Transduction of the environment in airway epithelium

描述（由申请人提供）：机械环境深刻影响肺的结构和功能，从发育中肺的分支形态发生和细胞分化到成熟器官的生长、损伤和重塑。细胞感知和响应其机械环境的潜在分子机制仍然难以捉摸。最近获得的证据表明，分隔气道上皮细胞的细胞间隙在生理负荷下是高度可变形的。这些细胞间隙是涉及表皮生长因子受体（EGFR）及其配体的假定自分泌信号环的位点。在体外和原位，施加于气道上皮细胞的生理水平的机械应力通过EGFR途径触发信号传导。这些观察结果的整合导致以下中心假设：机械应力可以通过稳态活动的自分泌EGFR环在动态调节的细胞间隙中进行转导。将使用原代人气道上皮培养物在以下三个特定目的中检验该假设：（1）建立上皮细胞间隙中自分泌信号环的分子组分和组成功能;（2）确定细胞间隙对生理相关负荷条件的动态生物物理响应;以及（3）使用生物化学和计算工具来检验中心假设，然后探索其在调节mucSAC表达中的生物学作用，mucSAC是在各种气道疾病中上调的粘液分泌表型的标志物。由此产生的见解可以为细胞外空间中发生的机械转导建立一个新的和意想不到的范例，并改变我们对机械力如何促进健康和疾病中气道生物学的看法。肺在正常（例如呼吸）和疾病（例如哮喘）状况期间经历一系列机械力，从而影响肺结构和功能。拟议中的研究将探索排列在气道上的细胞如何感知和响应其机械环境的变化。这些研究将为理解和调节肺的机械反应提供一个框架。

DESCRIPTION (provided by applicant): The mechanical environment profoundly influences the structure and function of the lung, from branching morphogenesis and cellular differentiation in the developing lung, to growth, injury, and remodeling of the mature organ. The underlying molecular mechanisms by which cells sense and respond to their mechanical environment remain elusive. Recently obtained evidence demonstrates that the intercellular spaces separating airway epithelial cells are highly deformable under physiological loads. These intercellular spaces are the site of putative autocrine signaling loops involving the epidermal growth factor receptor (EGFR) and its ligands. Physiological levels of mechanical stress applied to airway epithelial cells, both in vitro and in situ, trigger signaling through the EGFR pathway. Integration of these observations leads to the following central hypothesis: mechanical stress can be transduced through the steady-state activity of an autocrine EGFR loop operating in a dynamically regulated intercellular space. This hypothesis will be tested in the following three specific aims using primary human airway epithelial cultures: (1) establish the molecular components and constitutive functionality of the autocrine signaling loop in the epithelial intercellular space; (2) define the dynamic biophysical response of the intercellular space to physiologically relevant loading conditions; and (3) use biochemical and computational tools to test the central hypothesis, then explore its biological role in modulating the expression of mucSAC, a marker of the mucus secretory phenotype upregulated in various airway disorders. The resulting insights could establish a new and unanticipated paradigm for mechanotransduction occurring in the extracellular space, and change our view of how mechanical forces contribute to the biology of the airways in health and disease. The lung experiences a range of mechanical forces during normal (e.g. breathing) and disease (e.g. asthma) conditions, influencing lung structure and function. The proposed studies will explore how the cells that line the airways sense and respond to changes in their mechanical environment. These studies will provide a framework for understanding and modulating mechanical responses in the lung.