Hydrodynamic Interactions and Cell Deformation in Neutrophil Adhesion

项目5的中心目标是了解流体剪切应力、细胞形态和细胞增殖之间的相互作用。 中性粒细胞在内皮细胞上束缚和滚动的动力学中的L-选择素表达。我们将使用一个 结合最先进的计算模拟受体介导的细胞粘附下流动，在 用分离的人中性粒细胞和嗜中性粒细胞样细胞系在良好限定的流体剪切中进行的体外实验 环境，以及与其他项目的合作投资。多粒子粘附动力学 由PI开发的模拟，使以前未解决的问题，如 非球形形状对白细胞滚动物理学的影响，以及计算和实验 L-选择素脱落和机械传感研究。众多的物理决定因素结合在一起， 控制中性粒细胞炎症募集，包括受体表达、激活状态、细胞形状、局部 流动环境，细胞与细胞之间的碰撞是高度复杂和非线性的，因此我们采取了 系统的综合工程方法来阐明这些行为。拟议的工作安排如下： 围绕三个具体目标。目的1：选择素介导的活化白细胞的束缚和滚动：在本研究中， 目的利用多粒子粘附动力学模拟活化细胞形态，并详细分析 体内观察活化细胞滚动，研究非球形细胞粘附的动力学。目标二： L-Selecfin在轧制过程中的力传递和脱落机理这一目标将探讨 在流动室实验中，用原发性中性粒细胞和 一种变异的类嗜酸性细胞系目的3：剪切诱导的对通过化学引诱剂活化的抗性 GPCR。在这个目标中，我们将研究剪切应力依赖的GPCR介导的 中性粒细胞对fMLP和血小板活化因子（PAF）的反应。总之，拟议的研究将 第一时间确定非球形白细胞的物理形状和机械响应 中性粒细胞受体在单分子水平，影响细胞束缚和滚动的动力学， 选择素-呈递内皮在生理流动下。

The central goal of Project 5 is to understand the interplay between fluid shear stress, cell morphology, and L-selectin expression on the dynamics of neutrophil tethering and rolling on the endothelium. We will use a combination of state-of-the-art computational simulations of receptor-mediated cell adhesion under flow, in vitro experiments with isolated human neutrophils and neutrophil-like cell lines in well-deflned fluid shear environments, and collaborative invesfigafion with other projects. The mulfiparticle adhesive dynamics simulafion developed by the PI, enables the invesfigafion of previously unaddressed problems such as the influence of non-spherical shape on the physics of leukocyte rolling, and computational and experimental study of L-selecfin shedding and mechanosensing. The multitude of physical determinants combining to control neutrophil inflammatory recruitment, including receptor expression, activation state, cell shape, local flow environment, and cell-cell collisions are highly complex and nonlinear and so we have taken a systematic integrated engineering approach to elucidate these behaviors. The proposed work is organized around three specific aims. Aim 1: Selecfin-Mediated Tethering and Rolling of Activated Leukocytes: In this aim we will use mulfiparticle adhesive dynamics simulafions of acfivated cell shapes, and detailed analysis of in vivo observations of activated cell rolling, to study the dynamics of non-spherical cell adhesion. Aim 2: Mechanisms of L-Selecfin Mechanotransducfion and Shedding During Rolling. This aim will explore the molecular mechanisms of mechanical shedding in flow chamber experiments with primary neutrophils and an altered neutrophil-like cell line. Aim 3: Shear-Induced Resistance to Activation via Chemoattractant GPCRs. In this aim, we will study the quantitafive dynamics of the shear stress-dependent GPCR-mediated response of neutrophils to fMLP and platelet activating factor (PAF). Together, the proposed research will determine for the first fime how the physics of nonspherical leukocyte shape, and the mechanical response of neutrophil receptors at the single molecule level, influence the dynamics of cell tethering and rolling to selecfin-presenfing endothelium under physiological flow.