多药耐药蛋白1(Mrp1)是一种ATP依赖型外流转运蛋白，也是癌症和艾滋病治疗过程中哺乳动物细胞中药物抗性的主要促进因子。在大脑中，Mrp1介导的神经胶质细胞中谷胱甘肽(GSH)的输出是向神经元提供GSH前体的第一步。为了揭示药物诱导的Mrp1介导转运过程的潜在机制，我们研究了抗病毒药物利托那韦对培养的大鼠原代星形胶质细胞的影响。利托那韦通过将Km值从200 nmol/mg降低到28 nmol/mg，强烈刺激了Mrp1介导的谷胱甘肽(GSH)的输出。相反，利托那韦降低了其他Mrp1底物谷胱甘肽二硫化物(GSSG)和双硫咪唑胱甘肽的输出。为了解释这些表面矛盾的观察结果，我们使用大鼠Mrp1的同源模型进行了体外对接分析和分子动力学模拟，以预测利托那韦、GSH和GSSG与Mrp1的结合方式。结果表明，利托那韦结合到Mrp1的双部分结合位点的亲水部分，从而不同地影响Mrp1底物的结合和转运。这些有关利托那韦调节Mrp1介导的输出过程的新见解为更好地理解大脑细胞中的GSH依赖性解毒过程提供了一个新模型。© 2023. 作者。

The Multidrug Resistance Protein 1 (Mrp1) is an ATP-dependent efflux transporter and a major facilitator of drug resistance in mammalian cells during cancer and HIV therapy. In brain, Mrp1-mediated GSH export from astrocytes is the first step in the supply of GSH precursors to neurons. To reveal potential mechanisms underlying the drug-induced modulation of Mrp1-mediated transport processes, we investigated the effects of the antiviral drug ritonavir on cultured rat primary astrocytes. Ritonavir strongly stimulated the Mrp1-mediated export of glutathione (GSH) by decreasing the Km value from 200 nmol/mg to 28 nmol/mg. In contrast, ritonavir decreased the export of the other Mrp1 substrates glutathione disulfide (GSSG) and bimane-glutathione. To give explanation for these apparently contradictory observations, we performed in silico docking analysis and molecular dynamics simulations using a homology model of rat Mrp1 to predict the binding modes of ritonavir, GSH and GSSG to Mrp1. The results suggest that ritonavir binds to the hydrophilic part of the bipartite binding site of Mrp1 and thereby differently affects the binding and transport of the Mrp1 substrates. These new insights into the modulation of Mrp1-mediated export processes by ritonavir provide a new model to better understand GSH-dependent detoxification processes in brain cells.© 2023. The Author(s).