eIF3a在肺纤维化中的作用及氟非尼酮治疗机制研究

Pathophysiology of pulmonary fibrosis was characterized by over proliferation of fibroblast and over production of extracellular matrix （ECM）. Eukaryotic initiation factor 3 subunit a (eIF3a) is one of the important protein in the initiation of translation. And it was regarded as a promoter of cell proliferation in certain disease (such as lung cancer). It was reported that mimosine was able to down-regulate eIF3a protein level in several kinds of cancer cells, and fluorofenidone (a derivative of mimosine) could inhibit lung collagen synthesis.The present study is designed to investigate the role of eIF3a in pulmonary fibrosis on bleomycin-induced pulmonary fibrosis animal model. Then,lung fibroblast will be treated by TGF-β1 to approach the detail mechanism of eIF3a promoting cell proliferation. We will also observe the anti-fibrosis effects of fluorofenidone in previous animal model, and the effects of fluorofenidone on fibroblast biological behavior (such as proliferation and collagen synthesis). Our work will be helpful to elucidate a novel mechanism of pulmonary fibrosis pathogenesis，and provide evidences for new therapy target for the pulmonary fibrosis treatment.

肺纤维化的病理生理特点主要表现为成纤维细胞过度增殖与细胞外基质（ECM）生成增多，这两种特征分别与成纤维细胞的周期调控以及合成释放胶原直接相关。真核翻译起始因子3（eIF3）为真核翻译起始因子家族成员，其重要地位在于参与启动蛋白翻译起始过程，它在某些增殖性疾病（如肺癌）的发病中起重要作用。含羞草酸具有抑制eIF3a表达的活性，新合成的化合物氟非尼酮（含羞草酸衍生物）具有抑制肺组织胶原合成的作用。本项目拟在博来霉素诱导动物肺纤维化模型研究eIF3a在肺纤维化形成中的主要作用；在大鼠成纤维细胞，应用转化生长因子β1（TGF-β1）诱导细胞增殖，探讨eIF3a促成纤维细胞增殖及机制；在在体动物与培养细胞，研究氟非尼酮抑制肺纤维化与抑制肺成纤维细胞增殖与胶原合成分泌作用及机制。本项目将有助于阐明肺纤维化形成新的机制，并为研发针对新靶点（eIF3a）的抗肺纤维化药物提供思路。

1）博莱霉素诱发肺纤维化动物肺组织中eIF3a、TGF-β1、 α-SMA及I，III型胶原表达增高；肺纤维化模型给予氟非尼酮治疗后可剂量依赖性的改善肺纤维化症状，并且明显抑制eIF3a、TGF-β1、 α-SMA和I，III胶原的表达。在培养的肺成纤维细胞上TGF-β1能够明显促进细胞增殖，显著上调eIF3a、α-SMA及胶原的表达。氟非尼酮抑制剂能够明显逆转TGF-β1诱导的细胞增殖及α-SMA和I，III型胶原的表达。.2）使用药剂学技术构建氟非尼酮与聚乳酸-羟基乙酸形成微球共聚物(AKF-MS)后，其对百草枯引起的大鼠肺纤维化具有显著治疗效果，且优于普通氟非尼酮制剂治疗效应。.3) 低氧引起的大鼠肺动脉高压，肺血管重构明显，且与TGF-β1表达改变有关。给予不同剂量氟非尼酮治疗可显著缓解肺动脉高压症状；肺动脉平滑肌细胞经TGF-β1处理后出现明显的增殖效应，并且氟非尼酮可抑制TGF-β1引起的平滑肌增殖。.4）胶原沉积（collagen-I, III表达增多）和心肌成纤维细胞分化（α-SMA表达上调）在心室重构中发挥重要作用。干扰eIF3a后，TGF-β1促进心肌成纤维细胞Collagen-I, III和α-SMA表达的作用被抑制。