Dynamic Strenghts of Leukoctye Adhesion Bonds

我们的长期目标是发展对白细胞黏附的详细生物物理理解。 分子水平，将粘接强度与化学相互作用联系起来，并确定如何粘合 结合应力通过细胞膜传递到受体尾部和受体之间的内部连接 它可以影响特定生化途径的细胞细胞结构。我们目前的研究提供了 对白细胞粘附键的机械强度及其在力作用下的动力学有重要的见解， (I)首先用于唾液粘蛋白配体PSGL-1与启动白细胞的选择素之间的相互作用 血管壁附着物，(Ii)超级免疫球蛋白(Ig)家族配体之间的第二种相互作用 以及整合素，发出信号并稳定白细胞黏附，使其能够迁移到组织中。我们有 开发了将配体固定在超灵敏测力探针尖端的新方法，并测试了 固定在微球上或表达在微球上的受体的单个键的机械强度 细胞。利用一种令人兴奋的新方法和已建立的细胞系，在受体- 细胞骨架相互作用，这个应用程序的主要目标是“在细胞内移动”，首先 确定细胞结构蛋白调节粘连机械强度的程度 复杂，然后确定这些连接在白细胞信号中所起的机械作用 对于招募到炎症和损伤部位非常重要的过程。这些研究旨在测试 三个假设。假设：白细胞选择素和整合素的相互作用具有功能特异性 在电池内部低应力条件下控制键形成和释放的机械设计- 表面接触，从而影响粘结扩散，并决定最初粘合事件的命运。 假设：分子粘合复合体的机械强度受最弱的一环控制 从外部粘附键到连接的内部键的整个蛋白质相互作用序列 受体-尾部结构域到细胞细胞结构。假设：锚定整合素黏附的连接 复杂的细胞结构是“由外而内”和“由内而外”信号传导的关键机械效应器。 白细胞是调节黏附强度的重要反馈过程。

Our long-term objective is to develop a detailed biophysical understanding of leukocyte adhesion at the molecular level, relating adhesive bond strength to chemical interactions and establishing how adhesive bond stress is transmitted through the cell membrane to the interior connections between receptor tails and the cell cytostructure where it can impact specific biochemical pathways. Our current research has provided significant insight into the mechanical strengths of leukocyte adhesion bonds and their kinetics under force, (i) first for interactions between the sialo mucin ligand PSGL-1 and selectins that initiate leukocyte attachments to vessel walls, (ii) second for interactions between super immunoglobulin (Ig)family ligands and integrins that signal and stabilize leukocyte adhesion enabling emigration into tissues. We have developed novel methods to immobilize ligands on the tip of ultrasensitive force probes and test the mechanical strengths of individual bonds to receptors either immobilized on microspheres or expressed on cells. Exploiting an exciting new approach and established cell lines with strategic alterations in receptor- cytoskeletal interactions, the principal objective of this application is to "move inside the cell", first establishing the extent to which cytostructural proteins regulate the mechanical strength of an adhesion complex, and then determining the mechanical role that these linkages play in the leukocyte signalling processes important for recruitment to sites of inflammation and injury. The studies are designed to test three hypotheses. Hypothesis: leukocyte selectin and integrin interactions have function-specific mechanical designs that govern bond formation and release under conditions of low stress interior to a cell- surface contact, thereby impacting bond proliferation and determining the fate of the initial adhesion event. Hypothesis: mechanical strengths of molecular adhesion complexes are governed by the weakest link in entire sequence of protein interactions from the outside adhesive bond to the inside bonds that connect receptor-tail domains to the cell cytostructure. Hypothesis: the linkages that anchor an integrin adhesion complex to the cell structure are key mechanical effectors of "outside-in" and "inside-out" signaling in leukocytes and represent an important feed-back process to regulate adhesion strength.