Investigation of the involvement of oxidative stress in metabolic syndrome and the development of new anti-oxidants

我们使用体内和体外策略研究了氧化应激在代谢综合征中的可能参与。我们研究了血管紧张素II(Ang II)对胰岛素诱导的血管平滑肌细胞(VSMC)葡萄糖摄取的影响及其细胞内机制。血管紧张素转换酶II或氧化应激抑制胰岛素诱导的葡萄糖摄取，这种作用可被ERK抑制剂逆转，但不能被JNK抑制剂逆转。在慢性系膜增生性肾小球肾炎(GN)大鼠模型中，肾小球BMK1在发病第28天和56天即可观察到BMK1的活化。在培养的大鼠系膜细胞中，Ang II和氧化应激诱导BMK1激活，提示Ang II和氧化应激参与了炎症诱导的代谢综合征。我们还发现，在培养的大鼠VSMC中，BMK1被H_2O_2以时间和浓度依赖的方式激活。同时观察到Src酪氨酸激酶的激活与BMK1的激活是平行的。我们利用siRNA转染技术建立了BMK1基因敲除VSMC的实验模型。此外，我们的结果还表明，在抑制BMK1表达的BMK1 siRNA转染的VSMC中加入H_2O_2会增加细胞死亡。这些结果表明，BMK1可能在保护细胞免受氧化应激诱导的细胞凋亡中发挥重要作用，这种作用是由Src介导的信号通路介导的。C-Src和BMK1可能成为临床治疗代谢综合征的靶点。

We investigated the possible involvement of oxidative stress in metabolic syndrome using in vivo and in vitro strategies. We examined the effect of angiotensin II (Ang II) on insulin-induced glucose uptake and its intracellular mechanisms in cultured vascular smooth muscle cells (VSMC). Ang II or oxidative stress inhibited insulin-induced glucose uptake, which was reversed by an ERK inhibitor but not by a JNK inhibitor in VSMC. In the chronic mesangioproliferative glomerulonephritis (GN) rat model using uninephrectomy and anti-Thy-1 antibody injection, activation of BMK1 was observed in the glomeruli at day 28 and 56 of GN. In the cultured rat mesangial cells, Ang II and oxidative stress induced BMK1 activation, suggesting that Ang II and oxidative stress involves in an inflammation-induced metabolic syndrome. We also found that BMK1 was activated by H2O2 in a time- and concentration-dependent manner in cultured rat VSMC. The activation of Src tyrosine kinase was also observed which was parallel with the BMK1 activation. We established an experimental model of BMK1 knock downed VSMC using siRNA transfection technology. Furthermore, our results also showed that cell death was increased when H2O2 was added into the BMK1 siRNA transfected VSMC in which BMK1 expression was inhibited. From these findings, it was suggested that BMK1 may play an essential role in protecting cells from oxidative stress-induced apoptosis, which is mediated by Src-mediated signaling pathway. c-Src and BMK1 may be possible targets for the treatment of metabolic syndrome clinically.