牛磺鹅去氧胆酸激活Nrf2负调控NLRP3炎症体抗炎作用机制的研究

Inflammation is the basic pathological process of numerous diseases. Glucocorticoid and non-steroidal anti-inflammatory drugs (NSAIDs) are the primary anti-inflammatory drugs in veterinary clinic, however, the existing anti-inflammatory drugs cannot meet the needs of the clinic because of their own side effects. In our previously study, we found that taurochenodeoxycholic acid (TCDCA), as a kind of conjugated bile acids with the properties of anti-inflammaton, could ameliorate adjuvant arthritis (AA), however, the mechanisms of amelioration of TCDCA on AA are largely unknown. It was well known that the NLRP3 activity could be inhibited by bile acids, and the production of ROS was decreased by bile acids-stimulated Nrf2 signaling pathway, while ROS was considered as the key factor to induce NLRP3 activation. Therefore, we speculate that the anti-inflammation of TCDCA is mediated by activating Nrf2/ARE pathway negatively regulating NLRP3 inflammasome activity. In this study, molecular pharmacological methods will be used to investigate: ① The negative regulation of TCDCA on NLRP3 inflammsome. ② TCDCA-induced Nrf2 activation in AA rats. ③ The mechanisms of TCDCA on stimulating Nrf2/ARE signaling pathway to negatively regulate NLRP3 inflammasome. The mechanisms of anti-inflammatory effects of TCDCA will be further revealed through this study, which may provide a new way for development of anti-inflammatory and immunomodulatory agents based on bile acids.

炎症是许多疾病共有的基本病理过程，目前兽医临床常用的抗炎药物主要是糖皮质激素与非甾体抗炎药，但因其各自明显的缺点仍难以满足临床需求。我们前期研究发现，牛磺鹅去氧胆酸（TCDCA）作为一种结合型胆汁酸具有显著的抗炎作用，可显著改善佐剂性关节炎（AA）症状，但其确切机制尚不明确。研究发现，胆汁酸具有抑制NLRP3炎症体活性的作用，同时还可激活Nrf2通路抑制ROS的生成，而ROS被认为与NLRP3的活化密切相关，因此，我们推测TCDCA的抗炎作用可能与其激活Nrf2通路抑制ROS的生成，进而负调控NLRP3的活性有关。本研究拟以AA大鼠为研究对象，采用分子药理学方法解析：①TCDCA对NLRP3的负调控作用；②TCDCA对Nrf2通路的激活作用；③TCDCA活化Nrf2负调控NLRP3的作用机制。本研究的开展可深入揭示TCDCA的抗炎作用机制，为以胆汁酸为基础的创新抗炎药物研制奠定基础。

牛磺鹅去氧胆酸（TCDCA）作为一种结合性胆汁酸具有显著的抗炎与免疫调节作用，可显著改善佐剂性关节炎（AA）大鼠足趾肿胀等炎性反应，表现出良好的抗炎作用效果。为了深入揭示TCDCA的抗炎作用机制，本研究以AA大鼠成纤维样滑膜细胞（FLS）为主要研究对象，观察了TCDCA对FLS细胞中NLRP3炎症体的影响，研究结果发现，100 μM的TCDCA可显著抑制NLRP3炎症体的活性，抑制IL-1β与Caspase-1的成熟与剪切；同时TCDCA还以通过提高p62蛋白的表达水平抑制Keap1的表达，进而有效激活Nrf2/ARE抗氧化信号通路，提高Nrf2下游HO-1、NQO1的表达水平；另外，TCDCA还可以有效抑制线粒体ROS（mtROS）的产生，减轻LPS与ATP共同刺激对线粒体膜电位的影响。Nrf2/ARE的激活可以有效抑制ROS的生成，而ROS（特别是mtROS）是激活NLRP3炎症体的主要原因之一，因此，我们通过Nrf2特异性抑制剂ML385预处理FLS细胞，发现TCDCA对NLRP3炎症体的抑制作用显著降低，提示TCDCA对NLRP3的负调控作用与其激活Nrf2/ARE信号通路抑制mtROS的生成相关。本研究进一步揭示了TCDCA的抗炎作用机制，为以胆汁酸为基础的创新抗炎药物开发提供了重要的理论依据。