基于NLRP3炎症小体信号通路研究α-倒捻子素对尿酸性肾病的肾脏保护作用及机制研究

Renal inflammation induced by hyperuricemia is considered to be a common pathological feature of hyperuricemic nephropathy (HN). An important strategy for controlling HN is to lower the serum uric acid level and alleviate the inflammatory injures in kidney. NLRP3 inflammasome plays an important role in maturation and secretion of inflammatory factors. Regulation of NLRP3 inflammatory signaling pathway will be contributed to the alleviates of inflammatory injures in kidney and controlling HN. In our previous study, we found that α-mangostin significantly decreased the serum urate levels at a dose of 2.0, 4.0, 8.0 mg/kg in hyperuricemic animals, and the hypouricemic action was better than that of benzbromarone. The acute toxicity for oral administrtion of α-mangostin was very low (>5.0 g/kg for mice). These findings indicate that the compound has great potential to be developed as a new agent with high efficiency and low toxicity for controlling HN. However, the renoprotective effects and underling mechanisms of α-mangostin in HN are still unclear. Therefore, in the present study, we are going to investigate the renoprotective effects of α-mangostin in experimental HN and explor the mechanisms associated with NLRP3 inflammatory signal pathway in vivo and in vitro, aiming at providing more fundamental information for the development of α-mangostin as a new candidate drug for the treatment of HN.

高尿酸引起的肾脏炎性损伤是尿酸性肾病（HN）发生发展的病理基础，有效控制血尿酸水平、减轻肾脏炎症反应成为防治HN的重要策略。研究发现NLRP3炎症小体对炎症因子的成熟和分泌起着关键作用，调控NLRP3信号通路有利于减轻炎性损伤和防治HN。课题组前期研究发现源于山竹果皮的一种天然产物α-倒捻子素具有降低血尿酸的作用，灌胃给予2.0 mg/kg即能显著降低高尿酸血症小鼠的血尿酸水平，而口服毒性较低（小鼠急性毒性>5.0 g/kg），显示出高效低毒的特点，有很好的潜在研发前景，已申请国家发明专利（申请号：2201710310971.X），但对HN的防治作用及机制尚未可知。因此，本项目拟在前期工作基础上研究α-倒捻子素对HN的防治作用，并基于NLRP3炎症小体信号通路探讨其对高尿酸引起肾脏炎性损伤的干预作用，在动物、细胞和分子水平阐明其可能的肾脏保护作用机制，为α-倒捻子素的进一步研发奠定基础。

高尿酸引起的肾脏炎性损伤是尿酸性肾病（HN）发生发展的病理基础，有效控制血尿酸水平、减轻肾脏炎症反应成为防治HN的重要策略。NLRP3炎症小体对炎症因子的成熟和分泌起着关键作用，调控NLRP3信号通路有利于减轻炎性损伤和防治HN。本项目从动物、细胞和分子水平研究了α-倒捻子素对HN的防治作用，并基于NLRP3炎症小体信号通路探讨其对高尿酸引起肾脏炎性损伤的干预作用。.研究结果表明，（1）α-倒捻子素对HN肾脏具有改善作用：成功复制了高尿酸性肾病（HN）动物模型，该模型具有血尿酸升高、尿酸排泄分数降低、β2-微球蛋白和微量白蛋白含量显著升高的等征。α-倒捻子素2.0 mg/kg剂量组灌胃给药后能降低HN小鼠的血尿酸水平；α-倒捻子素能降低尿液中β2-微球蛋白和微量白蛋白；2.0、4.0、8.0 mg/kg剂量组显著提高了HN小鼠的尿酸排泄分数；α-倒捻子素灌胃给药后能改善肾脏病理情况，与模型组相比，肾脏HE染色后小鼠肾小球未见异常，肾小管病理损伤有所改善，其水肿变形以及嗜酸性变均减轻。（2）α-倒捻子素对HN肾脏保护作用的分子机制与抑制NLRP3炎症小体信号通路有关：① α-倒捻子素显著抑制HN小鼠肾脏中NLRP3炎症小体组成成分（NLRP3、ASC、Caspase-1）的蛋白表达；α-倒捻子素下调Cathpsin B和P2X7蛋白的表达，从而抑制NLRP3炎症小体的激活。② α-倒捻子素显著降低UA诱导的HK-2细胞炎症因子TNF-α、IL-6、IL-1β、IL-18的基因表达以及NF-κB通路关键蛋白NF-κB、pro-IL1β、pro-IL18的表达，从而改善UA引起的炎症。③ α-倒捻子素显著下调尿酸损伤的HK-2细胞NLRP3、ASC、caspase-1及Cathespin B、P2X7的表达水平，从而对尿酸引起的肾小管损伤具有改善作用。.该项目在动物、细胞和分子水平诠释了α-倒捻子素对尿酸性肾病的作用及其对高尿酸引起肾脏炎性损伤的干预作用机制，为将其研发为治疗尿酸性肾病的候选药物提供实验数据支撑，做出了可行性评价，也为α-倒捻子素的进一步研发奠定基础。