Actin-myosin contractility promotes the development of chronic bronchitis

项目总结 慢性阻塞性肺疾病(COPD)是美国第三大死因，占很大比例 表现为慢性支气管炎的患者。目前我们还没有治愈慢性支气管炎(CB)的药物。在……里面 在美国，吸烟(CS)是主要的侮辱，导致CB；然而，我们不知道CS如何改变 上皮细胞促进粘液的发育。在我们的工作中，我们发现慢性CS会导致关节僵硬 为了影响上皮细胞的形态，减少细胞与细胞间的黏附蛋白，如E-钙粘蛋白，以 防止相邻电池之间形成接触。在这项提案中，我们将破译 改变肌动蛋白-肌球蛋白II的收缩能力。我们认为，细胞收缩能力的增加降低了细胞的极性 上皮细胞促进细胞信号事件，包括激活上皮生长因子受体 (EGFR)。EGFR的激活反过来会导致与慢性支气管炎相关的变化，例如 MUC5AC生产。我们建议研究改变肌动蛋白-肌球蛋白收缩能力的药物干预措施 研究其对E-钙粘附素、细胞间黏附、细胞极性、EGFR活化和MUC5AC产生的影响。在……里面 目的1，我们将确定CS是否导致肌球蛋白II驱动的肌球蛋白收缩能力降低 膜E-钙粘附素和破坏细胞与细胞间的黏附。具体地说，我们将剖析分子机制 通过CS增加肌动蛋白-肌球蛋白的收缩能力，并确定操纵这种增加是否会改变E- 钙粘附素水平与细胞间黏附。在目标2中，我们将确定CS是否诱导肌动蛋白-肌球蛋白II增加 收缩导致上皮细胞增加异常的EGFR激活。具体来说，我们将确定是否 收缩能力的增强改变了上皮的极性，促进了EGF受体与配体的相互作用 顶端或基底侧膜以增加EGFR的活性。在目标3中，我们将确定在一只小鼠身上 模型中，降低肌球蛋白的收缩能力将逆转EGFR的激活和MUC5AC的产生 慢性CS后的上皮细胞。我们将确定在体内抑制肌动蛋白-肌球蛋白II的收缩能力是否会阻止或 消除CS诱导的小鼠慢性CS后MUC5AC和粘蛋白产生的明显增加 曝光。我们已经发现E-钙粘素基因敲除促进了小鼠EGFR的激活。使用我们的新功能 建立了敲除小鼠肺上皮细胞E-钙粘蛋白的模型，我们将评估肌动蛋白-肌球蛋白是否 收缩能力的上游是E-钙粘蛋白的减少，导致EGFR激活和MUC5AC增加。这是一个 一位早期调查员提出的为期五年的拨款建议。

PROJECT SUMMARY Chronic Obstructive Pulmonary Disease (COPD) is the 3rd leading cause of death in the US with a large subset of patients exhibiting chronic bronchitis. At this time we have no medications to cure chronic bronchitis (CB). In the U.S., cigarette smoke (CS) is the primary insult, leading to CB; yet, we do not understand how CS alters the epithelium to promote the development of mucus. In our work, we found that chronic CS causes stiffening of the epithelial cell in order to impact on its shape and decrease cell-cell adhesion proteins such as E-cadherin, to prevent the formation of contacts between neighboring cells. In this proposal, we will decipher the effects of altered actin-myosin II contractility. We propose that this increase in cell contractility decreases the polarity of the epithelial cell to promote cell-signaling events, including the activation of the epithelial growth factor receptor (EGFR). EGFR activation, in turn, leads to changes associated with chronic bronchitis, such as the increase in Muc5AC production. We propose to study pharmacologic interventions to alter actin-myosin contractility to study its effects on E-cadherin, cell-cell adhesion, cell polarity with EGFR activation and Muc5AC production. In Aim 1, we will determine if CS causes myosin II-driven increases in actin-myosin contractility to decrease membrane E-cadherin and disrupting cell-cell adhesion. Specifically, we will dissect the molecular mechanisms by which CS increases actin-myosin contractility, and determine if manipulating this increase will alter E- cadherin levels and cell-cell adhesion. In Aim 2, we will determine if CS-induced increased actin-myosin II contractility causes the epithelial cell to increase aberrant EGFR activation. Specifically, we will determine if increased contractility alters the polarity of the epithelium to promote EGF receptor-ligand interaction on either the apical or basolateral membrane to increase EGFR activation. In Aim 3, we will determine if, in a mouse model, decreasing the actin-myosin contractility will reverse EGFR activation and Muc5AC production by the epithelium after chronic CS. We will determine if inhibiting actin-myosin II contractility in vivo prevents or abrogates the CS-induced increase in Muc5AC and mucin production evident in mice after chronic CS exposure. We have found that E-cadherin knockdown promotes EGFR activation in mice. Using our newly established model to knockdown E-cadherin in the mouse lung epithelium, we will assess if actin-myosin contractility is upstream of decreases in E-cadherin to cause EGFR activation and increased Muc5AC. This is a five year grant proposal from an Early Stage Investigator.