Actin-myosin contractility promotes the development of chronic bronchitis

项目摘要 慢性阻塞性肺疾病（COPD）是美国第三大死亡原因，有很大的子集 慢性支气管炎的病人。在这个时候，我们没有药物治疗慢性支气管炎（CB）。在 美国，香烟烟雾（CS）是主要的侮辱，导致CB;然而，我们不明白CS如何改变 上皮促进粘液的发育。在我们的工作中，我们发现慢性CS会导致 上皮细胞，以影响其形状并减少细胞-细胞粘附蛋白如E-钙粘蛋白， 防止在相邻电池之间形成接触。在本提案中，我们将解读 肌动蛋白-肌球蛋白II收缩性改变。我们认为，细胞收缩性的增加降低了细胞的极性。 上皮细胞促进细胞信号传导事件，包括上皮生长因子受体的激活 （EGFR）。EGFR的激活，反过来，导致与慢性支气管炎相关的变化，如增加 Muc 5AC生产。我们建议研究药物干预来改变肌动蛋白-肌球蛋白收缩性， 研究其对E-cadherin、细胞-细胞粘附、细胞极性与EGFR活化和Muc 5AC产生的影响。在 目的1，我们将确定CS是否会导致肌球蛋白II驱动的肌动蛋白-肌球蛋白收缩性增加， 膜E-钙粘蛋白和破坏细胞-细胞粘附。具体来说，我们将剖析 CS增加肌动蛋白-肌球蛋白收缩性，并确定操纵这种增加是否会改变E- 钙粘蛋白水平和细胞-细胞粘附。在目标2中，我们将确定CS诱导的肌动蛋白-肌球蛋白II增加是否 收缩性导致上皮细胞增加异常EGFR活化。具体来说，我们将确定， 增加的收缩性改变了上皮的极性，以促进EGF受体-配体相互作用， 顶膜或基底外侧膜以增加EGFR活化。在目标3中，我们将确定，在小鼠中， 模型，降低肌动蛋白-肌球蛋白收缩性将逆转EGFR激活和Muc 5AC的产生。 慢性CS后的上皮。我们将确定在体内抑制肌动蛋白-肌球蛋白II的收缩性是否可以预防或 消除慢性CS后小鼠中明显的CS诱导的Muc 5AC和粘蛋白产生的增加 exposure.我们已经发现，E-钙粘蛋白敲低促进小鼠EGFR活化。使用我们新的 建立了敲除小鼠肺上皮中E-钙粘蛋白的模型，我们将评估肌动蛋白-肌球蛋白是否 收缩性是E-钙粘蛋白减少的上游，导致EGFR活化和Muc 5AC增加。这是一 一个早期研究者的五年资助计划。

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.