Glypican3-Wnt通路介导气道局部炎症调控急性肺损伤的分子机制

In the clinical, acute lung injury has very complicated pathogenesises. The lack of effective drug treatments leads to its high fatality rate, which shows the importance of finding specific and precise therapies. Our previous trial study showed an increased protective effect on acute lung injury by endotracheal administration compared to systematic administration, pointing out one possibility that airway inflammatory might be a very important link during acute lung injury occurrence and progress. Using protein-chip technique, we identified a protein called Glypican-3(GPC3), a significantly enhanced factor in the blood samples of acute lung injury patients. Intriguingly, our previous study indicated GPC3 had an elevated expression in acute lung injury model. Furthermore, GPC3 is detectable in airway epithelial cell. Previous studies indicate GPC3 can regulate two signal pathways including Wnt/JNK, Wnt/β-catenin which related to inflammation or epithelial integrity. Therefore, we hypothesize that GPC3 is required for airway local inflammation of acute lung injury. The aim of this study is to investigate the molecular mechanisms of GPC3 in airway local inflammation of acute lung injury via suppression on Wnt/β-catenin and activation on Wnt/JNK signal pathway. Using overexpression and knock-down techniques in vitro and vivo, we will further evaluate the functions of GPC3-mediated Wnt/β-catenin and Wnt/JNK involved in acute lung injury, which might provide a new potential therapeutic target for acute lung injury.

急性肺损伤缺乏有效的治疗，病死率高，其发病机理复杂。我们前期研究发现：气道内局部给药比全身给药更能预防和减轻肺损伤，提示气道局部炎症可能是肺损伤发生发展的重要环节；研究肺损伤患者蛋白谱时发现GPC3明显升高，肺损伤动物模型中也发现气道上皮细胞GPC3表达升高。因此推测GPC3是否与气道局部炎症及肺损伤发生发展密切相关。文献报道GPC3可调控Wnt/JNK、Wnt/β-catenin等与炎症及上皮完整性相关的通路。我们假设：致病因素通过GPC3，抑制Wnt/β-catenin通路，破坏上皮完整性，激活Wnt/JNK通路，促进炎症因子释放，介导气道局部炎症，调控急性肺损伤的发生、发展。采用SiRNA转染等技术，通过特异性过表达或缺失表达GPC3的细胞与动物模型，研究GPC3-Wnt通路对肺损伤的影响及分子机制，阐明GPC3在肺损伤中的作用和作为治疗肺损伤靶点的可能性。

急性肺损伤是一种常见、严重的临床疾病，我们在研究临床急性肺损伤/急性呼吸窘迫综合征患者血液蛋白谱检测时，发现磷脂酰肌醇蛋白多糖-3（Glypican-3，GPC3）在肺炎相关ALI/ARDS患者血清中含量急剧升高。本研究中，我们假设GPC3-WNT通路在局部炎症具有一定的调控作用。我们体内实验证明急性肺损伤炎症时期Glypican3表达量升高，且定位于气道上皮细胞以及部分肺泡细胞。我们发现LPS诱导16HBE细胞中GPC3及炎症因子等表达，GPC3促进气道上皮细胞中炎症因子等表达，提示GPC3具有重要的促炎症作用，是肺损伤发生发展过程中的一个重要环节。我们发现JNK通路抑制剂能抑制GPC3对16HBE细胞的促炎作用，干扰GPC3后JNK通路的活性在LPS刺激时有所减弱，提示GPC3在炎症微环境下气道上皮细胞中介导GPC3-WNT-JNK通路，参与炎症过程。我们利用气道内滴入LPS制造急性肺损伤小鼠模型，并予以GPC3 siRNA预处理，发现GPC3干扰后LPS刺激时炎症较LPS组有所减轻。我们的研究初步阐明了Glypican3在急性肺损伤中的作用，并报道了Glypican3-WNT-JNK通路调控急性肺损伤的分子机制。