Quantitative Study of T-cell Polarization

描述（由申请人提供）：该项目的目的是将我们对T细胞极化的理解建立在坚实的定量基础上。免疫系统的T细胞极化，即使自己朝向目标，如要消灭的感染细胞或肿瘤细胞。T细胞极化的关键组成部分是中心体向目标重新定向。虽然已经确定了一些参与这一过程调节的分子途径，但对这一过程本身的机制甚至缺乏一般的理解。新的数据使我们假设，与公认的观念相反，基本机制是全细胞与目标接触时的运动和变形，这是一个指向全细胞结构优化的过程。首先，我们将采用平面仿生基质刺激T细胞的简化实验系统来阐明中心体重定向的基本特征。这将通过计算模型与定量、多维、活细胞显微镜的结合来实现。接下来，将通过用这些过程的特定数值模型丰富基本模型，并将预测结果与特定分子活动被调节的实验结果进行比较，来确定产生特定力的细胞内过程（分子马达、细胞骨架动力学）对中心体易位的贡献。最后，我们将利用对简化系统的理解来适应高通量测量，以计算外推我们的知识到T细胞-靶细胞相互作用的实际情况。这些预测将通过定量显微镜和在细胞-细胞相互作用中发现的附加特征添加到计算机模型中进行测试。该项目的成果将不仅是对免疫细胞中中心体极化的生物医学意义现象的严格理解，并在预测计算机模型中形式化，而且是定量生物医学研究新方法的实质性经验改进。

DESCRIPTION (provided by applicant): The objective of this project is to put our understanding of T cell polarization on a firm quantitative basis. T cells of the immune system polarize, i.e. orient themselves, toward their targets, such as infected or tumor cells to be eliminated. The crucial component of the T cell polarization is reorientation of the centrosome toward the target. Although a number of molecular pathways involved in regulation of this process have been identified, even a general understanding is lacking as to the mechanism of the process itself. New data lead us to hypothesize, contrary to the accepted notion, that the basic mechanism is whole-cell movement and deformation on contact with the target, a process directed toward whole-cell structural optimization. First, we will employ a simplified experimental system of T cells stimulated with planar biomimetic substrates to elucidate the basic features of the centrosome reorientation. This will be achieved through combination of computational modeling with quantitative, multidimensional, live-cell microscopy. Next, the contribution of specific force-generating intracellular processes (molecular motors, cytoskeletal dynamics) to the centrosome translocation will be determined by enriching the basic model with specific numerical models of these processes and comparing the predictions with experiments in which the specific molecular activities are modulated. Lastly, we will use the achieved understanding of the simplified system amenable to high- throughput measurements to extrapolate our knowledge computationally to the realistic case of the T cell- target cell interaction. The predictions will be tested by means of quantitative microscopy and the additional features found in the cell-cell interactions added to the computer model. The outcome of the project will be not only rigorous understanding of the biomedically significant phenomenon of centrosome polarization in the immune cells, formalized in a predictive computer model, but also a substantial empirical improvement of the new methodology of quantitative biomedical research.