Organic dust epithelial PKC activation & airway disease

描述（由申请人提供）：接触有机粉尘是导致气道疾病的原因，包括慢性阻塞性肺疾病（COPD）。多达20%的慢性阻塞性肺病病例归因于职业暴露。在农村地区，一个重要的粉尘暴露源发生在养猪场。暴露于猪舍的人有气道炎症和慢性阻塞性肺病的发病率增加。尽管猪舍灰尘中存在许多诱发炎症的物质，包括内毒素，但导致COPD的实际机制尚未明确。了解猪舍粉尘致气道疾病的机制，有助于制定针对性的治疗和预防策略。上皮细胞对吸入的药物作出反应，释放细胞因子，招募和激活炎症细胞，并表达作为受体和配体与其他细胞相互作用的分子。我们观察到猪舍灰提取物（HDE）增强了人气道上皮蛋白激酶C （PKC）的激活，导致IL-8和IL-6的释放，增加了ICAM-1的表达，介导了炎症细胞对气道上皮的粘附。通过在小鼠鼻内暴露于HDE，我们观察到气道上皮PKC激活和体内炎症反应的增加。我们最近观察到上皮细胞暴露于HDE会导致脂质介质溶血磷脂酸（LPA）的增加。用磷脂酶B灭活LPA可抑制hde刺激的IL-6和IL-8释放。猪舍尘埃诱导的LPA在指导气道炎症中的作用尚不清楚。本提案的目的是确定猪舍粉尘激活上皮细胞PKC的机制，以及PKC在禁闭设施工人发生的慢性支气管炎相关气道炎症中的作用，并确定猪舍粉尘相关的LPA（一种重要的脂质介质）在调节粉尘对PKC和炎症反应的影响中的作用。我们将以这些具体目标来解决我们的假设：1)确定HDE中激活上皮细胞PKC的因子的生化性质和特异性身份，并确定HDE和这些因子激活的特异性PKC同工酶。2)确定hde相关溶血磷脂酸（LPA）如何调节hde诱导的上皮细胞PKC活性和IL-8/IL-6释放。3)确定体外HDE增强上皮细胞PKC介导炎性细胞向气道上皮募集和粘附的机制。4)利用暴露动物模型确定HDE如何调节气道上皮PKC激活和体内炎症反应，包括测试LPA的潜在作用。

DESCRIPTION (provided by applicant): Exposure to organic dusts is a cause of airway disease, including chronic obstructive pulmonary disease (COPD). As many as 20% of COPD cases are attributed to occupational exposures. In rural areas, an important source of dust exposure occurs in hog confinement barns. Persons exposed to hog barns have airway inflammation and an increased incidence of COPD. Although many substances are present in hog barn dust that induces inflammation including endotoxins, actual mechanisms leading to COPD are not well defined. Understanding mechanisms of hog barn dust-induced airway disease is relevant in developing both targeted treatment and prevention strategies. Epithelial cells respond to inhaled agents with the release of cytokines that recruit and activate inflammatory cells and expression of molecules that serve as receptors and ligands for interactions with other cells. We observed that hog barn dust extract (HDE) augments human airway epithelial protein kinase C (PKC) activation, resulting in IL-8 and IL-6 release and increased ICAM-1 expression, mediating inflammatory cell adhesion to airway epithelium in vitro. Using an intranasal exposure to HDE in mice, we observed an increase in airway epithelial PKC activation and inflammatory responses in vivo. We recently observed that epithelial cell exposure to HDE results in an increase of the lipid mediator lysophosphatidic acid (LPA). Treatment with phospholipase B to inactivate LPA inhibits HDE-stimulated IL-6 and IL-8 release. The role of LPA induced by hog barn dust in directing airway inflammation is not known. The objective of this proposal is to define mechanisms by which hog barn dust activates epithelial cell PKC and the role of PKC in airway inflammation associated with chronic bronchitis occurring in confinement facility workers and to determine the role of hog barn dust-related LPA, an important lipid mediator, in modulating dust effects on PKC and inflammatory responses. We will address our hypothesis with these specific aims: 1) Determine the biochemical nature and specific identity of factor(s) in HDE that activate epithelial cell PKC and identify the specific PKC isoenzymes activated by HDE and these factors. 2) Establish how HDE-associated lysophosphatidic acid (LPA) modulates HDE-induced epithelial cell PKC activity and IL-8/IL-6 release. 3) Identify mechanisms by which HDE augmentation of epithelial cell PKC In vitro mediates recruitment and adhesion of inflammatory cells to airway epithelium in vitro. 4) Determine how HDE modulates airway epithelial PKC activation and inflammatory responses in vivo utilizing an animal model of exposure, including testing the potential role of LPA.