Organic dust epithelial PKC activation & airway disease

有机粉尘上皮PKC激活

• 批准号: 7478045
• 负责人: DEBRA J ROMBERGER
• 金额: $ 34万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7478045
• 关键词: Organic; dust; epithelial; PKC; activation

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.

描述（由申请人提供）：接触有机粉尘是导致气道疾病的一个原因，包括慢性阻塞性肺病（COPD）。多达 20% 的 COPD 病例归因于职业暴露。在农村地区，粉尘暴露的一个重要来源是生猪圈养舍。接触猪舍的人会出现气道炎症，慢性阻塞性肺病的发病率也会增加。尽管猪舍灰尘中存在许多可引起炎症的物质（包括内毒素），但导致慢性阻塞性肺病的实际机制尚不清楚。了解猪舍粉尘引起的气道疾病的机制对于制定有针对性的治疗和预防策略具有重要意义。上皮细胞对吸入的药物做出反应，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，猪舍灰尘提取物 (HDE) 增强人气道上皮蛋白激酶 C (PKC) 激活，导致 IL-8 和 IL-6 释放并增加 ICAM-1 表达，在体外介导炎症细胞粘附到气道上皮。通过对小鼠进行鼻内暴露于 HDE，我们观察到体内气道上皮 PKC 激活和炎症反应增加。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 处理使 LPA 失活，从而抑制 HDE 刺激的 IL-6 和 IL-8 释放。猪舍灰尘诱导的 LPA 在引导气道炎症中的作用尚不清楚。本提案的目的是确定猪舍灰尘激活上皮细胞 PKC 的机制以及 PKC 在与监禁设施工作人员发生的慢性支气管炎相关的气道炎症中的作用，并确定与猪舍灰尘相关的 LPA（一种重要的脂质介质）在调节灰尘对 PKC 和炎症反应的影响中的作用。我们将通过以下具体目标来阐述我们的假设：1) 确定 HDE 中激活上皮细胞 PKC 的因子的生化性质和特定身份，并识别 HDE 和这些因子激活的特定 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 HDE 体外增强上皮细胞 PKC 介导体外炎症细胞募集和粘附到气道上皮的机制。 4) 利用暴露动物模型确定 HDE 如何在体内调节气道上皮 PKC 激活和炎症反应，包括测试 LPA 的潜在作用。