Pathophysiology of PPARgamma in the lung

描述（由申请人提供）：过氧化物酶体增殖物激活受体γ（PPAR）是包括肺在内的各种组织系统中的抗炎分子。它在肺中的功能作用还不清楚。这项工作的长期目标将确定肺发病机制中的分子途径。提出的研究的中心假设是，PPAR是通过基质金属蛋白酶-12（MMP-12）的分子控制的肺部炎症介质，并且这种控制来自溶酶体中由溶酶体酸性脂肪酶（LAL）产生的脂肪酸配体。这已经得到我们先前的研究的支持，即在溶酶体酸性脂肪酶缺陷小鼠（lal-/-）中阻断其配体合成引起肺部炎症、肺气肿、不需要的上皮细胞生长和异常基因表达。用PPAR（配体9-HODE和格列酮）治疗显著减弱了肺炎症和异常基因表达。在体外瞬时转染试验中，配体和PPAR α负调节MMP-12启动子活性。PPAR 0蛋白主要在肺中的支气管肺泡巨噬细胞、Clara细胞和肺泡II型上皮细胞中检测到。因此，中心假设将在我们的两个新的转基因模型中进行测试，其中内源性PPAR（）通过在多西环素诱导的转基因小鼠系统中肺泡II型上皮细胞或支气管肺泡巨噬细胞中过表达其显性负性形式（dnPPAR（））而失活。转基因模型的初步评估显示炎性细胞流入肺和肺气肿，其中dnPPAR在CCSP启动子的控制下过表达2个月。此外，MMP 12的表达水平在dnPPAR（转基因小鼠）中增加了55倍。dnPPAR的长期致病作用（过度表达）尚未确定。设计了三个具体目标来检验中心假设：具体目标1：确定dnPPAR的发病机制（在呼吸道上皮细胞中）;具体目标2：确定dnPPAR的发病机制（在巨噬细胞中）;具体目标3：确定肺上皮细胞中MMP 12调节的分子机制。总之，这些研究将显著增强我们对PPAR（在肺中，特别是在肺部炎症和组织重塑中）的病理生理学功能的理解，并阐明介导lal-/-小鼠肺中表型的MMP 12中的基因调控的分子机制。这些研究的结果将为设计对抗肺部炎症和肺气肿的新策略提供证据。项目叙述：本研究计划的目的是了解过氧化物酶体增殖物激活受体γ（PPAR）作为肺部抗炎效应物的关键作用。我们正在使用最先进的技术来创建转基因小鼠，这些小鼠在肺细胞（肺泡II型上皮细胞或支气管肺泡巨噬细胞）中具有细胞特异性和时间调节的显性阴性形式的PPAR（（dnPPAR（））表达，并表征其肺部炎症、重塑和肺气肿表型。此外，拟开展的研究将阐明通过基质金属蛋白酶-12（MMP-12）基因的转录调控使PPAR失活以及重塑和肺气肿表型的分子联系。总之，这些研究将显著增强我们对PPAR（在肺中，特别是在肺部炎症和组织重塑中）的病理生理功能的理解。这些研究将提供新的方法来设计策略和发现药物来对抗肺气肿和COPD。

DESCRIPTION (provided by applicant): Peroxisome proliferator-activated receptor gamma (PPAR() is an anti-inflammatory molecule in various tissue systems including the lung. Its functional role in the lung is not well understood. The long-term goal of this work will determine PPAR( molecular pathways in lung pathogenesis. The central hypothesis for the proposed studies is that PPAR( is a mediator of pulmonary inflammation via the molecular control of matrix metalloproteinase-12 (MMP-12) and that this control derives from fatty acid ligands, generated in the lysosomes by lysosomal acid lipase (LAL). This has been supported by our previous study that blockage of its ligand synthesis in lysosomal acid lipase deficient mice (lal-/-) caused pulmonary inflammation, emphysema, unwanted epithelial cell growth and aberrant gene expression. Treatment with PPAR( ligands 9-HODE and Ciglitazone significantly attenuated lal-/- pulmonary inflammation and aberrant gene expression. The ligands and PPAR( negatively regulate MMP-12 promoter activity in in vitro transient transfection assays. The PPAR( protein is primarily detected in broncho-alveolar macrophages, Clara cells and alveolar type II epithelial cells in the lung. Thus, the central hypothesis will be tested in our two new transgenic models, in which endogenous PPAR( is inactivated by over-expression of its dominant negative form (dnPPAR() in alveolar type II epithelial cells or bronchoalveolar macrophages in doxycycline-inducible transgenic mouse system. Preliminary assessment of a transgenic model, in which dnPPAR( was over- expressed for 2 months under the control of the CCSP promoter, showed inflammatory cell influx into the lung and emphysema. In addition, the expression level of MMP12 increased 55-fold in the dnPPAR( transgenic mice. The long-term pathogenic effect of dnPPAR( over-expression has not been determined. Three specific aims are designed to test the central hypothesis: Specific Aim 1: Determine pathogenesis of dnPPAR( in respiratory epithelial cells; Specific Aim 2: Determine pathogenesis of dnPPAR( in macrophages; Specific Aim 3: Determine molecular mechanism of MMP12 regulation in lung epithelial cells. Together, these studies will significantly enhance our knowledge for understanding the pathophysiological function of PPAR( in the lung, especially in pulmonary inflammation and tissue remodeling, and elucidate the molecular mechanism of gene regulation in MMP12 that mediates the phenotype in the lung of lal-/- mice. The outcomes of these studies will provide evidence to design new strategies to combat pulmonary inflammation and emphysema. PROJECT NARRATIVE: The objectives of this research proposal are to understand the critical role of peroxisome proliferator- activated receptor gamma (PPAR() as anti-inflammatory effector in the lung. We are using the state-of-art techniques to create transgenic mice that have cell specific and temporal regulated expression of dominant negative form of PPAR( (dnPPAR() in pulmonary cells (alveolar type II epithelial cells or bronchio-alveolar macrophages) and characterizing their pulmonary inflammation, remodeling, and emphysema phenotype. In addition, the proposed studies will elucidate the molecular linker of inactivation of PPAR( and the remodeling and emphysema phenotype through transcriptional regulation of matrix metallproteinase-12 (MMP-12) gene. Together, these studies will significantly enhance our knowledge for understanding the pathophysiological function of PPAR( in the lung, especially in pulmonary inflammation and tissue remodeling. These studies will provide new approaches to design strategies and discover drugs to combat emphysema and COPD.