赖氨酰氧化酶样蛋白2在结缔组织病肺纤维化中的作用及机制

Interstitial lung disease related connective tissue disease often results in lung fibrosis, but effective therapeutic methods have not been found yet. To find the prognostic indicator and therapeutic approach for this disease has great significance. Some studies also found lysyl oxidase like-2 (LOXL2) will induce epithelial-to-mesenchymal transition(EMT) in tumors. There are also studies found LOXL2 is associated with various inflammatory factors and will increase lung mesenchymal markers, hence proposed the function of LOXL2 is related to TGF-β. Our group proposed the following hypothesis: LOXL2 plays a critical role in the pathogenesis of lung fibrosis which is caused by connective tissue disease related interstitial lung disease. Our research was to observe the effect of LOXL2 on the pathogenesis of lung fibrosis in animal models. Meanwhile, we investigate the function of LOXL2 in the procedure of epithelial to mesenchymal transiton in epithelioid cells of lung alveoli and the process of fibroblast maturation and proliferation. Then we are going to clarify the regulation of LOXL2 on TGFβ/Smad/Snail signaling pathway using gene-silencing technique. The ultimate objective is try to reveal the pathogenic mechanism of interstitial lung disease related connective tissue disease inducing lung fibrosis. This research will search for new biomarkers about early diagnosis and outcome of interstitial lung disease related connective tissue disease and will provide evidence for new therapeutic targets.

结缔组织病相关间质性肺疾病结局为肺纤维化，尚无有效治疗手段，因此寻找疾病预后指标及治疗途径有重要价值。研究发现赖氨酰氧化酶样蛋白2（LOXL2）在肿瘤中可诱导上皮细胞向间质细胞转型；LOXL2与多种炎症因子有关并能诱导肺间质标志物上调，LOXL2作用可能与转化生长因子β(TGF-β)有关。故本课题组提出假说：LOXL2在结缔组织病相关间质性肺疾病导致肺纤维化的致病机制中发挥重要作用。本研究拟探讨LOXL2对疾病动物模型肺纤维化发生发展的影响，并采用基因沉默技术证实；探寻LOXL2在肺泡上皮细胞向间质细胞转型及成纤维细胞分化成熟与增殖中的影响，通过LOXL2对TGFβ/Smad/Snail通路的影响，了解LOXL2的作用途径及影响因素。本研究有望揭示结缔组织病相关间质性肺疾病导致肺纤维化的部分发病机制，发现结缔组织病相关间质性肺疾病导致肺纤维化有效的诊断和预后指标及新的治疗途径及靶点。

结缔组织病相关间质性肺疾病结局为肺纤维化，尚无有效治疗手段，因此寻找疾病预后指标及治疗途径有重要价值。研究发现赖氨酰氧化酶样蛋白2（LOXL2）在肿瘤中可诱导上皮细胞向间质细胞转型；LOXL2与多种炎症因子有关并能诱导肺间质标志物上调，LOXL2作用可能与转化生长因子β(TGF-β)有关。本课题组在成功制作了博来霉素诱导的小鼠肺纤维化（Pulmonary Fibrosis）模型中，分离提取小鼠肺成纤维细胞和肺泡上皮细胞进行培养，并在细胞和动物水平研究赖氨酰氧化酶样蛋白-2（LOXL-2）对 TGFβ/Smad/Snail 通路的影响，以及在肺泡上皮细胞向间质细胞转型和成纤维细胞分化成熟与增殖对动物模型肺纤维化发生发展中的影响。研究发现在博来霉素诱导的肺纤维化小鼠的血清、肺匀浆和肺组织中LOXL-2的表达显著增加。沉默LOXL-2可显著降低肺成纤维细胞和肺泡上皮细胞的增殖，降低细胞上清液中白介素-6和胶原蛋白I的水平。此外，沉默LOXL-2抑制了p-Smad2/3、Smad4和Snail的表达，同时促进了Smad7的表达。综合分析目前LOXL-2在肺纤维化中的数据，表明LOXL-2通过调节TGF-β/Smad信号通路在纤维化发生中的重要作用。研究的结果一方面证实LOXL2作为结缔组织病相关间质性肺疾病早期病变的预测因子，为早期治疗提供可能，另一方面明确 LOXL2 在结缔组织病相关间质性肺疾病中的作用机制, 进一步阐释结缔组织病相关间质性肺疾病中的致病机制，为这一严重致死、致残疾病提供新的可能的治疗靶点。