Understanding the control mechanisms of 3D cell migration from new dimensions

三维组织空间中的细胞迁移对于人类生物学具有根本的重要性。然而，预测和 尽管对分子机制有了明确的认识，但编程3D细胞运动仍然是主要的挑战 涉案填补了蛋白质-蛋白质等大量亚细胞细节之间的知识空白， 相互作用，以及组织空间中不同细胞类型所表现出的迷人的动态模式，我将重点关注 中尺度细胞动力学，即细胞在3D细胞外基质中的迁移模式转变 （ECM）。我的实验室开发了基于深度学习的图像后处理，以跟踪细胞的迁移模式。 我们还开发了在细胞尺度上操纵和测量ECM微观力学的技术。基于 在此基础上，本文将系统地研究三维细胞的内在和外在调控机制 胶原ECM中的迁移模式转变。结果将铺平道路，我的长期目标，以了解 引导分子产生生命的组织原理，并为组织中的应用程序编程细胞运动性 工程和癌症治疗。为此，我将把我的实验室致力于以下研究重点。推力1 旨在确定细胞迁移模式的转换是如何受到外部线索以及内在状态的调节的 上皮-间充质转化（EMT）。我将检验三个假设， ECM微机械刚度、各向异性、塑性、机械和化学引导的协同作用，以及 作为调节细胞迁移模式转变的EMT阶段。我会用先进的电子对抗工程 和我实验室开发的表征技术。我也会用基因工程细胞 转录因子是荧光标记的并且可以被特异性激活。推力1的完成将建立 三维细胞迁移作为一个隐马尔可夫过程在中尺度动态，即迁移模式 过渡，提供了一个统一的框架，以解释不同的动态模式的3D细胞迁移中观察到的 vivo.推力2的目的是设计策略，通过非平稳的机械线索编程细胞迁移。在 子项目1，我将采用在我的实验室开发的技术来控制空间中的3D接触引导线索， 真实的时间。通过测量步进递增接触指导下的迁移模式转换，我将获得 分隔不同模式的能量屏障。然后在周期性的机械刺激下，我将测量， 计算模型的非平衡模式转换通量，统计物理量，告知 细胞运动反应的效率和能量耗散。这些中尺度量揭示了 潜在的分子组织原理。在子项目2中，我将开发胶原ECM， 使用DNA接枝的纳米颗粒作为交联剂对应力的响应。我会设计DNA序列 交联剂的屈服强度，从而对单个细胞和集体细胞的细胞迁移模式进行编程 类器官迁移推力2的完成将拓展工程化电子对抗的设计空间， 用于三维细胞运动的机械编程。

Cell migration in 3D tissue space is of fundamental importance for human biology. However, predicting and programming 3D cell motility remain as major challenges despite of a firm picture of the molecular machineries involved. To fill the knowledge gap between the overwhelming subcellular details such as protein-protein interactions, and the fascinating dynamic patterns exhibited by different cell types in tissue spaces, I will focus on the mesoscale cellular dynamics, namely the migration mode transitions of cells in 3D extracellular matrix (ECM). My lab has developed deep-learning based image postprocessing to track the migration modes of cells. We also developed techniques to manipulate and measure the micromechanics of ECM at cellular scale. Based on these preliminary results, I will systematically study the intrinsic and extrinsic control mechanisms of 3D cell migration mode transitions in collagen ECM. The results will pave the way for my long-term goals to understand the organizing principle that lead molecules to life, and to program cell motility for applications in tissue engineering and cancer treatment. To this end, I will dedicate my lab to the following research thrusts. Thrust 1 aims to determine how cell migration mode transitions are regulated by external cues, as well as intrinsic states of cells during the Epithelial-Mesenchymal Transition (EMT). I will test three hypotheses that elucidate the roles of ECM micromechanical stiffness, anisotropy, plasticity, synergy of mechanical and chemical guidance, as well as EMT stage in modulating the cell migration mode transitions. I will employ sophisticated ECM engineering and characterization techniques developed in my lab. I will also use genetically engineered cells whose EMT transcription factors are fluorescent labeled and can be specifically activated. Completion of thrust 1 will establish 3D cell migration as a hidden Markov process where the mesoscale dynamics, namely the migration mode transitions, provides a unifying framework to explain diverse dynamic patterns of 3D cell migration observed in vivo. Thrust 2 aims to devise strategies to program cell migration via nonstationary mechanical cues. In subproject 1, I will employ techniques developed in my lab to control 3D contact guidance cues in space and in real time. By measuring the migration mode transitions under step-increasing contact guidance, I will obtain the energy barriers that separate different modes. Then under periodic mechanical stimuli I will measure and computationally model the nonequilibrium mode transition flux, a statistical physics quantity that inform the efficiency and energy dissipation of cell motility responses. These mesoscale quantities shed light to the underlying molecular organizing principles. In subproject 2 I will develop collagen ECM which exhibits digital response to stresses using DNA-grafted nanoparticles as crosslinkers. I will design the DNA sequence to control the yield strength of crosslinkers, thereby programing cell migration mode both for single cell and for collective organoid migration. Completion of thrust 2 will expands the design space of engineered ECM, laying a foundation for the mechanical programing of 3D cell motility.