Gao Yuan, Liu Fen, Fang Lei, Cai Runlan, Zong Chuanjie, Qi Yun
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
PLoS One. 2014 May 6;9(5):e96741. doi: 10.1371/journal.pone.0096741. eCollection 2014.
Genkwanin is one of the major non-glycosylated flavonoids in many herbs with anti-inflammatory activities. Although its anti-inflammatory activity in vivo has been reported, the potential molecular mechanisms remain obscure. In this study, by pharmacological and genetic approaches, we explore the anti-inflammatory effects of genkwanin in LPS-activated RAW264.7 macrophages. Genkwanin potently decreases the proinflammatory mediators, such as iNOS, TNF-α, IL-1β and IL-6, at the transcriptional and translational levels without cytotoxicity, indicating the excellent anti-inflammatory potency of genkwanin in vitro. Mechanism study shows that genkwanin significantly suppresses the p38- and JNK-mediated AP-1 signaling pathway and increases the mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP-1) expression at the posttranscriptional level. We also confirmed that microRNA-101 (miR-101) is a negative regulator of MKP-1 expression. Moreover, regardless of miR-101-deficient cells or miR-101-abundant cells, the suppression effects of genkwanin on supernatant proinflammatory mediators' levels are far less than that in respective negative control cells, suggesting that genkwanin exerts anti-inflammatory effect mainly through reducing miR-101 production. However, genkwanin can't affect the level of phospho-Akt (p-Akt), indicating that the phosphorylation of Akt may be not responsible for the effect of genkwanin on miR-101 production. We conclude that genkwanin exerts its anti-inflammatory effect mainly through the regulation of the miR-101/MKP-1/MAPK pathway.
芫花素是许多具有抗炎活性的草药中的主要非糖基化黄酮类化合物之一。尽管其体内抗炎活性已有报道,但其潜在的分子机制仍不清楚。在本研究中,我们通过药理学和遗传学方法,探讨了芫花素在脂多糖(LPS)激活的RAW264.7巨噬细胞中的抗炎作用。芫花素在转录和翻译水平上有效降低促炎介质,如诱导型一氧化氮合酶(iNOS)、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)和白细胞介素-6(IL-6),且无细胞毒性,表明芫花素在体外具有优异的抗炎能力。机制研究表明,芫花素显著抑制p38和JNK介导的AP-1信号通路,并在转录后水平增加丝裂原活化蛋白激酶(MAPK)磷酸酶1(MKP-1)的表达。我们还证实,微小RNA-101(miR-101)是MKP-1表达的负调节因子。此外,无论miR-101缺陷细胞还是miR-101丰富细胞,芫花素对上清液促炎介质水平的抑制作用均远低于各自的阴性对照细胞,这表明芫花素主要通过减少miR-101的产生发挥抗炎作用。然而,芫花素不影响磷酸化Akt(p-Akt)的水平,这表明Akt的磷酸化可能与芫花素对miR-101产生的作用无关。我们得出结论,芫花素主要通过调节miR-101/MKP-1/MAPK途径发挥其抗炎作用。