Burke Rob S, Somasuntharam Inthirai, Rearden Paul, Brown Duncan, Deshmukh Sujal V, DiPietro Martha A, DiMuzio Jillian, Eisenhandler Roy, Fauty Scott E, Gibson Christopher, Gindy Marian E, Hamilton Kelly A, Knemeyer Ian, Koeplinger Kenneth A, Kwon Hae Won, Lifsted Traci Q, Menzel Karsten, Patel Mihir, Pudvah Nicole, Rudd Deanne Jackson, Seitzer Jessica, Strapps Walter R, Prueksaritanont Thomayant, Thompson Charles D, Hochman Jerome H, Carr Brian A
Department of Pharmacokinetics, Pharmacodynamics, and Drug Metabolism,, Merck Research Laboratories, Merck & Co., Inc.,, West Point,, Pennsylvania, 19486, USA,
Pharm Res. 2014 Dec;31(12):3445-60. doi: 10.1007/s11095-014-1433-0. Epub 2014 Jul 1.
To develop a tool based on siRNA-mediated knockdown of hepatic P450 oxidoreductase (POR) to decrease the CYP-mediated metabolism of small molecule drugs that suffer from rapid metabolism in vivo, with the aim of improving plasma exposure of these drugs.
siRNA against the POR gene was delivered using lipid nanoparticles (LNPs) into rats. The time course of POR mRNA knockdown, POR protein knockdown, and loss of POR enzyme activity was monitored. The rat livers were harvested to produce microsomes to determine the impact of POR knockdown on the metabolism of several probe substrates. Midazolam (a CYP3A substrate with high intrinsic clearance) was administered into LNP-treated rats to determine the impact of POR knockdown on midazolam pharmacokinetics.
Hepatic POR mRNA and protein levels were significantly reduced by administering siRNA and the maximum POR enzyme activity reduction (~85%) occurred 2 weeks post-dose. In vitro analysis showed significant reductions in metabolism of probe substrates due to POR knockdown in liver, and in vivo POR knockdown resulted in greater than 10-fold increases in midazolam plasma concentrations following oral dosing.
Anti-POR siRNA can be used to significantly reduce hepatic metabolism by various CYPs as well as greatly increase the bioavailability of high clearance compounds following an oral dose, thus enabling it to be used as a tool to increase drug exposure in vivo.
开发一种基于小干扰RNA（siRNA）介导的肝脏细胞色素P450氧化还原酶（POR）敲低的工具，以减少体内代谢迅速的小分子药物的细胞色素P450（CYP）介导的代谢，目的是提高这些药物的血浆暴露量。
使用脂质纳米颗粒（LNPs）将针对POR基因的siRNA递送至大鼠体内。监测POR mRNA敲低、POR蛋白敲低和POR酶活性丧失的时间进程。收获大鼠肝脏以制备微粒体，以确定POR敲低对几种探针底物代谢的影响。将咪达唑仑（一种具有高内在清除率的CYP3A底物）给予经LNP处理的大鼠，以确定POR敲低对咪达唑仑药代动力学的影响。
通过给予siRNA，肝脏POR mRNA和蛋白水平显著降低，给药后2周POR酶活性降低最大（约85%）。体外分析表明，由于肝脏中POR敲低，探针底物的代谢显著减少，体内POR敲低导致口服给药后咪达唑仑血浆浓度增加超过10倍。
抗POR siRNA可用于显著降低各种CYP的肝脏代谢，以及大大提高口服给药后高清除率化合物的生物利用度，从而使其能够用作增加体内药物暴露量的工具。
