MDR1 and Related Proteins during HIV PI Exposure

描述（申请人提供）：脂质代谢异常及相关代谢紊乱是HIV感染的重要并发症。这些改变背后的机制可能与HIV本身和/或抗逆转录病毒药物治疗有关。MDR1基因产物P-gp是用于治疗HIV、其并发症和药物滥用等相关情况的药物处置、药代动力学和药物相互作用的重要决定因素。HIV蛋白酶抑制剂（pi）与P-gp相互作用，但不同实验范式的结果往往相互矛盾。目前还不清楚在MDR1活跃的不同解剖部位的暴露条件范围内，pi是如何影响MDR1的。PIs可以急性抑制MDR1的功能，但可以导致MDR1在慢性暴露下过表达。个体pi对MDRI的影响能力不同。除了塑造药物底物的动力学特征外，MDR1还是一组参与脂质稳态的ABC转运蛋白之一，包括肠内胆固醇的摄取。另一种ABC转运蛋白ABCA1在胆固醇转运中也很重要，该基因的缺陷可导致家族性高密度脂蛋白缺乏和丹吉尔病。MDR1和ABCA1似乎在某些情况下协同工作，了解pi如何影响MDR1和ABCA1将有助于深入了解pi如何影响胆固醇和其他脂质的运输。此外，MDR1基因启动子区域包含一个NFkB位点，NFkB是一种普遍存在的转录因子，在许多不同的过程中发挥作用，包括动脉粥样硬化和胰岛素抵抗。有限的数据表明利托那韦会影响NFkB的激活，但对于急性和慢性暴露或不同类型的pi是否有不同的影响知之甚少。本提案将探讨pi和MDR1之间的关系，以及其他两种与MDR1相关的蛋白质。细胞培养模型将在一系列生理相关的PI浓度下检查转运蛋白mRNA、蛋白质和功能。NFkB在这些相同细胞中的反应将被确定。此外，将在相同条件下检查细胞培养模型中的胆固醇摄取。这些发现对于理解与pi相关的脂质紊乱以及用于治疗HIV和相关疾病的药物动力学具有重要意义。

DESCRIPTION (provided by applicant): Abnormal lipid metabolism and associated metabolic disorders are important complications of HIV infection. The mechanism(s) underlying these alterations may be related to HIV itself and/or treatment with antiretrovirals. The MDR1 gene product P-gp is an important determinant of the disposition, pharmacokinetics and drug interactions of drugs used in the treatment of HIV, its complications, and related conditions such as drug abuse. The HIV protease inhibitors (PIs) interact with P-gp, but the results from diverse experimental paradigms are often conflicting. It is not established how the PIs affect MDR1 over the range of exposure conditions that occur at the various anatomic sites where MDR1 is active. PIs can acutely inhibit the function of MDR1 but can lead to MDR1 over expression with chronic exposure. The individual PIs differ in their ability to have an impact on MDRI. In addition to shaping the kinetic profile of drug substrates, MDR1 is one of a group of ABC transport proteins involved in lipid homeostasis, including the uptake of cholesterol in the intestine. Another ABC transporter, ABCA1, is also important in cholesterol transport, and defects in this gene can result in familial high-density lipoprotein deficiency and Tangier disease. MDR1 and ABCA1 appear to work together under certain circumstances, and knowing how the PIs affect MDR1 and ABCA1 would provide insight into how the PIs could affect transport of cholesterol and other lipids. Additionally, the MDR1 gene promoter region contains a site for NFkB, a ubiquitous transcription factor with roles in many diverse processes, including atherosclerosis and insulin resistance. Limited data indicate ritonavir affects NFkB activation, but little is known about whether there are differential effects from acute and chronic exposure or across the class of PIs. This proposal will explore the relationship between the PIs and MDR1, as well as two other proteins with relationships to MDR1. Cell culture models will examine transporter mRNA, protein and function over a range of physiologically relevant PI concentrations. The response of NFkB in these same cells will be determined. Additionally, cholesterol uptake in the cell culture model will be examined under the same conditions. The findings will be of importance in understanding lipid disorders related to PIs as well as the kinetics of drugs used to treat HIV and related disorders.