Yamazaki H, Hatanaka N, Kizu R, Hayakawa K, Shimada N, Guengerich F P, Nakajima M, Yokoi T
Division of Drug Metabolism, Faculty of Pharmaceutical Sciences, Kanazawa University, 13-1 Takara-machi, 920-0934, Kanazawa, Japan.
Mutat Res. 2000 Dec 20;472(1-2):129-38. doi: 10.1016/s1383-5718(00)00138-8.
The genotoxicities of four samples of diesel exhaust particle (DEP) extracts (DEPE) and nine nitroarenes found in DEPE were investigated after activation catalyzed by human cytochrome P450 (P450) family 1 enzymes co-expressed with NADPH-cytochrome P450 reductase (NPR) in Escherichia coli membranes. The DEPE samples induced umu gene expression in Salmonella typhimurium TA1535/pSK1002 without any P450 system and were further activated by human P450 1B1/NPR membranes. Moderate activation of the DEPE sample by P450 1A2/NPR membranes was also observed, but not by either P450 1A1/NPR or NPR membranes. 1-Nitropyrene (1-NP) was strongly activated by human P450 1B1/NPR membranes. 1,8-Dinitropyrene (1,8-DNP) was most highly activated by P450 1A1 and 1B1 systems for the three DNPs tested. In contrast, 1, 3-DNP was inactivated by P450 1A1/NPR, 1A2/NPR, and 1B1/NPR systems and slightly activated by NPR membranes. 2-Nitrofluoranthene (2-NF) and 3-nitrofluoranthene (3-NF) showed activities similar to 1-NP after bioactivation by P450 1B1/NPR membranes. However, the genotoxicities of 6-nitrochrysene, 7-nitrobenz[a]anthracene, and 6-nitrobenzo[a]pyrene were all weak in the present assay system. Apparent genotoxic activities of DEPE were very low compared with standard nitroarenes in the presence of P450s, possibly because unknown component(s) of DEPE had inhibitory effects on the bioactivation of 1-NP and 1,8-DNP catalyzed by human P450 1B1. These results suggest that environmental chemicals existing in airborne DEP, in addition to 1-NP, 1,6-DNP, 1,8-DNP, 2-NF, and 3-NF, can be activated by human P450 1B1. Biological actions of air pollutants such as nitroarenes to human extrahepatic tissues may be of concern in tissues in which P450 1B1 is expressed.
在大肠杆菌膜中与NADPH - 细胞色素P450还原酶（NPR）共表达的人细胞色素P450（P450）家族1酶催化激活后，研究了四种柴油废气颗粒（DEP）提取物（DEPE）样品以及在DEPE中发现的九种硝基芳烃的遗传毒性。DEPE样品在没有任何P450系统的情况下可诱导鼠伤寒沙门氏菌TA1535/pSK1002中的umu基因表达，并被人P450 1B1/NPR膜进一步激活。还观察到P450 1A2/NPR膜对DEPE样品有中度激活作用，但P450 1A1/NPR膜或NPR膜均未出现这种情况。1 - 硝基芘（1 - NP）被人P450 1B1/NPR膜强烈激活。在所测试的三种二硝基芘中，1,8 - 二硝基芘（1,8 - DNP）被P450 1A1和1B1系统激活程度最高。相比之下，1,3 - 二硝基芘（1,3 - DNP）被P450 1A1/NPR、1A2/NPR和1B1/NPR系统灭活，并被NPR膜轻微激活。2 - 硝基荧蒽（2 - NF）和3 - 硝基荧蒽（3 - NF）在被P450 1B1/NPR膜生物激活后表现出与1 - NP相似的活性。然而，在本检测系统中，6 - 硝基 Chrysene、7 - 硝基苯并[a]蒽和6 - 硝基苯并[a]芘的遗传毒性均较弱。在存在P450的情况下，DEPE的表观遗传毒性活性与标准硝基芳烃相比非常低，这可能是因为DEPE的未知成分对人P450 1B1催化的1 - NP和1,8 - DNP的生物激活有抑制作用。这些结果表明，除了1 - NP、1,6 - DNP、1,8 - DNP、2 - NF和3 - NF之外，空气中DEP中存在的环境化学物质可被人P450 1B1激活。在表达P450 1B1的组织中，硝基芳烃等空气污染物对人体肝外组织的生物学作用可能值得关注。
