Controlling collective behavior in eukaryotic cell populations

描述（由申请人提供）：该提案的总体目标是了解单细胞的非线性时空动力学如何在社会性阿米巴盘基网柄菌的多细胞阶段产生连贯行为。我们将通过高精度测量和数学建模的结合来实现这一目标。在这个系统中，饥饿的变形虫参与发育计划作为替代生存策略。单个细胞通过信号分子 cAMP 进行通讯，cAMP 可作为趋化性信号，导致细胞聚集并形成多细胞粘菌。该提案的具体目标是 (1) 获得单细胞 cAMP 信号传导的定量描述，(2) 了解单细胞梯度传感及其与 cAMP 信号传导的关系，以及 (3) 开发一个多细胞模型，概括在盘基网柄菌细胞群体中观察到的集体行为。开发这些模型将回答三个基本问题：表征细胞 cAMP 信号动力学的单个细胞的基本自由度是多少？细胞外梯度传感与胞质 cAMP 水平有何关联？如何从细胞内和细胞间 cAMP 信号传导动力学推断大规模多细胞时空信号传导模式和细胞聚集？回答这些问题将扩大我们对分子信号传导和细胞相互作用如何导致集体多细胞行为的理解，并最终指导我们找到控制此类行为的方法。从实用的角度来看，该提案建立在我们发明的一套新方法的基础上，这些方法使我们能够成功监测单个细胞中信号分子 cAMP 的细胞内和细胞外浓度。社会变形虫为实验驱动的定量建模提供了独特的机会，因为它们允许在单细胞和多细胞水平上同时进行测量；细胞可以被限制在高度可控的微流体环境中，并且可以从遗传数据库中获得大量信号和聚集突变体。从广泛的角度来看，这项研究可能会产生新的实验和定量工具，用于分析细胞间信号传导以及新出现行为的单细胞到多细胞的转变。 公共健康相关性：最近的研究表明，细胞间通讯产生的细胞集体行为普遍存在，并且对于生物体的生存至关重要。当个体细胞群体合作时，集体的行为不容易从个体的行为中推断出来。在某些情况下，集体互动可能会被癌症等恶性现象劫持。因此，迫切需要了解这些集体行为。最终目标是重新编程细胞群体的集体行为。这种方法有可能促进新疗法的发展，例如通过免疫细胞直接引导免疫反应或靶向肿瘤以防止其扩散。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to understand how nonlinear spatio-temporal dynamics of single cells give rise to coherent behaviors at the multi-cell stage in the social amoeba Dictyostelium discoideum. We will achieve this through a combination of high-precision measurements and mathematical modeling. In this system, starved amoebae engage in a developmental program as an alternate survival strategy. Individual cells communicate via the signaling molecule cAMP, which serves as a cue for chemotaxis that leads cells to aggregate and form a multi-cellular slime mold. The specific goals of this proposal are (1) to obtain a quantitative description for single cell cAMP signaling, (2) to understand single cell gradient sensing and its relationship to cAMP signaling, and (3) to develop a multi-cell model that recapitulates observed collective behaviors in Dictyostelium cell populations. Developing these models will answer three fundamental questions: What are the essential degrees of freedom of individual cells that characterize the cell's cAMP signaling dynamics? How extra-cellular gradient sensing is linked to cytosolic cAMP levels? How can large-scale multi- cellular spatio-temporal signaling patterns and cellular aggregation be inferred from intra- and inter-cellular cAMP signaling dynamics? Answering these questions will expand our understanding of how molecular signaling and cellular interactions lead to collective multi-cellular behaviors, and ultimately guide us to find ways to control such behaviors. From a practical point of view, this proposal builds on a new set of methods we have invented that have enabled us to successfully monitor both intra- and extra-cellular concentrations of the signaling molecule cAMP in individual cells. Social amoebae provide a unique opportunity for experiment- driven quantitative modeling because they allow for measurements simultaneously at the single cell and at the multi-cell levels; cells can be confined into highly controllable microfluidic environments and numerous signaling and aggregation mutants are available from a genetic databank. From a broad perspective, the research is likely to yield new experimental and quantitative tools for analyzing cell-to-cell signaling and the single-to-multi-cell transition of novel emergent behaviors. PUBLIC HEALTH RELEVANCE: Recent research reveals that cellular collective behaviors emerging from cell-to-cell communication are both ubiquitous and essential for the organism's survival. When groups of individual cells cooperate, the behavior of the collective is not easily deduced from the behavior of the individuals. In some cases, collective interactions can be hijacked by malign phenomena such as cancer. Hence there is a crucial need to understand these collective behaviors. The ultimate goal is to reprogram collective behaviors in cellular populations. This approach has the potential to promote novel therapies by, for example, directly guiding immune responses via immune cells or targeting tumors to prevent them from spreading.