MOLECULAR FORCES IN BLOOD/VASCULAR CELL ADHESION

该项目的广泛、长期目标是确定 控制胶粘剂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的黏附 功能。这些粘合剂的相互作用是装订特定的结果 整合素、免疫球蛋白(Ig)超家族和选择素的配体 受体由白细胞和血管内皮细胞表达，是中枢 血液循环中的正常和病理生理过程。五人组 特定的目标是由当代问题和专业驱动的 中性粒细胞与血管内皮细胞相互作用的不确定性 作为模型膜结构之间的相互作用，将屈服 对与所有细胞黏附相关的机制的基本见解 流程。萨L。受体-配体本征动力学表征 键解离；SA 2.关联配体受体结合和 炎症刺激对细胞力学性质转化的影响 皮质结构；SA 3.检查附着体的强度 与受体-配体亲和力的关系；SA 4.阈值的评估 模型膜中受体锚定的强度；SA 5。检查 膜位阻和静电地形对受体的影响 拔牙。方法将是物理探测结构 单个受体-配体水平上的粘附性 并测试细胞材料性质的功能变化 在分子黏附事件和趋化刺激后 探员们。将使用一种新型的超灵敏力传感器，它可以 定位为纳米级分辨率，可以测量范围内的力 从最弱化学键的强度(0.01pN)到 共价键的强度(大于或等于1000pN)。原力 传感器是一种胶囊组件，在该组件中微珠探头被化学地 粘在红细胞或合成脂质双层囊泡上，由 微型吸管，由微处理器控制的压电式平移驱动， 并通过数字化视频图像进行光学检测(衍射和 反射干涉)由微型计算机处理。使用这个传感器， 中性粒细胞、内皮细胞和转染体细胞中的单个受体 表面将通过其内源性粘附性配体进行探测， 附着在微珠上的单抗和其他配体。这 研究将建立对血液的生物物理洞察的新领域- 血管细胞黏附在分子水平上的作用 对科学理解受体的作用意义重大- 免疫功能中的中介黏附和细胞表面结构 靶向受体分子的药物的开发，以及在 在肿瘤组织中恢复足够的免疫反应将有助于 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.