Nicaraven通过靶向巨噬细胞SIRT1改善脓毒症致急性肺损伤的机制研究

It has been shown that SIRT1 is involved in the pathological process of sepsis, but the mechanism of its action remains largely unknown. In our preliminary study, we showed that Nicaraven, a small compound, could increase the expression of SIRT1 in macrophages, inhibit the inflammatory response induced by LPS, and effectively protect against multiple organ damage caused by sepsis. In this study, we investigate the protective effects and anti-inflammatory activity of Nicaraven on sepsis-induced acute lung injury (ALI) in a mouse model as well as in macrophage. By using conditional knockout of macrophage SIRT1 mice and SIRT1 knockdown macrophage, we aim to confirm that the protect effects of Nicaraven against sepsis-induced ALI are mediated by SIRT1. In addition, we further explored the working model and specific targets of Nicaraven on SIRT1/anti-inflammatory signal axis and its upstream signaling pathways, with the aim to elucidate the mechanism of SIRT1 on the pathological process of sepsis-induced ALI. Our study may provide experimental evidence for the treatment of sepsis and its complications, and for the research and development of new anti-inflammatory agents.

研究表明SIRT1参与了脓毒症病理过程的调控，但其调控的具体分子机制尚不清楚。本课题前期结果显示，小分子化合物Nicaraven可上调巨噬细胞SIRT1表达，抑制LPS诱导的巨噬细胞炎症反应，有效地对抗脓毒症导致的多器官损伤。本研究拟采用整体动物脓毒症模型和体外巨噬细胞炎症反应模型，系统研究Nicaraven对脓毒症导致的急性肺损伤（ALI）模型小鼠的保护活性和对巨噬细胞炎症反应的调节作用；利用巨噬细胞特异性敲除SIRT1小鼠和SIRT1敲低的巨噬细胞系，证实Nicaraven对于脓毒症ALI的保护作用是通过SIRT1介导；进一步验证Nicaraven对SIRT1-抗炎信号轴的调控方式和具体作用靶点；探究调控SIRT1信号的上游环节，以期深入阐明SIRT1影响脓毒症ALI病理进程的机制，为临床上脓毒症及并发症的治疗、新型抗炎药物的研究和开发提供实验依据。

Sirt1作为一种去乙酰化酶，可通过对底物蛋白的去乙酰化，参与多种病理过程的调控。本课题前期结果显示，小分子化合物Nicaraven（AVS）可通过上调巨噬细胞Sirt1表达发挥抗炎作用。本研究拟采用小鼠脓毒症模型和体外巨噬细胞炎症反应模型，系统研究AVS对脓毒症急性肺损伤的保护作用，并在此基础上探讨其可能的作用机制。主要研究结果包括：（1）整体动物模型中，AVS对LPS诱导的脓毒症多器官损伤具有显著的保护作用，抑制脓毒症导致的肺部及全身炎症反应，改善小鼠存活率；（2）体外模型显示AVS可有效地抑制LPS诱导的巨噬细胞炎症反应，减少促炎细胞因子的转录和分泌；（3）AVS与阈下剂量的糖皮质激素地塞米松联用具有协同抗炎作用；（4）在机制上，AVS可直接上调Sirt1蛋白表达，进而去乙酰化NF-κB p65亚基，抑制NF-κB信号通路激活，发挥抗炎作用；通过Sirt1敲低和不同抑制剂处理，证实了AVS的抗炎作用是通过AMPK/Sirt1介导；（5）血管内皮细胞作为脓毒症损伤的重要靶点之一，AVS亦可显著改善内皮活化和功能障碍。我们的研究首次将AVS应用于脓毒症急性肺损伤的治疗，证实了其抗炎活性和器官保护作用；将AVS与糖皮质激素联合用药具有抗炎增效作用，为临床上减少糖皮质激素用量、寻找糖皮质激素的替代药物提供了实验依据。研究阐明了AVS对Sirt1-抗炎信号轴调控的具体方式和作用靶点，明确了调控Sirt1信号的上游环节。该项目的完成可为临床上感染性疾病的治疗，抗炎药物靶点选择和药物研发提供重要参考。