Dynamics and forces during first stages of Entamoeba tissue invasion

寄生阿米巴可以导致严重的疾病，包括阿米巴病和阿米巴脑炎。对于阿米巴引起的疾病的发展，组织的入侵和破坏是必不可少的。这些过程包括阿米巴细胞通过主动运动穿过组织内的狭窄，破坏细胞外基质，杀死目标细胞和巨噬细胞增多，即阿米巴对目标细胞的咬合。因此，生化和物理机制都参与了组织侵袭的第一阶段。通过将生物物理和材料科学的实验方法与统计物理的理论方法相结合，我们计划了解这种物理和生化机制对内阿米巴的各自影响。为此，我们将建立微结构环境来研究限制对内阿米巴细胞运动的影响，从而对组织侵袭产生影响。此外，我们将监测当内阿米巴接近靶细胞时，这种细胞内运动的变化是否发生。为了研究阿米巴的生物学功能和致病潜能是否依赖于细胞内的运动，我们将注射示踪剂来量化局部流场并人为地拥挤细胞内空间，以了解细胞内拥挤是否控制(细胞内)运动以及在多大程度上控制细胞内的运动。从这些来自统计物理的测量和工具中，我们将获得对变形虫运动和内部运动之间的关联的详细见解。此外，我们还将描绘在巨噬细胞增多和组织破坏过程中力量的影响，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中和接近目标细胞时的运动，我们将使用主动移动的硬核-软壳粒子来模拟阿米巴细胞的最小模型。将这些柔软的模型细胞的确切运动模式与实验信息进行比较，我们将能够测量相关的物理参数，如阿米巴细胞施加的力，以及洞察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芯片上的器官系统，以了解在更接近体内情况下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.