非诺贝特对血管紧张素Ⅱ诱导RAW264.7细胞Toll样受体4表达、髓过氧化物酶活性及表达的抑制作用

Inhibitory effect of fenofibrate on angiotensin Ⅱ-induced toll-like receptor 4 expression,myeloperoxidase activity and expression in RAW264.7 cells

探讨非诺贝特对血管紧张素Ⅱ(AngⅡ)诱导的小鼠巨噬细胞株RAW264.7细胞Toll样受体4(TLR4)mRNA、蛋白表达及髓过氧化物酶(MPO)活性、mRNA及蛋白表达的影响及其抗炎机制。采用RT-PCR检测TLR4和MPOmRNA水平,Western blotting检测TLR4和MPO的蛋白表达,比色法测定细胞培养上清液中的MPO活性。结果显示,非诺贝特浓度依赖性地减少AngⅡ诱导的RAW264.7细胞TLR4mRNA及蛋白表达,抑制AngⅡ诱导的RAW264.7细胞MPO活性、mRNA及蛋白表达。此外,TLR4阻断剂对AngⅡ诱导的RAW264.7细胞MPO活性有部分的抑制作用,而非诺贝特可增强这一抑制效应。同时非诺贝特明显拮抗TLR4特异性配体脂多糖的促MPO分泌效应。以上结果表明,非诺贝特可下调AngⅡ诱导的RAW264.7细胞TLR4表达,并通过干预TLR4,影响胞内信号转导途径,抑制MPO分泌,减轻炎症反应,这可能是其新的抗炎机制之一。

This study is to investigate the effect of fenofibrate on angiotensin Ⅱ （Ang Ⅱ）-induced toll-like receptor 4 （TLR4） expression, myeloperoxidase （MPO） activity and expression in murine macrophage line RAW264.7 cells and explore its anti-inflammatory mechanism. TLR4 and MPO mRNA levels were analyzed by RT-PCR, and TLR4 and MPO protein expressions were measured by Western blotting. MPO activity in the cell supernatant was assayed with colorimetry. The results showed that fenofibrate reduced Ang Ⅱ-induced mRNA and protein expression of TLR4 and inhibited activity, mRNA and protein expression of MPO in RAW264.7 cells in concentration-dependent manner. In addition, TLR4 blocker partially antagonized the effect of Ang Ⅱ on MPO activity in RAW264.7 cells, and fenofibrate potentiated the inhibitory effect. Meanwhile, fenofibrate significantly suppressed LPS （TLR4 special ligand）-induced MPO activity in RAW264.7 cells. In conclusion, fenofibrate downregulated Ang Ⅱ -induced TLR4 expression and blocked MPO secretion in RAW264.7 cells via interfering with the TLR4-dependent signaling pathway to alleviate inflammation, which might be one of its novel anti-inflammatory mechanisms.