Mueller Cornelius F H, Wassmann Kerstin, Widder Julian D, Wassmann Sven, Chen Chia Hui, Keuler Barbara, Kudin Alexey, Kunz Wolfram S, Nickenig Georg
Medizinische Klinik und Poliklinik II, Universitätsklinikum Bonn, Sigmund Freud Str 25, 53105 Bonn, Germany.
Circulation. 2008 Jun 3;117(22):2912-8. doi: 10.1161/CIRCULATIONAHA.107.747667. Epub 2008 May 27.
We recently showed that the multidrug resistance related protein-1 (MRP1) is important for the management of oxidative stress in vascular cells. However, the underlying mechanism and the in vivo relevance of these findings remain elusive. We hypothesize that inside-outside transport of leukotriene C(4) (LTC(4)) via MRP1 is a substantial proatherogenic mechanism in the vasculature. To test this hypothesis, we investigated the effects of MRP1 inhibition and LTC(4) receptor blockade (Cys-LT1 receptor) in vitro and in vivo.
MRP1 is expressed abundantly in vascular smooth muscle cells (VSMCs). Pharmacological inhibition of MRP1 via MK571 reduces angiotensin II-induced reactive oxygen species release by 59% (L012 fluorescence) in VSMCs. The release of reactive oxygen species after angiotensin II stimulation also is inhibited by blockade of the Cys-LT1 receptor with montelukast. Incubation of VSMCs with recombined LTC(4) causes enhanced rates of reactive oxygen species and proliferation in wild-type and MRP1(-/-) VSMCs. Accordingly, the LTC(4) release in the cell culture supernatant of MRP1(-/-) VSMCs is significantly decreased compared with wild-type cells. To extend our observations to the in vivo situation, atherosclerosis-prone apolipoprotein E-deficient mice on a high-cholesterol diet were treated with placebo, the MRP1 inhibitor MK571, or the Cys-LT1 receptor inhibitor montelukast for 6 weeks. Treatment with MK571 or montelukast reduced vascular reactive oxygen species production, significantly improved endothelial function, and ameliorated atherosclerotic plaque generation by 52% and 61%, respectively.
These findings indicate that MRP1 and LTC(4) exert proatherosclerotic effects and that both MRP1 and LTC(4) are potentially promising targets for atheroprotective therapy.
我们最近发现多药耐药相关蛋白1（MRP1）对血管细胞氧化应激的调控至关重要。然而，其潜在机制及体内相关性仍不清楚。我们推测，MRP1介导的白三烯C4（LTC4）外向转运是血管中一种重要的促动脉粥样硬化机制。为验证这一假设，我们在体内外研究了MRP1抑制和LTC4受体阻断（半胱氨酰白三烯1型受体，Cys-LT1受体）的作用。
MRP1在血管平滑肌细胞（VSMC）中大量表达。通过MK571对MRP1进行药理学抑制，可使血管平滑肌细胞中血管紧张素II诱导的活性氧释放减少59%（基于L012荧光）。孟鲁司特阻断Cys-LT1受体也可抑制血管紧张素II刺激后的活性氧释放。用重组LTC4孵育血管平滑肌细胞，可使野生型和MRP1基因敲除（MRP1-/-）的血管平滑肌细胞活性氧生成速率和增殖率增加。相应地，与野生型细胞相比，MRP1-/-血管平滑肌细胞培养上清液中的LTC4释放量显著降低。为将我们的观察结果拓展到体内情况，给易患动脉粥样硬化的载脂蛋白E缺陷型小鼠喂饲高胆固醇饮食，并分别用安慰剂、MRP1抑制剂MK571或Cys-LT1受体抑制剂孟鲁司特处理6周。MK571或孟鲁司特处理可降低血管活性氧生成，显著改善内皮功能，并分别使动脉粥样硬化斑块形成减少52%和61%。
这些发现表明，MRP1和LTC4具有促动脉粥样硬化作用，二者均可能是动脉粥样硬化保护治疗的潜在有效靶点。
