McAnuff Marie A, Rettig Garrett R, Rice Kevin G
Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, Iowa City, Iowa 52242, USA.
J Pharm Sci. 2007 Nov;96(11):2922-30. doi: 10.1002/jps.20968.
The intracellular delivery of small interfering RNA (siRNA) is a therapeutic strategy to transiently block gene expression. Two silencing RNA strategies utilize either synthetic double stranded RNA or plasmid DNA encoding a short hairpin RNA (shRNA). In the present study, we have quantitatively compared the potency of siRNA (siLuc1) and shRNA (pShagLuc) mediated knockdown of luciferase expression in vivo using hydrodynamic dosing and bioluminescence imaging (BLI). Following hydrodynamic coadministration of siLuc1 or pShagLuc with a plasmid encoding luciferase (pGL3), mice were analyzed for transgene expression by BLI. The knockdown of luciferase expression by siLuc1 or pShagLuc was observed at 3 h and persisted for 3 days. The potency of siLuc1 and pShagLuc was equivalent with maximal effect at 10 microg coadministered with 1 microg of pGL3 resulting in >80% knockdown. Combined dosing of siLuc1 and pShagluc (5 microg each) with 1 microg of pGL3 resulted in >99% knockdown. Analysis of the data established that shRNA was significantly more potent than siRNA at mediating knockdown when compared on a mole basis. The combination of hydrodynamic dosing and BLI to measure siRNA or shRNA mediated knockdown of luciferase provide an attractive in vivo quantitative method to test formulations that target the liver.
小分子干扰RNA（siRNA）的细胞内递送是一种瞬时阻断基因表达的治疗策略。两种RNA干扰策略分别利用合成双链RNA或编码短发夹RNA（shRNA）的质粒DNA。在本研究中，我们使用流体动力学给药和生物发光成像（BLI）定量比较了siRNA（siLuc1）和shRNA（pShagLuc）在体内介导的荧光素酶表达敲低的效力。在将siLuc1或pShagLuc与编码荧光素酶的质粒（pGL3）进行流体动力学共给药后，通过BLI分析小鼠的转基因表达。在3小时时观察到siLuc1或pShagLuc对荧光素酶表达的敲低，并且持续3天。siLuc1和pShagLuc的效力相当，在与1μg pGL3共给药10μg时产生最大效应，导致>80%的敲低。将siLuc1和pShagluc（各5μg）与1μg pGL3联合给药导致>99%的敲低。数据分析表明，在以摩尔为基础进行比较时，shRNA在介导敲低方面比siRNA显著更有效。流体动力学给药和BLI相结合来测量siRNA或shRNA介导的荧光素酶敲低，为测试靶向肝脏的制剂提供了一种有吸引力的体内定量方法。
