Smooth Muscle Mechanisms in Dynamic Airway Properties

项目摘要 气道平滑肌(ASM)是一种多功能组织，具有复杂的生理特性。此外 由于ASM在调节呼吸道狭窄方面的众所周知的作用，ASM产生和分泌免疫调节作用 化合物，使细胞外基质(ECM)蛋白增殖，并在 收缩和合成状态，对来自其局部环境的多个线索作出反应。在肺里， ASM细胞的细胞外环境可能受到生理和病理生理条件的调节 可以改变呼吸道组织结构、细胞外基质成分和施加在呼吸道上的机械力，所有这些 其中可引发ASM对细胞外刺激的表型和生理反应的改变。这个 ASM细胞表型和生理特性受调控的机制 细胞外条件对于理解ASM在正常和病理生理状态下的功能至关重要 条件。在组织内连接细胞和细胞外基质的黏附连接由大的 称为粘附体的多蛋白复合体。粘附体在细胞中发挥着关键功能，远远超出了 它们的结构作用：虽然它们在细胞和其基质环境之间提供机械耦合，但它们 也使细胞能够感知并对周围环境属性的变化做出反应。我们的研究 已经表明，收缩和炎症刺激会触发膜粘附性复合体的组装 在ASM组织中。这些研究导致了一个新的和详细的假说，分子机制 在ASM中对生理刺激作出反应的粘性组装。我们认为，这一过程是一个基本的 从不同的刺激中传递信号所必需的过程。然而，分子 调节粘性组件以将信号调制到不同下游效应器的机制 人们还不了解这些途径。我们假设S100蛋白家族的成员S100A4和α- 和β-Parvins，三聚体整合素连接的激酶(ILK)-Pinch-Parvin复合体的组成部分，是关键 在粘性组装和信号差异激活中发挥关键作用的中间体 ASM中的细胞外刺激途径。我们还建议S100A4在细胞外作用于ASM组织，以 促进炎症和合成表型。拟议的研究将使用ASM组织和新鲜的 分离分化的ASM细胞以达到三个特定的目的：1)确定S100A4在 调节ASM对收缩刺激的反应。2)确定S100A4作为调节因子的作用 并使用小鼠模型评估其在呼吸道炎症中的作用。3)确定分子 ASM表型对环境和炎症刺激反应的调节机制。 这些研究将为ASM信号转导的分子机制提供新的见解 可能与其他细胞和组织广泛相关，这可以为治疗提供新的靶点 对导致呼吸道高反应性或炎症的病理生理状况的干预。

Project Summary Airway smooth muscle (ASM) is a multifunctional tissue with complex physiologic properties. In addition to its well-known role in regulating airway narrowing, ASM produces and secretes immunomodulatory compounds, makes extracellular matrix (ECM) proteins, proliferates, and actively transitions between a contractile and a synthetic state in response to multiple cues from its local environment. In the lung, the extracellular environment of ASM cells may be modulated by both physiologic and pathophysiologic conditions that can alter airway tissue structure, ECM composition, and the mechanical forces imposed on the airways, all of which can trigger changes in the phenotype and physiologic responses of ASM to extracellular stimuli. The mechanisms by which the phenotypic and physiologic properties of ASM cells are modulated in response to extracellular conditions are critical for understanding the function of ASM under normal and pathophysiologic conditions. The adhesion junctions that connect cells to the ECM within tissues are composed of large multiprotein complexes termed adhesomes. Adhesomes play critical functions in cells that extend far beyond their structural role: while they provide mechanical coupling between cells and their matrix environment, they also enable cells to sense and respond to changes in the properties of their surrounding milieu. Our studies have shown that contractile and inflammatory stimuli trigger the assembly of membrane adhesome complexes in ASM tissues. These studies have led to a novel and detailed hypothesis for the molecular mechanisms for adhesome assembly in ASM in response to physiologic stimuli. We propose that this process is a fundamental process that is essential for the transduction of signals from diverse stimuli. However, the molecular mechanisms by which adhesome assembly is regulated to modulate signals to different downstream effector pathways are not understood. We hypothesize that S100A4, a member of the S100 protein family, and the α- and β-parvins, components of the trimeric integrin-linked kinase (ILK)-PINCH-parvin complex, are key intermediaries that play critical roles in adhesome assembly and in the differential activation of signaling pathways by extracellular stimuli in ASM. We also propose that S100A4 acts extracellularly on ASM tissues to promote inflammation and the synthetic phenotype. The proposed studies will employ ASM tissues and freshly dissociated differentiated ASM cells to address three Specific Aims: 1) Determine the role of S100A4 in regulating the response of ASM to contractile stimuli. 2) Determine the role of S100A4 as a mediator of inflammation and evaluate its role in airway inflammation using a murine model. 3) Determine the molecular mechanisms for the modulation of ASM phenotype in response to environmental and inflammatory stimuli. These studies will provide new insights into the molecular mechanisms of signal transduction in ASM that are likely to be broadly relevant to other cells and tissues, and that can provide new targets for therapeutic intervention in pathophysiologic conditions that result in airway hyperresponsiveness or inflammation.