RESPONSE OF ENDOTHELIAL CELLS TO CELL-CELL CONTACT

细胞间的接触在内皮细胞的正常功能中起着重要作用。细胞之间的接触不仅作为密封血管的物理屏障，而且还改变了这些细胞的解剖结构和生物功能。这些接触性质的异常会导致血管系统的许多病变，如癌症转移和肺水肿。虽然我们知道细胞-细胞接触随着体内动态局部环境的变化而不断变化，但我们对细胞对细胞间结合变化的反应知之甚少。目前促进或破坏细胞-细胞接触的体外模型使用药理学或机械方法，这些方法会向细胞内反应引入混淆变量，因此不适合解决细胞-细胞结合和细胞反应之间的因果关系。本研究旨在研究内皮细胞对细胞间接触起始的早期（数秒至数小时）反应。它假设接触之间的初始接触在决定最终导致细胞-细胞连接形成、细胞内信号传导、细胞骨架锚定和重组以及细胞分化的事件序列中起因果作用。要研究的行为是细胞骨架的重排，膜蛋白的重新定位，以及细胞间初始和随后结合时信号通路的激活。这项研究将开发一种基于微型自组装的通用方法，细胞附着在独立的底物上，在特定时间引入物理细胞-细胞接触，而不改变细胞-基质相互作用。细胞间结合开始时细胞内发生的事件的识别将有助于推进对正常和病理血管形成的分子和结构基础的理解，并可能导致开发治疗某些血管疾病的有效疗法。

Cell-cell contacts play an important role in the normal function of endothelial cells. Contacts between cells not only act as a physical barrier that seals the vessel, but also alter the anatomical structure and biological function of these cells. Abnormalities in the nature of these contacts result in many pathologies of the vascular system, such as cancer metastasis and pulmonary edema. While it is known that cell-cell contacts change continually in response to the dynamic local environment in vivo, little is known about the cellular response to these changes in intercellular binding. Current in vitro models that promote or disrupt cell-cell contacts use pharmacologic or mechanical approaches that introduce confounding variables to the intracellular responses, and thus are not suited to address the causal relationship between cell-cell binding and cellular response. The proposed research intends to study the early (seconds to hours) stage response of endothelial cells to initiation of cell-cell contact. It hypothesizes that the initial contact between contacts plays a causal role in determining the sequence of events that ultimately lead to cell-cell junctional formation, intracellular signaling, cytoskeletal anchoring and reorganization, and cell differentiation. The behaviors to be examined are the rearrangement of cytoskeleton, the relocalization of membrane proteins, and the activation of signaling pathways upon the initial and subsequent binding between cells. This research will develop a general methodology based on the self-assembly of microscale, free-standing substrates on which cells are attached, to introduce physical cell-cell contact at specific times and without alteration of cell-matrix interactions. Identification of the events that occur within the cell upon initiation of intercellular binding will help to advance the understanding of the molecular and structural bases of normal and pathologic vessel formation, and may lead to the development of effective therapies to treat certain vascular diseases.