PPAR gamma Signaling and Lung Fibroblast Transdifferentiation

描述（由申请人提供）：异常损伤/修复，肺泡截断，是“新型支气管肺发育不良（BPD）”的主要组织病理学标志。我们最近提出，破坏正常的稳态上皮-间质通讯，以及随之而来的肺泡间质成纤维细胞（AIF）向肌成纤维细胞（MYF）的转分化，是其病理生物学中的关键事件。参与这一过程的具体分子机制尚未完全确定。本提案的目的是通过体内和体外模型确定BPD中涉及的特定分子机制，特别是过氧化物酶体增殖物激活受体（PPAR）信号在高氧诱导的大鼠肺aif向myf转分化中的作用，并确定一种新的分子预防和治疗方法的有效性。在Specific Aim 1中，我们将使用激光捕获显微解剖、形态测定学、免疫组织化学、Real - Time-PCR、Northern和Western分析，在活体新生大鼠模型中确定PPAR激动剂如何预防和/或治疗高氧诱导的AIF-to-MYF转分化。在Specific Aim 2中，我们将利用Real Time -PCR、Northern和Western分析、代谢组学、反义和体外转染研究，检测甲状旁腺激素相关蛋白受体、PPAR、C/增强子结合蛋白和脂肪细胞分化相关蛋白的mRNA表达，并结合相应蛋白的差异表达和磷酸化，确定aif向myf转分化的机制。我们还将确定如何通过有效的PPAR配体如罗格列酮和GW7845刺激脂肪生成途径来阻止或逆转aif到myf的转分化。这一建议，除了为BPD的病理生物学提供新的见解外，还具有开辟新的介入策略的巨大潜力，以治疗一般的慢性肺部疾病，特别是BPD。事实上，使用我们建议中采用的功能基因组方法，即诱导脂肪生成转录因子，不仅可以预防，还可以逆转既定的慢性肺部疾病。本研究提出的概念新颖、创新，脱离了氧致肺损伤的传统范式，可能比简单理解氧致肺损伤具有更广泛的意义。

DESCRIPTION (provided by applicant): Abnormal injury/repair, with truncation of alveolarization, is the major histopathological hallmark of "The New Bronchopulmonary Dysplasia (BPD)". We have recently proposed that disrupting normal homeostatic epithelial-mesenchymal communications, and the consequent alveolar interstitial fibroblast (AIF)-to-myofibroblast (MYF) transdifferentiation, are the key events in its pathobiology. The specific molecular mechanisms involved in this process remain incompletely defined. The objective of this proposal is to determine the specific molecular mechanisms involved in BPD, particularly the role of Peroxisome Proliferator Activated Receptor (PPAR) signaling in hyperoxia-induced rat lung AIF-to-MYF transdifferentiation, using both in vivo and in vitro models and to determine the effectiveness of a novel molecular preventive and therapeutic approach. In Specific Aim 1, using Laser Capture Microdissection, Morphometry, Immunohistochemistry, Real Time-PCR, Northern, and Western analyses, we will determine, in an in vivo neonatal rat model, how PPAR agonists prevent and/or treat hyperoxia-induced AIF-to-MYF transdifferentiation. In Specific Aim 2, using Real Time -PCR, Northern and Western analyses, Metabolomics, Antisense, and Transfection in vitro studies, for the mRNA expression of Parathyroid Hormone-related Protein Receptor, PPAR, C/Enhancer Binding Protein, and Adipocyte Differentiation Related Protein, coupled with the differential expression and phosphorylation of the corresponding proteins, we will determine the mechanism involved in AIF-to-MYF transdifferentiation. We will also determine how AIF-to-MYF transdifferentiation can be prevented or reversed by stimulating the lipogenic pathway through potent PPAR ligands such as rosiglitazone and GW7845. This proposal, in addition to providing new insights into the pathobiology of BPD, has enormous potential for opening up novel interventional strategies to tackle chronic lung disease in general, and BPD in particular. In fact, using the functional genomic approach, adopted in our proposal, i.e., inducing lipogenic transcription factors, may not only prevent, but may also reverse established chronic lung disease. The concept put forward in this proposal is novel, innovative, and departs from the traditional paradigm of oxygen-induced lung damage, and may have much wider implications than simply understanding oxygen-induced lung injury.