Unravelling the complex drug-drug interactions of the cardiovascular drugs, verapamil and digoxin, with P-glycoprotein.
Unravelling the complex drug-drug interactions of the cardiovascular drugs, verapamil and digoxin, with P-glycoprotein.
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DOI：
10.1042/bsr20150317
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发表时间：
2016-01-28
影响因子：
4
通讯作者：
Roberts AG
中科院分区：
文献类型：
--
作者：
Ledwitch KV;Barnes RW;Roberts AG
p -糖蛋白（Pgp）在促进维拉帕米和地高辛的药物-药物相互作用（ddi）中起主要作用。在本研究中，我们提出了一个全面的Pgp ddi的分子和机制模型，包括药物结合，ATP水解，运输和构象变化。心血管药物的药物相互作用（ddi）和相关毒性是心血管治疗药物有效联合用药的主要问题。由于药物相互作用和多种心血管药物与外排转运蛋白p -糖蛋白（Pgp）结合，ddi产生了大量的药物毒性，这对于心血管药物来说尤其成问题，因为它们的治疗指标相对较低。钙通道拮抗剂维拉帕米和心糖苷地高辛通过非竞争性抑制地高辛转运，表现出与Pgp的ddi，从而导致地高辛血浆浓度升高和地高辛毒性。在本研究中，维拉帕米诱导的atp酶激活动力学是双相的，这意味着Pgp上至少有两个维拉帕米结合位点，而Pgp偶联的地高辛单相激活的atp酶动力学表明只有一个地高辛结合位点。利用固有蛋白荧光和饱和转移双差（STDD）核磁共振技术探测药物- pgp相互作用，发现维拉帕米在低浓度下对地高辛- pgp相互作用的影响很小，这与药物的同时结合和非竞争性抑制一致。较高浓度的维拉帕米引起地高辛- pgp相互作用的明显破坏，表明重叠和竞争的药物结合位点。这些相互作用与丙烯酰胺猝灭Pgp色氨酸荧光引起的药物诱导构象变化有关。此外，用维拉帕米和地高辛浓度范围测量的pgp偶联atp酶活性动力学与包含维拉帕米对地高辛的非竞争性和竞争性抑制的DDI模型非常吻合。我们将研究结果与之前的转运研究结合起来，构建了一个包含药物结合、ATP水解、转运和构象变化的维拉帕米-地高辛ddi综合模型。
P-glycoprotein (Pgp) plays a major role in promoting drug–drug interactions (DDIs) with verapamil and digoxin. In the present study, we present a comprehensive molecular and mechanistic model of Pgp DDIs encompassing drug binding, ATP hydrolysis, transport and conformational changes. Drug–drug interactions (DDIs) and associated toxicity from cardiovascular drugs represents a major problem for effective co-administration of cardiovascular therapeutics. A significant amount of drug toxicity from DDIs occurs because of drug interactions and multiple cardiovascular drug binding to the efflux transporter P-glycoprotein (Pgp), which is particularly problematic for cardiovascular drugs because of their relatively low therapeutic indexes. The calcium channel antagonist, verapamil and the cardiac glycoside, digoxin, exhibit DDIs with Pgp through non-competitive inhibition of digoxin transport, which leads to elevated digoxin plasma concentrations and digoxin toxicity. In the present study, verapamil-induced ATPase activation kinetics were biphasic implying at least two verapamil-binding sites on Pgp, whereas monophasic digoxin activation of Pgp-coupled ATPase kinetics suggested a single digoxin-binding site. Using intrinsic protein fluorescence and the saturation transfer double difference (STDD) NMR techniques to probe drug–Pgp interactions, verapamil was found to have little effect on digoxin–Pgp interactions at low concentrations of verapamil, which is consistent with simultaneous binding of the drugs and non-competitive inhibition. Higher concentrations of verapamil caused significant disruption of digoxin–Pgp interactions that suggested overlapping and competing drug-binding sites. These interactions correlated to drug-induced conformational changes deduced from acrylamide quenching of Pgp tryptophan fluorescence. Also, Pgp-coupled ATPase activity kinetics measured with a range of verapamil and digoxin concentrations fit well to a DDI model encompassing non-competitive and competitive inhibition of digoxin by verapamil. The results and previous transport studies were combined into a comprehensive model of verapamil–digoxin DDIs encompassing drug binding, ATP hydrolysis, transport and conformational changes.