Regulation of Airway Goblet Cell Mucin Secretion

描述：阻塞性肺疾病(OPD)、囊性纤维化、慢性支气管炎、支气管扩张、肺气肿和哮喘是炎症性疾病，具有非常不同的炎症细胞类型、细胞因子反应等；呼吸道表面杯状细胞和粘膜下粘液细胞的粘蛋白高分泌是一个独特的共同特征。从概念上讲，粘蛋白高分泌可能是由炎症驱动的杯状细胞过度/增殖和/或粘蛋白分泌率增加所致。尽管OPD的最佳长期治疗可能针对炎症的个别原因，但值得注意的是，通常情况下，OPD患者的急性缓解可以通过选择性抑制粘蛋白分泌来实现。可能更重要的是，这种抑制剂将有助于打开粘液堵塞的呼吸道，从而能够有效地、以吸入为基础的疾病治疗。因此，我们的长期目标是研究调节呼吸道杯状细胞中粘蛋白颗粒胞吐的分子机制，以确定选择性药物治疗的分子靶点。众所周知，杯状细胞的粘蛋白分泌是由细胞外的ATP和UTP通过P2Y2受体(P2Y2-R)调节的，而随后的分泌反应是由磷脂酶C途径通过蛋白激酶C和钙介导的。然而，我们对参与杯状细胞调控的信号通路的了解还不完整。例如，毒扁豆碱类激动剂的作用存在很大争议，目前还没有关于调节呼吸道杯状细胞基础粘蛋白分泌的机制和途径的数据，以及通过酪氨酸激酶途径通过受体传递信号的药物的影响尚不清楚，尽管其中许多药物确实对呼吸道上皮有化生作用。在分子水平上，除了细胞内信使的身份外，我们对调控胞吐作用的效应器知之甚少。因此，我们提出了一种广泛的方法，利用原代培养的人支气管上皮细胞、人肺上皮细胞和经过遗传操作的转化为杯状细胞的小鼠，以及SPOC1杯状细胞，以进一步描述气道杯状细胞黏蛋白颗粒胞吐的细胞内分子调控，并将我们对调控杯状细胞功能的信号通路的知识扩展到涉及基础粘蛋白分泌、I型受体和参与以及机械剪切效应的新领域。

DESCRIPTION: The obstructive pulmonary diseases (OPD), cystic fibrosis, chronic bronchitis, bronchiectasis, emphysema, and asthma, are inflammatory diseases with very different inflammatory cell profiles, cytokine responses, etc; mucin hypersecretion from airway surface goblet cells and submucosal mucous cells represents a singular, shared characteristic. Conceptually, mucin hypersecretion may result from inflammation-driven goblet cell meta/hyperplasia and/or elevated rates of mucin secretion. Although the best long-term treatment for OPDs will likely target the individual causes of inflammation, it is notable that acute relief to OPD patients, generally, could be achieved by selectively inhibiting mucin secretion. Possibly more important, such an inhibitor would help to open mucus-clogged airways to enable efficient, inhalation-based treatment of the underlying disease. Hence, our long-range goal is to study the molecular mechanisms by which mucin granule exocytosis in airway goblet cells is regulated, to identify molecular targets for selective drug therapies. It is well known that goblet cell mucin secretion is regulated by extracellular ATP and UTP acting through the P2Y2 receptor (P2Y2-R), and that the subsequent secretory response is mediated by the phospholipase C pathway through PKC and Ca2+. Yet, our knowledge of the signaling pathways involved in goblet cell regulation is incomplete. For instance, the effects of muscarinic agonists are highly controversial, there are no data relevant to the mechanisms and pathways underlying the regulation of basal mucin secretion from airway goblet cells, and the effects of agents signaling through receptors acting via tyrosine kinase pathways are uknown, though many of them do have metaplastic effects on the airways epithelium. At the molecular level, we know very little of the effectors regulating exocytosis beyond the identities of the intracellular messengers. Hence, we propose a broadly based approach using the primary cultures of human bronchial epithelial cells, airways epithelium from human lungs and genetically manipulated mice rendered metaplastic for goblet cells, and SPOC1 goblet cells to further delineate the intracellular molecular regulation of mucin granule exocytosis from airway goblet cells, and to extend our knowledge of the signaling pathways regulating goblet cell function into new areas involving basal mucin secretion, type I receptor and involvement, and mechanical shear effects.