FIZZ1 Expression and Function in Pulmonary Fibrosis

项目III：肺纤维化涉及多种细胞类型之间通过复杂的介质系统的复杂相互作用。进行性纤维化疾病，如特发性肺纤维化（常见的间质性肺炎）基本上仍然是一种无法治疗的疾病，具有致命的结局。使用微阵列方法的最新进展有助于识别以前未被怀疑的似乎在纤维化中起重要作用的分子。使用这种方法，初步数据揭示了最近发现的称为FIZZ 1（在炎症区1中发现）的分子在博来霉素诱导的肺纤维化的啮齿动物模型中的诱导。这是使用10 k大鼠基因芯片的最高度诱导的分子，其通过RT-PCR确认为相对于对照肺诱导>30倍。FIZZ 1，也被称为抵抗素样分子α（RESISTIN-LIKE MOLECULE alpha，ARM-alpha），也在过敏性气道疾病的炎症气道上皮中高度表达，但其功能尚不清楚。博来霉素模型中的初步证据证实了表达主要定位于气道和肺泡上皮中，这通过分离的II型肺细胞的分析得到证实。然而，肺成纤维细胞似乎不表达FIZZ 1。这种表达FIZZ 1的II型肺细胞与成纤维细胞的共培养诱导它们分化为肌成纤维细胞。基于这些初步数据，本项目的中心假设是肺泡上皮细胞诱导FIZZ 1表达在肺纤维化中起作用。 通过诱导肌成纤维细胞分化来研究肺纤维化的发病机制。为了验证这一假设，提出了四个具体目标。首先，将在博莱霉素模型中确定肺FIZZ 1表达改变的动力学，并尝试使用原位杂交和免疫组织化学的组合进行表达的细胞定位。将在分离和纯化的肺细胞中进行细胞表达的体外确认。其次，为了分析其维斯维斯纤维化的生物活性，将在表达FIZZ 1的II型肺细胞和不表达肺成纤维细胞之间进行共培养研究，以观察肺泡上皮和成纤维细胞之间的串扰是否由FIZZ 1介导。确认任何 活性将使用FIZZ 1表达质粒进行，用于使用肺成纤维细胞的转染研究，并用于产生重组FIZZ 1。第三，将分析II型细胞中FIZZ 1表达的调节和相关的信号通路。最后，将产生FIZZ 1敲除小鼠，并使用siRNA方法来确认其体外活性的体内相关性。

Project III: Pulmonary fibrosis involves complex interactions between multiple cell types via an intricate system of mediators. Progressive fibrotic diseases such as idiopathic pulmonary fibrosis (usual interstitial pneumonitis) remain essentially an untreatable disease with a fatal outcome. Recent progress using microarray approaches have helped to identify previously unsuspected molecules that appear to play significant roles in fibrosis. Using such an approach preliminary data revealed induction of a recently discovered molecule termed FIZZ1 (Found in Inflammatory Zone 1) in a rodent model of bleomycin-induced pulmonary fibrosis. This was the most highly induced molecule using a 10k rat gene chip, which was confirmed by RT-PCR to be >30-fold induced over control lung. FIZZ1, also known as resistin-like molecule alpha (RELM-alpha) is also highly expressed in inflamed airway epithelium in allergic airway disease, but its function remains unclear. Preliminary evidence in the bleomycin model confirms localization of expression mainly to be in airway and alveolar epithelium, which was confirmed by analysis of isolated type II pneumocytes. Lung fibroblasts however appear not to express FIZZ1. Co-culture of such FIZZ1 expressing type II pneumocytes with fibroblasts induced their differentiation to myofibroblasts. Based on these preliminary data, the central hypothesis of this project is that induction of FIZZ1 expression by alveolar epithelial cells plays a role in the pathogenesis of pulmonary fibrosis by inducing myofibroblast differentiation. To test this hypothesis four Specific Aims are proposed. First, the kinetics of alteration in lung FIZZ1 expression will be determined in the bleomycin model, and the cellular localization of expression attempted using a combination of in situ hybridization and immunohistochemistry. Confirmation of cellular expression will be undertaken in vitro in isolated and purified lung cells. Second, to analyze its biological activity vis-&-vis fibrosis, co-culture studies will be undertaken between FIZZ1 expressing type II pneumocytes and non-expressing lung fibroblasts to see if crosstalk between the alveolar epithelium and the fibroblast is mediated by FIZZ1. Confirmation of any activity will be undertaken using a FIZZ1 expressing plasmid for transfection studies using lung fibroblasts, and for the production of recombinant FIZZ1. Third, regulation of FIZZ1 expression in type II cells and associated signaling pathways will be analyzed. Finally, FIZZ1 knockout mice will be generated, and siRNA approaches used to confirm the in vivo relevance of its in vitro activity.