Quantitative Study of T-cell Polarization

描述(由申请者提供)：本项目的目标是将我们对T细胞极化的理解建立在坚实的量化基础上。免疫系统的T细胞极化，即定位于它们的目标，例如被感染的或要被清除的肿瘤细胞。T细胞极化的关键部分是中心体朝向靶点的重新定位。虽然已经确定了许多参与调控这一过程的分子途径，但对于这一过程本身的机制，甚至缺乏普遍的了解。新的数据引导我们假设，与公认的概念相反，基本机制是整个细胞与靶接触时的运动和变形，这是一个指向整个细胞结构优化的过程。首先，我们将使用一个简化的平面仿生底物刺激T细胞的实验系统来阐明中心体重新定位的基本特征。这将通过将计算建模与定量、多维、活细胞显微镜相结合来实现。接下来，通过用这些过程的特定数值模型丰富基本模型，并将预测与调节特定分子活动的实验进行比较，将确定特定的力产生的细胞内过程(分子马达、细胞骨架动力学)对中心体易位的贡献。最后，我们将利用对适用于高通量测量的简化系统的理解，通过计算将我们的知识外推到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添加到计算机模型中的细胞-细胞相互作用中发现的额外特征来验证。该项目的结果将不仅是对免疫细胞中心体极化这一具有生物医学意义的现象的严格理解，并在预测性计算机模型中形式化，而且还将对定量生物医学研究的新方法进行实质性的经验改进。

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.