions requires predictive models of CIL coupled with experiments on tightly-controlled and biologically relevant matrices. This matches the experience of the Camley group (computational models of Rho GTPase polarity, motility, and CIL) with that of the Nain group (precisely defined suspended fiber environments and mechanobiology). This collaborative project studies CIL in fibrous environments by: 1) Studying the effect of mechanical forces on cell-cell interactions, 2) Developing a data-driven method to predict the outcomes of cell-cell collisions, and 3) Understanding the link between Rho GTPase polarity, cell shape, and CIL. Existing physical models of cell-cell interactions will be parametrized and extended based on measurements of cell-cell and cell-substrate adhesion. Adhesion will be quantified by pulling experiments using nanonet force microscopy. The project will develop tools to predict which cell turns around when two cells collide (is it the slowest, the least polarized, the smallest?) and determine how can this be reliably controlled. To predict this outcome, the collaboration will integrate observations of hundreds of collision outcomes into a data-driven statistical model to determine the crucial controlling factors. To understand how a small contact between cells is transduced into a decision to repolarize, the collaboration will study Rac polarity in cell collisions. The initial steps of repolarization will be experimentally characterized by Rac activity measurements with FRET reporters, and the degree of repolarization post-contact will be measured and calibrated between model and experiment. This will be combined with understanding how CIL differs from cell type to cell type to understand if behaviors are qualitatively different between different cell types, and if so, how.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.

多细胞生物由各种类型和数量的细胞组成，这些细胞必须在各种条件下协调并协调其运动。此外，细胞必须在组织内部执行此操作 - 与培养皿的常见2D环境不同，一个复杂的3D环境。该项目研究细胞如何在更自然的环境中协调其运动：沿着蛋白质涂层的纤维爬行，例如钢丝Walker。该项目结合了实验和理论，以研究控制细胞在这些纤维上相互接触时发生的事情的物理和生物学因素。在二维表面上，细胞相互接触时扭转了它们的迁移方向，这是1950年代描述的现象。称为运动的接触抑制（CIL），许多研究表明CIL的结果取决于细胞类型。 Camley-Nain的合作最近显示，在悬浮纤维上，CIL结果在质量上有所不同。这是，了解现实环境如何控制细胞相互作用是改善对这些生物过程的理解的重要步骤。该项目中的一种方法是了解彼此粘附多少，以及它们通过测量将它们拉开所需的力来粘在纤维上的程度。另一个将是研究两个细胞碰撞和一个转动时，转弯的细胞是移动较慢的细胞，较小的细胞，或其他一些因素，例如一个细胞长或不对称卷须。该项目还将研究细胞内的蛋白质，该蛋白质确定一个细胞将伸出其正面的方向（极性蛋白），并查看这种极性在彼此接触时如何变化。这项工作的更广泛的影响包括研究的内在优点，因为协调的细胞运动对于诸如伤口愈合和正常发育等过程很重要。其他活动涉及在线外展和培训学生为广泛的受众写作。将建立基于预测细胞细胞碰撞结果的在线游戏，以向更广泛的公众提供对细胞生物学和物理学的不寻常视野。在许多生物学环境中，包括伤口愈合，发育和癌症转移，真核细胞集体迁移，并从细胞电池相互作用中出现相干运动。细胞 - 细胞相互作用的原型示例是运动的接触抑制（CIL），其中接触细胞从该接触中重复降解。 CIL在平坦底物的细胞中长期研究了，但是Nain-Camley的合作最近发现CIL在悬浮纤维上的细胞中截然不同，悬浮的纤维上的细胞较大，这更类似于细胞外基质。 CIL的大变化仅来自新的物理几何形状？哪些物理因素最可预测细胞细胞碰撞的结果？回答这些问题需要CIL的预测模型，并在紧密控制和生物学相关的物质上进行实验。这将Camley组（Rho GTPase极性，运动性和CIL的计算模型）与NAIN组（精确定义的悬浮纤维环境和机制）的体验相匹配。该协作项目在纤维环境中研究CIL：1）研究机械力对细胞 - 细胞相互作用的影响，2）开发一种数据驱动的方法来预测细胞细胞碰撞的结果，3）理解Rho GTPase极性，细胞形状和CIL之间的联系。现有的细胞 - 细胞相互作用的物理模型将根据细胞细胞和细胞覆盖物的测量值进行参数化和扩展。通过使用纳米力显微镜拉动实验来量化粘附。该项目将开发工具，以预测两个细胞碰撞时哪个细胞转动（这是最慢的，最小的，最小的，最小的？），并确定如何可靠地控制这一点。为了预测这一结果，该协作将将数百个碰撞结果的观察结果整合到数据驱动的统计模型中，以确定关键的控制因素。为了了解细胞之间的少量接触被转化为复制的决定，该协作将研究细胞碰撞中的RAC极性。重复化的初始步骤将通过用FRET报告者进行RAC活性测量，并在模型和实验之间测量和校准。这将结合了解CIL从细胞类型到细胞类型的不同之处，以了解不同细胞类型之间的行为是否在质量上不同，如果是的，则该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛的审查标准通过评估来进行评估的。