Pharmacokinetics, Pharmacodynamics and Drug Metabolism, Merck & Co. & Inc., Rahway, New Jersey 07065, USA.
Mol Pharmacol. 2012 Feb;81(2):220-7. doi: 10.1124/mol.111.074179. Epub 2011 Nov 2.
The development of zinc finger nuclease (ZFN) technology has enabled the genetic engineering of the rat genome. The ability to manipulate the rat genome has great promise to augment the utility of rats for biological and pharmacological studies. A Wistar Hannover rat model lacking the multidrug resistance protein Mdr1a P-glycoprotein (P-gp) was generated using a rat Mdr1a-specific ZFN. Mdr1a was completely absent in tissues, including brain and small intestine, of the knockout rat. Pharmacokinetic studies with the Mdr1a P-gp substrates loperamide, indinavir, and talinolol indicated that Mdr1a was functionally inactive in the blood-brain barrier and intestine in Mdr1a(-/-) rats. To identify possible compensatory mechanisms in Mdr1a(-/-) rats, the expression levels of drug-metabolizing enzyme and transporter-related genes were compared in brain, liver, kidney, and intestine of male and female Mdr1a(-/-) and control rats. In general, alterations in gene expression of these genes in Mdr1a(-/-) rats seemed to be modest, with more changes in female than in male rats. Taken together, our studies demonstrate that the ZFN-generated Mdr1a(-/-) rat will be a valuable tool for central nervous system drug target validation and determining the role of P-gp in drug absorption and disposition.
锌指核酸酶 (ZFN) 技术的发展使得对大鼠基因组进行基因工程成为可能。操纵大鼠基因组的能力为增强大鼠在生物学和药理学研究中的应用提供了巨大的潜力。利用大鼠 Mdr1a 特异性 ZFN 生成了缺乏多药耐药蛋白 Mdr1a P-糖蛋白 (P-gp) 的 Wistar 汉诺威大鼠模型。敲除大鼠的组织中完全不存在 Mdr1a，包括大脑和小肠。Mdr1a P-gp 底物洛哌丁胺、茚地那韦和他林洛尔的药代动力学研究表明，Mdr1a 在 Mdr1a(-/-)大鼠的血脑屏障和肠道中没有功能。为了确定 Mdr1a(-/-)大鼠中可能存在的代偿机制，比较了雄性和雌性 Mdr1a(-/-)和对照大鼠的大脑、肝脏、肾脏和小肠中药物代谢酶和转运体相关基因的表达水平。一般来说，这些基因在 Mdr1a(-/-)大鼠中的表达变化似乎不大，雌性大鼠的变化比雄性大鼠更多。总之，我们的研究表明，ZFN 生成的 Mdr1a(-/-)大鼠将成为验证中枢神经系统药物靶点和确定 P-gp 在药物吸收和处置中的作用的有价值的工具。
