Callahan Shellie M, Boquet Michael P, Ming Xin, Brunner Lane J, Croyle Maria A
College of Pharmacy, Division of Pharmaceutics, The University of Texas at Austin, Austin, TX 78712-1074, USA.
J Gene Med. 2006 May;8(5):566-76. doi: 10.1002/jgm.884.
Systemic administration of a first-generation adenovirus expressing E. coli beta-galactosidase (AdlacZ) alters expression and function of two hepatic drug-metabolizing enzymes, cytochrome P450 (CYP) 3A2 and 2C11, for 14 days. The objective of these studies was to determine how the transgene cassette influences CYP expression and function.
Sprague-Dawley rats were given 5.7 x 10(12) viral particles (vp)/kg of either: AdlacZ, Ad expressing murine erythropoietin (Epo), Ad without a transgene (Null), or phosphate-buffered saline (Vehicle). Hepatic CYP protein expression, activity, mRNA and alanine aminotransferase (ALT) levels were analyzed 0.25, 1, 4, and 14 days following a single intravenous injection.
Administration of Epo did not alter CYP3A2 activity, but induced RNA levels by a factor of 2 at 4 and 14 days (P< or =0.01). This vector suppressed CYP2C11 activity levels by 45% at 1 day (P< or =0.05) and RNA levels throughout the study period (P< or =0.05). The Null vector suppressed CYP3A2 activity by 36, 63, 34, and 45% at 0.25, 1, 4 and 14 days, respectively (P< or =0.05). CYP2C11 activity was suppressed 1 day after administration (41%) and RNA levels were suppressed at 6 h (53%) and 1 day (36%, P< or =0.05). In contrast, AdlacZ suppressed both CYP3A2 and 2C11 at all time points.
The immunogenic and biological nature of the transgene cassette can influence changes in CYP3A2, but not the 2C11 isoform. The shift in transcription and translation of protein for maintenance of physiologic homeostasis to production of viral proteins and transgene product and their associated toxicity during viral infection may explain our observations.
全身给予表达大肠杆菌β-半乳糖苷酶的第一代腺病毒（AdlacZ）可使两种肝脏药物代谢酶，即细胞色素P450（CYP）3A2和2C11的表达及功能改变14天。这些研究的目的是确定转基因盒如何影响CYP的表达及功能。
给Sprague-Dawley大鼠静脉注射5.7×10¹²病毒颗粒（vp）/kg的以下物质：AdlacZ、表达小鼠促红细胞生成素（Epo）的腺病毒、无转基因的腺病毒（空载体）或磷酸盐缓冲盐水（载体对照）。在单次静脉注射后0.25、1、4和14天分析肝脏CYP蛋白表达、活性、mRNA及丙氨酸转氨酶（ALT）水平。
给予Epo未改变CYP3A2活性，但在4天和14天时使RNA水平升高2倍（P≤0.01）。该载体在1天时使CYP2C11活性水平降低45%（P≤0.05），并在整个研究期间使RNA水平降低（P≤0.05）。空载体在0.25、1、4和14天时分别使CYP3A2活性降低36%、63%、34%和45%（P≤0.05）。CYP2C11活性在给药1天后降低（41%），RNA水平在6小时时降低（53%），1天时降低（36%，P≤0.05）。相比之下，AdlacZ在所有时间点均抑制CYP3A2和2C11。
转基因盒的免疫原性和生物学特性可影响CYP3A2的变化，但不影响2C11同工型。转录和翻译从维持生理稳态的蛋白质转变为病毒感染期间病毒蛋白和转基因产物的产生及其相关毒性，这可能解释了我们的观察结果。
