MOLECULAR FORCES IN BLOOD/VASCULAR CELL ADHESION

该项目的广泛，长期目标是确定 控制粘附相互作用的亚微观物理因素 白细胞和血管内皮细胞及其与细胞偶联粘附 功能这些粘附相互作用是结合特异性的结果。 整合素、免疫球蛋白（IG）超家族和选择素的配体 受体表达的白细胞和内皮细胞，是中央 血液循环中的正常和病理生理过程。五 具体的目标是由当代问题和主要的动机 中性粒细胞-血管内皮细胞相互作用的不确定性 由于模型膜结构之间的相互作用，将产生 对所有细胞粘附相关机制的基本见解 流程.沙湖表征受体-配体的内在动力学 键解离; SA 2.为了关联配体受体结合和 炎症刺激对细胞力学性质的改变 皮质结构; SA 3.检查附件的强度， 与受体-配体亲合力的关系; SA 4.评估阈值 模型膜中受体锚定强度; SA 5.审查 膜立体和静电形貌对受体影响 萃取该方法将是物理探测结构 在单个受体-配体水平上参与粘附的性质 复合物和测试细胞材料性质的功能变化 在分子粘附事件和趋化性刺激之后， 剂.将使用一种新型的超灵敏力传感器， 定位在纳米级的分辨率，可以测量力的范围， 从低于最弱化学键的强度（0.01 pN）到 共价键强度（大于或等于1000 pN）。的力 传感器是一种胶囊组件，其中微珠探针被化学地 粘在红细胞或合成脂质双层囊泡上， 微吸管抽吸，由微处理器控制的压电平移驱动， 并通过数字化视频图像（衍射和 反射干涉）。使用这个传感器， 中性粒细胞、内皮细胞和转染细胞中的单个受体 表面将通过其内源性粘附配体，特异性 单克隆抗体和其它附着于微珠的配体。这 研究将建立一个新的领域，生物物理学洞察血液- 血管细胞粘附在分子水平，并将有助于 对科学认识受体的作用有重要意义- 介导的粘附和细胞表面结构的免疫功能， 开发靶向受体分子的药物， 在肿瘤组织中恢复足够的免疫反应， 免疫疗法在癌症治疗中的应用

The broad, long term goal of this project is to determine the submicroscopic physical factors that govern adhesive interactions between leukocytes and vascular endothelial cells and that couple adhesion to cell function. These adhesive interactions are consequences of binding specific ligands to integrin, immunoglobulin (Ig) super family, and selectin receptors expressed by leukocytes and endothelial cells, and are central to normal and pathophysiological processes in blood circulation. The five Specific Aims are motivated by contemporary questions and major uncertainties in neutrophil-vascular endothelial cell interactions as well as interactions between model membrane structures and will yield fundamental insights into mechanisms relevant to all cell adhesion processes. SA l. To characterize intrinsic kinetics of receptor-ligand bond dissociation; SA 2. To correlate ligand receptor binding and inflammatory stimuli to transformations in mechanical properties of cell cortical structures; SA 3. To examine the strength of attachments in relation to receptor-ligand avidity; SA 4. To evaluate the threshold strength for receptor anchoring in model membranes; SA 5. To examine the influence of membrane steric and electrostatic topography on receptor extraction. The approach will be to physically probe the structural properties involved in adhesion at the level of the single receptor-ligand complexes and to test functional changes in cell material properties subsequent to molecular adhesion events and stimulation by chemotactic agents. A novel ultrasensitive force sensor will be used that can be positioned with nanoscale resolution and can measure forces over a range from below the strength of the weakest chemical bonds (0.01 pN) up to the strength of covalent bonds (greater than or equal to 1000 pN). The force sensor is a capsular assembly in which a microbead probe is chemically glued to a red blood cell or a synthetic lipid bilayer vesicle held by micropipet suction, driven by microprocessor-controlled piezo translation, and detected optically by digitized video images (diffraction and reflection interference) processed by microcomputer. Using this sensor, individual receptors in neutrophil,endothelial and transfected cell surfaces will be probed by their endogenous adhesive ligands, specific monoclonal antibodies and other ligands attached to the microbead. This research will establish a new realm of biophysical insight into blood- vascular cell adhesion at the molecular level and will contribute significantly to scientific understanding of the roles of receptor- mediated adhesion and cell surface structure in immune function, the development of drugs that target receptor molecules, and in the restoration of sufficient immune responses in tumor tissues that will aid immunotherapy in cancer treatment.