The Crosstalk Between Nrf2 and AMPK Signal Pathways Is Important for the Anti-Inflammatory Effect of Berberine in LPS-Stimulated Macrophages and Endotoxin-Shocked Mice
The Crosstalk Between Nrf2 and AMPK Signal Pathways Is Important for the Anti-Inflammatory Effect of Berberine in LPS-Stimulated Macrophages and Endotoxin-Shocked Mice
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DOI：
10.1089/ars.2012.5116
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发表时间：
2014-02-01
影响因子：
6.6
通讯作者：
Xiao, Hengyi
中科院分区：
文献类型：
--
作者：
Mo, Chunfen;Wang, Ling;Xiao, Hengyi
目的：AMP激活的蛋白激酶(AMPK)对氧化应激的反应最近有报道，但这种反应的下游信号大多还不清楚。同时，核因子红系相关因子-2(Nrf2)的上游激活事件仍不清楚，Nrf2是抗氧化反应的关键转录激活因子。在本研究中，我们研究了AMPK和Nrf2信号通路在脂多糖(LPS)触发的炎症系统中的关系，其中已知的AMPK激活剂黄连素(BBR)用于抑制炎症。结果和创新：在炎症巨噬细胞中，BBR减弱了内毒素诱导的炎症基因(诱导型一氧化氮合酶[iNOS]、环氧合酶-2[COX2]、白介素[IL]-6)的表达，以及一氧化氮和活性氧物种的产生，但增加了Nrf2靶向抗氧化基因(NADPH Quone氧化还原酶-1[NQO-1]、血红素加氧酶-1[HO-1])的转录，以及NRF2蛋白的核定位和磷酸化。重要的是，我们发现BBR诱导的Nrf2的激活是AMPK依赖的，因为药物或基因失活AMPK阻止了Nrf2的激活。与体外实验一致，BBR下调了内毒素注射小鼠肺组织促炎基因的表达，但上调了Nrf2靶向基因的表达，这些作用在Nrf2缺陷小鼠中得到减弱。此外，当Nrf2耗尽时，BBR对内毒素休克小鼠的存活时间延长和血浆氧化还原调节的作用大大减弱。结论：我们的结果证实了AMPK和NRF2通路的汇聚，这种交汇对于BBR对内毒素刺激的巨噬细胞和内毒素休克小鼠的抗炎作用是必不可少的。揭示这一交叉对于理解能量稳态和抗氧化反应之间的关系具有重要意义，并可能有助于开发抗炎症性疾病的新治疗策略。
Aims: The response of AMP-activated protein kinase (AMPK) to oxidative stress has been recently reported but the downstream signals of this response are largely unknown. Meanwhile, the upstream events for the activation of nuclear factor erythroid-2-related factor-2 (Nrf2), a critical transcriptional activator for antioxidative responses, remain unclear. In the present study, we investigated the relationship between AMPK and Nrf2 signal pathways in lipopolysaccharide (LPS)-triggered inflammatory system, in which berberine (BBR), a known AMPK activator, was used for inflammation suppression. Results and Innovation: In inflammatory macrophages, BBR attenuated LPS-induced expression of inflammatory genes (inducible nitric oxide synthase [iNOS], cyclooxygenase-2 [COX2], interleukin [IL]-6), and the generation of nitric oxide and reactive oxygen species, but increased the transcription of Nrf2-targeted antioxidative genes (NADPH quinone oxidoreductase-1 [NQO-1], heme oxygenase-1 [HO-1]), as well as the nuclear localization and phosphorylation of Nrf2 protein. Importantly, we found BBR-induced activation of Nrf2 is AMPK-dependent, as either pharmacologically or genetically inactivating AMPK blocked the activation of Nrf2. Consistent with in vitro experiments, BBR down-regulated the expression of proinflammatory genes but upregulated those of Nrf2-targeted genes in lungs of LPS-injected mice, and these effects were attenuated in Nrf2-deficient mice. Moreover, the effect of BBR on survival time extension and plasma redox regulation in endotoxin-shocked mice was largely weakened when Nrf2-depleted. Conclusions: Our results demonstrate convergence between AMPK and Nrf2 pathways and this intersection is essential for anti-inflammatory effect of BBR in LPS-stimulated macrophages and endotoxin-shocked mice. Uncovering this intersection is significant for understanding the relationship between energy homeostasis and antioxidative responses and may be beneficial for developing new therapeutic strategies against inflammatory diseases.