Pathophysiology of Mucus Hypersecretion in Asthma

描述：(申请人提供)：粘液高分泌是一种突出的 是许多肺部疾病的特征。在正常情况下，由呼吸道上皮分泌的粘液提供了一种粘弹性屏障，作为主要的 对病原体和有害刺激物的防御机制。人类的肺 哮喘和哮喘动物模型富含含粘蛋白的高脚杯 细胞和粘液堵塞，表明粘液化生是 哮喘表型。化生导致呼吸道的转化 上皮从主要不分泌的表型转变为特殊的粘液 分泌表型。因此，细胞必须组装所需的分子机械。 用于分泌性小泡对接和融合。然而，在呼吸道上皮中， 人们对分泌机制的组成和功能知之甚少。 在来自人类和低等生物的各种其他细胞类型中，Munc18 蛋白质家族是胞吐作用的重要调节者，服务于两种阳性 和负功能。Munc18的基本积极作用得到了证明 在小鼠中，小鼠Munc18-1(神经元特异性)的敲除 同型)和果蝇Munc18直系ROP突变导致完全性 神经分泌衰竭和瘫痪。然而，ROP的过度表达， 导致剂量依赖的神经分泌抑制，从而表明 ROP在果蝇中的负作用，进而在哺乳动物中，Munc18也是负作用。 Munc18蛋白在包括肥大在内的非神经性组织中也有表达。 它们调节分泌的细胞和胰岛β细胞。基于这些 ，我们建议通过以下方法来研究Munc18的表达和功能 呼吸道上皮细胞及Munc18过表达对黏液的影响 NCI-H292细胞的体外分泌和小鼠模型的体内分泌 肺部发炎。迪基？S博士的实验室此前已经证明 该功能性Munc18-2在大鼠肥大细胞中表达。建议的项目 Here利用他实验室中的专业知识和试剂进行应用 哮喘的一个重要问题。

DESCRIPTION: (provided by applicant):Mucus hypersecretion is a prominent feature of many pulmonary diseases. Under normal conditions the mucus secretedby the airway epithelium provides a viscoelastic barrier that acts as a primary defense mechanism against pathogens and noxious irritants. The lungs of humans with asthma and of animal models of asthma are rich in mucin-containing goblet cells and mucus plugs, indicating that mucus metaplasia is a feature of the asthma phenotype. Metaplasia results in the transformation of the airway epithelium from a largely non-secretory phenotype into a specialized mucus secreting phenotype. Thus, cells must assemble the molecular machinery required for secretory vesicle docking and fusion. In the airway epithelium, however, the composition and function of the secretory machinery is poorly understood. In various other cell types from humans and from lower organisms, the MUNC18 family of proteins are important regulators of exocytosis serving both positive and negative functions. The essential positive role for MUNC18 is demonstrated in mice, where the knockout of the murine MUNC18-1 (the neuron specific isoform) and the mutation of Drosophila MUNC18 ortholog ROP result in complete failures of neurosecretion and paralysis. Over-expression of ROP, however, causes a dose dependent inhibition of neurosecretion, thereby indicating a negative role for ROP in Drosophila, and by extension, MUNC18 in mammals. MUNC18 proteins are also expressed in non-neuronal tissues, including mast cells and pancreatic beta cells where they regulate secretion. Based on these observations, we propose to study the expression and function of MUNC18 by airway epithelial cells and the effects of MUNC18 over expression on mucus secretion both in vitro in NCI-H292 cells and in vivo in mouse models of pulmonary inflammation. Dr. Dickey?s laboratory has previously demonstrated that functional MUNC18-2 is expressed in rat mast cells. The project proposed here utilizes expertise and reagents available in his laboratory applies them to an important problem in asthma.