Indian Institute of Toxicology Research, Lucknow, U.P., India.
Biochem Pharmacol. 2010 Apr 15;79(8):1182-8. doi: 10.1016/j.bcp.2009.11.021. Epub 2009 Nov 29.
In an attempt to develop blood lymphocyte cytochrome P450 expression profile as a surrogate to monitor tissue enzyme, the present study aimed to identify the expression and regulation of polycyclic aromatic hydrocarbons (PAHs) responsive CYPs in freshly prepared rat blood lymphocytes. Semi-quantitative and RT-PCR studies demonstrated constitutive and inducible mRNA expression of CYP1A1, 1A2, 1B1 isoenzymes and the associated transcription factors, aryl hydrocarbon receptor (AhR) and AhR translocator (ARNT) in blood lymphocytes. Absolute quantification using RT-PCR revealed several fold lower basal expression of CYP1A1, 1A2 and 1B1 in lymphocytes when compared to the liver. However, significant increase in the mRNA expression of these isoenzymes as well as AhR and ARNT in lymphocytes following pretreatment with 3-methylcholanthrene (MC) have demonstrated that responsiveness is retained in the blood lymphocytes, though the magnitude of increase is several fold lower when compared to liver. This increase in the mRNA expression was found to be associated with an increase in the protein expression of CYP1A1 and 1A2 in blood lymphocytes. Further, CYPs expressed in blood lymphocytes catalysed the O-dealkylation of 7-ethoxy- and 7-methoxyresorufins (ER or MR), though the reactivity was several fold lower in lymphocytes when compared to the liver enzyme. Our data providing quantitative evidence for similarities in the regulation of PAH-regulated CYP in uncultured and non-mitogen stimulated blood lymphocytes with the liver enzyme has led us to suggest that blood lymphocytes could be used as a surrogate to monitor tissue expression of CYPs.
为了开发血液淋巴细胞细胞色素 P450 表达谱作为监测组织酶的替代方法，本研究旨在鉴定新鲜制备的大鼠血液淋巴细胞中多环芳烃（PAHs）反应性 CYP 的表达和调控。半定量和 RT-PCR 研究表明，CYP1A1、1A2、1B1 同工酶及其相关转录因子芳烃受体（AhR）和 AhR 转运蛋白（ARNT）在血液淋巴细胞中呈组成型和诱导型表达。使用 RT-PCR 进行绝对定量显示，与肝脏相比，CYP1A1、1A2 和 1B1 的基础表达在淋巴细胞中低几个数量级。然而，用 3-甲基胆蒽（MC）预处理后，这些同工酶以及 AhR 和 ARNT 的 mRNA 表达显著增加，表明血液淋巴细胞中仍保留了反应性，尽管与肝脏相比，增加幅度低几个数量级。这种 mRNA 表达的增加与 CYP1A1 和 1A2 在血液淋巴细胞中的蛋白表达增加有关。此外，血液淋巴细胞中表达的 CYP 催化 7-乙氧基resorufin（ER）和 7-甲氧基resorufin（MR）的 O-脱烷基化，尽管与肝脏酶相比，淋巴细胞中的反应性低几个数量级。我们的数据提供了定量证据，证明未培养和非有丝分裂刺激的血液淋巴细胞中 PAH 调节的 CYP 的调控与肝脏酶相似，这使我们提出血液淋巴细胞可用作监测组织中 CYP 表达的替代物。
