G蛋白偶联受体40通过调控Rho/ROCK信号通路介导肥胖哮喘气道高反应性的研究

Airway hyperresponsiveness (AHR) is a well-established characteristic of asthma. Obesity increases the severity of AHR in individuals with asthma, but the mechanism has not been elucidated. G-protein coupled receptor 40 (GPR40) has been found to induce airway smooth muscle contraction after binding to long-chain fatty acids (LC-FFA), suggesting a correlation between GPR40 and AHR in obese body. Rho/ROCK signal pathway is involved in the regulation of asthma, obesity and GPR40. Our preliminary experimental results show that obese asthmatic mice are characterized by elevated levels of serum free fatty acids and higher GPR40 expression in airway, and GPR40 inhibitor can significantly reduce the AHR of obese asthmatic mice. These results reveal that GPR40 plays an important role in the pathogenesis of AHR in obese asthma. To verify this hypothesis, We will establish the experimental model of obese asthma mice, GPR40-/- mice and obese asthma mice treated with ROCK inhibitor, and combine detection of AHR in both mouse lung function instrument and tracheal rings, as well as ASMC culture and intervention trials to explore the role of GPR40 in obese asthma and demonstrate whether GPR40 in regulation of AHR via Rho/ROCK signal pathway is an important mechanism of AHR in obese asthma, which is of great importance to further understand the pathogenesis of obese asthma.

气道高反应性（AHR）是哮喘的基本特征，肥胖哮喘AHR更为严重，但其机制尚未阐明。G蛋白偶联受体40(GPR40)是长链游离脂肪酸的内源性受体，其活化能诱导气道平滑肌收缩，提示与AHR存在关联。Rho/ROCK信号通路参与肥胖、哮喘和GPR40的调控。我们的预实验结果显示，肥胖哮喘小鼠血清游离脂肪酸水平升高，气道周围GPR40活化上调，给予GPR40抑制剂能改善肥胖哮喘AHR，揭示GPR40在肥胖哮喘发病中的重要地位。本研究将GPR40作肥胖哮喘AHR的潜在治疗靶点，采用肥胖哮喘小鼠、GPR40基因敲除小鼠和ROCK干预动物模型，通过小鼠肺功能仪整体检测和气管环离体检测AHR，开展原代气道平滑肌细胞(ASMC)培养和干预试验，探讨GPR40在肥胖哮喘AHR中的作用，阐明GPR40活化介导的Rho/ROCK通路是否为肥胖哮喘AHR产生的重要机制，将深化肥胖哮喘AHR的发病机制。

气道高反应性（AHR）是哮喘的基本特征，肥胖哮喘AHR更为严重，但其机制尚未阐明。G蛋白偶联受体40(GPR40)是长链游离脂肪酸的内源性受体，其活化能诱导气道平滑肌收缩，提示与AHR存在关联。本研究发现，肥胖哮喘小鼠血清游离脂肪酸水平升高，气道周围GPR40活化上调，给予GPR40抑制剂(DC260126)能降低肥胖哮喘小鼠体重，改善AHR；肺组织病理结果显示，GPR40干预组小鼠的气道炎症、胶原沉积等均亦得到改善；此外，DC260126组小鼠肺组织中GTP-RhoA和ROCK蛋白表达较模型组显著减少。在离体细胞试验中，通过小鼠平滑肌细胞（ASMC）干预试验发现，DC260126能抑制油酸诱导的ASMC增殖和细胞迁移。在机制研究上，我们从ROCK1干预动物模型和离体细胞上均证明GPR40活化介导的Rho/ROCK信号通路是肥胖哮喘AHR产生的重要机制。通过本研究将深化肥胖哮喘的发病机制，并有助于确立GPR40作为肥胖哮喘AHR治疗的潜在药物靶点。