Dynamics and forces during first stages of Entamoeba tissue invasion

寄生性变形虫可引起严重疾病，包括变形虫病和变形虫脑炎。对于由阿米巴引起的疾病的进展，组织侵入和破坏是必不可少的。这些过程包括变形虫细胞通过主动运动穿过组织中的缩窄部、细胞外基质的破坏、靶细胞的杀伤和胞穿孔，即，阿米巴对靶细胞的啃噬。因此，生物化学和物理机制都参与了组织入侵的第一阶段。通过将生物物理学和材料科学的实验方法与统计物理学的理论方法相结合，我们计划了解内阿米巴中这种物理机制与生物化学机制的各自影响。为此，我们将建立微结构环境，以研究限制对内阿米巴细胞运动的影响，从而对组织入侵。此外，我们将监测这种细胞内的运动是否发生变化时，内阿米巴接近靶细胞。为了研究阿米巴原虫的生物学功能和致病潜力是否取决于细胞内运动，我们将注射示踪剂来量化局部流场并人工拥挤细胞内空间，以观察细胞内拥挤是否以及在多大程度上控制（内）细胞运动。从这些测量和统计物理学的工具，我们将获得详细的见解和内部的阿米巴运动的相关性。此外，我们还将描述在胞啃和组织破坏期间力的影响，例如，通过牵引力显微镜。为了更深入地了解内阿米巴在收缩处的运动，当接近目标细胞时，我们将使用积极移动的硬核软壳颗粒来模拟阿米巴细胞的最小模型。将这些黏糊糊的模型细胞的确切运动模式与实验信息进行比较，我们将能够测量所涉及的物理参数，例如阿米巴细胞施加的力，以及深入了解内阿米巴运动的主要指导原则。从长远来看，我们计划将我们的研究扩展到器官芯片系统，以了解更接近体内情况的内阿米巴入侵的物理原理。

Parasitic amoebae can cause severe diseases, including amoebiasis and amoeba encephalitis. For the progression of diseases caused by amoeba, tissue invasion and destruction are essential. These processes include the passage of amoeba cells through constrictions in the tissue by active motion, the destruction of the extracellular matrix, the killing of target-cells and trogocytosis, i.e., the gnawing of amoeba on target-cells. Hence, both biochemical and physical mechanisms are involved in the first stages of tissue invasion. By combining experimental methods from biophysics and materials science with theoretical approaches from statistical physics, we plan to understand the respective impact of such physical versus biochemical mechanisms in Entamoeba. To do so, we will set up microstructured environments to investigate the impact of confinement on the motion of Entamoeba cells and thus on tissue invasion. Moreover we will monitor if changes of this intracellular motion occur when the Entamoeba approach target-cells. To investigate whether the biological function and pathogenic potential of the amoebae depends on intracellular motion, we will inject tracers to quantify local flow fields and to artificially crowd the intracellular space in order to see if and to what extent intracellular crowding controls (intra)cellular motion. From these measurements and tools from statistical physics we will gain detailed insights into the correlation of motion of and inside the amoeba. In addition, we will also delineate the impact of forces during trogocytosis and tissue destruction, e.g., by traction force microscopy. To gain a deeper understanding of Entamoeba motion in constrictions and when approaching target-cells we will simulate minimal models for amoeba cells using actively moving hard core-soft shell particles. Comparing the exact motion patterns of these squishy model cells with the experimental information we will be able to gauge the involved physical parameters such as the force exerted by the amoeba cells, as well as gain insight into the main guiding principles of Entamoeba motion. In the long run we plan to extend our studies to organ-on-a-chip systems to understand the physical principles of Entamoeba invasion in situations closer to the in vivo situation.