Dynamics and forces during first stages of Entamoeba tissue invasion

寄生阿米巴可引起严重的疾病，包括阿米巴病和阿米巴脑炎。对于由变形虫引起的疾病的进展，组织的入侵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通过组织中的收缩，破坏细胞外基质，杀死目标细胞和噬细胞作用，即变形虫啃噬目标细胞。因此，生物化学和物理机制都参与了组织侵袭的最初阶段。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，我们计划了解这些物理机制与生物化学机制在内阿米巴虫中的各自影响。为此，我们将建立微观结构环境来研究禁闭对内阿米巴细胞运动的影响，从而对组织侵袭的影响。此外，我们将监测当内阿米巴虫接近靶细胞时，这种细胞内运动是否发生变化。为了研究变形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（细胞内）运动。从这些测量和统计物理学的工具中，我们将获得详细的见解，了解阿米巴原虫运动和内部运动的相关性。此外，我们还将描述在细胞形成和组织破坏过程中作用力的影响，例如，通过牵引力显微镜。为了更深入地了解阿米巴原虫在收缩和接近靶细胞时的运动，我们将使用主动移动的硬核-软壳颗粒模拟阿米巴原虫细胞的最小模型。将这些黏性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，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，以了解内阿米巴原虫在更接近体内情况下入侵的物理原理。

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.