Biomechanics on Neutrophil Rolling on the Endothelium

中性粒细胞在内皮上滚动的生物力学

基本信息

批准号：
6732081
负责人：
JIN-YU SHAO
金额：
$ 30.6万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-04-01 至 2007-03-31
项目状态：
已结题

项目摘要

The rolling of human neutrophils on the endothelium is only an initial step of their extravasation, but it is a complicated dynamic process mediated cooperatively by the adhesion molecules expressed on the surfaces of endothelial cells and neutrophils, the shear stresses due to the blood flow, and the mechanical properties of the neutrophil/endothelial cell membranes and neutrophil microvilli. Therefore, the overall goal of this proposal is to investigate the details of these mechanical properties and how they will impact on the rolling process. The specific aims are to: 1) extract "single tethers to test the hypotheses that single tether formation from endothelial cells is a local phenomenon (i.e., it does not depend upon whether the cell is suspended or attached to a substrate, nor the surface receptor type used to form the tether), single tether formation from endothelial cells is modulated by stimulation, and single tethers can be extracted simultaneously from passive neutrophils and stimulated endothelial cells, 2) extract double tethers to test the hypotheses that double tether formation from human neutrophils or endothelial cells is modulated by stimulation, and double tethers can be extracted simultaneously from passive neutrophils and stimulated endothelial cells, 3) quantify the mechanical properties of a single neutrophil microvillus to test the hypotheses that the microvillus has different static properties in bending and compression compared with extension, and its viscoelastic properties are not significant during extension or compression, and 4) develop a biomechanical model to test the hypotheses that simultaneous tether formation from neutrophils and endothelial cells, compared with tether formation from neutrophils alone, further facilitates the rolling of neutrophils on the endothelium, and stimulating both neutrophils and endothelial cells, compared with stimulating neutrophils alone, also further facilitates the rolling of neutrophils on the endothelium. Tether formation from neutrophils and suspended endothelial cells will be performed with the micropipette aspiration technique, while tether formation from attached endothelial cells will be performed with the atomic force microscope. The microvillus mechanics will be studied with the optical tweezers, combined with the micropipette manipulation system.

人类嗜中性粒细胞在内皮上的滚动只是其渗出的初始步骤，但这是一个复杂的动态过程，由在内皮细胞和嗜中性粒细胞的表面上表达的粘附分子介导，是血液流动引起的剪切应力，以及中性粒细胞和胞质的机械性和中性粒细胞和中性粒细胞和中性粒细胞的机械性能。因此，该提案的总体目标是研究这些机械性能的细节以及它们将如何影响滚动过程。具体目的是：1）提取“从内皮细胞中的单个束缚形成的假说是一种局部现象（即，它不取决于细胞悬浮或附着在底物上或连接到底物，也不取决于用于形成束带的表面受体类型的单个TETHER的刺激性刺激物，是由刺激性刺激的单个TETHERERAINT，是由内皮刺激的单个Tether构成的，中性粒细胞和受刺激的内皮细胞，2）提取双重系以测试假设，该假说是通过刺激调节人类中性粒细胞或内皮细胞的双线线形成，并可以从被动中性细胞和刺激的内皮细胞中同时提取双膜，以量化单个中性粒细胞，3）与扩展相比，弯曲和压缩的不同静态特性及其粘弹性在延伸或压缩过程中并不重要，4）开发一种生物力学模型，以测试中性粒细胞和内皮细胞同时形成的假设，与单独的中性粒子相比，中性粒细胞的螺旋形成了中性粒子，并在中性粒子中呈现中性，并在中性粒子上呈现中性层状。与单独刺激性嗜中性粒细胞相比，内皮细胞和内皮细胞也进一步促进了内皮上嗜中性粒细胞的滚动。将使用微孔抽吸技术进行嗜中性粒细胞和悬浮的内皮细胞的系绳形成，而附着的内皮细胞的系绳形成将使用原子力显微镜进行。将使用光学镊子研究微绒毛机械师，并结合微型移动系统。