Cai Shao-Ai, Hou Ning, Zhao Gan-Jian, Liu Xia-Wen, He Ying-Yan, Liu Hai-Lin, Hua Yong-Quan, Li Li-Rong, Huang Yin, Ou Cai-Wen, Luo Cheng-Feng, Chen Min-Sheng
Department of Cardiology, Guangdong Provincial Biomedical Engineering Technology Research Center for Cardiovascular Disease, Sino-Japanese Cooperation Platform for Translational Research in Heart Failure, Zhujiang Hospital, Southern Medical University, Guangzhou, China.
The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
Front Pharmacol. 2018 Jun 6;9:540. doi: 10.3389/fphar.2018.00540. eCollection 2018.
Puerarin is an isoflavone isolated from . Emerging evidence shown that puerarin possesses therapeutic benefits that aid in the prevention of cardiovascular diseases. In this study, we evaluated the effects of puerarin on oxidative stress and cardiac fibrosis induced by abdominal aortic banding (AB) and angiotensin II (AngII). We also investigated the mechanisms underlying this phenomenon. The results of histopathological analysis, as well as measurements of collagen expression and cardiac fibroblast proliferation indicated that puerarin administration significantly inhibited cardiac fibrosis induced by AB and AngII. These effects of puerarin may reflect activation of Nrf2/ROS pathway. This hypothesis is supported by observed decreases of reactive oxygen species (ROS), decreases Keap 1, increases Nrf2 expression and nuclear translocation, and decreases of collagen expressions in cardiac fibroblasts treated with a combination of puerarin and AngII. Inhibition of Nrf2 with specific Nrf2 siRNA or Nrf2 inhibitor brusatol attenuated anti-fibrotic and anti-oxidant effects of puerarin. The metabolic effects of puerarin were mediated by Nrf2 through upregulation of UDP-glucuronosyltransferase (UGT) 1A1. The Nrf2 agonist tBHQ upregulated protein expression of UGT1A1 over time in cardiac fibroblasts. Treatment with Nrf2 siRNA or brusatol dramatically decreased UGT1A1 expression in puerarin-treated fibroblasts. The results of chromatin immunoprecipitation-qPCR further confirmed that puerarin significantly increased binding of Nrf2 to the promoter region of . Western blot analysis showed that puerarin significantly inhibited AngII-induced phosphorylation of p38-MAPK. A specific inhibitor of p38-MAPK, SB203580, decreased collagen expression, and ROS generation induced by AngII in cardiac fibroblast. Together, these results suggest that puerarin prevents cardiac fibrosis via activation of Nrf2 and inactivation of p38-MAPK. Nrf2 is the key regulator of anti-fibrotic effects and upregulates metabolic enzymes UGT1A1. Autoregulatory circuits between puerarin and Nrf2-regulated UGT1A1 attenuates side effects associated with treatment, but it does not weaken puerarin's pharmacological effects.
葛根素是从……中分离出的一种异黄酮。新出现的证据表明，葛根素具有有助于预防心血管疾病的治疗益处。在本研究中，我们评估了葛根素对腹主动脉缩窄（AB）和血管紧张素II（AngII）诱导的氧化应激和心脏纤维化的影响。我们还研究了这一现象背后的机制。组织病理学分析结果以及胶原蛋白表达和心脏成纤维细胞增殖的测量结果表明，给予葛根素可显著抑制AB和AngII诱导的心脏纤维化。葛根素的这些作用可能反映了Nrf2/ROS通路的激活。用葛根素和AngII联合处理的心脏成纤维细胞中活性氧（ROS）减少、Keap 1减少、Nrf2表达和核转位增加以及胶原蛋白表达减少，支持了这一假设。用特异性Nrf2 siRNA或Nrf2抑制剂布罗苏他抑制Nrf2可减弱葛根素的抗纤维化和抗氧化作用。葛根素的代谢作用由Nrf2通过上调尿苷二磷酸葡萄糖醛酸基转移酶（UGT）1A1介导。Nrf2激动剂叔丁基对苯二酚（tBHQ）随时间上调心脏成纤维细胞中UGT1A1的蛋白表达。用Nrf2 siRNA或布罗苏他处理显著降低了葛根素处理的成纤维细胞中UGT1A1的表达。染色质免疫沉淀-qPCR结果进一步证实，葛根素显著增加了Nrf2与……启动子区域的结合。蛋白质印迹分析表明，葛根素显著抑制AngII诱导的p38丝裂原活化蛋白激酶（p38-MAPK）磷酸化。p38-MAPK的特异性抑制剂SB203580可降低心脏成纤维细胞中AngII诱导的胶原蛋白表达和ROS生成。总之，这些结果表明，葛根素通过激活Nrf2和使p38-MAPK失活来预防心脏纤维化。Nrf2是抗纤维化作用的关键调节因子，并上调代谢酶UGT1A1。葛根素与Nrf2调节的UGT1A1之间的自动调节回路减轻了与治疗相关的副作用，但并未削弱葛根素的药理作用。
