Department of Applied Chemistry and Biochemistry, National Institute of Technology, Wakayama College, 77 Noshima, Nada, Gobo-shi, Wakayama, 644-0023, Japan.
Department of Material Science and Engineering, Material Science and Engineering, Wakayama National College of Technology, Gobo-shi, Wakayama, 644-0023, Japan.
Environ Mol Mutagen. 2019 Dec;60(9):792-806. doi: 10.1002/em.22321. Epub 2019 Aug 16.
Aristolochic acids (AAs) are human nephrotoxins and carcinogens found in concoctions of Aristolochia plants used in traditional medicinal practices worldwide. Genotoxicity of AAs is associated with the formation of active species catalyzed by metabolic enzymes, the full repertoire of which is unknown. Recently, we provided evidence that sulfonation is important for bioactivation of AAs. Here, we employ Salmonella typhimurium umu tester strains expressing human N-acetyltransferases (NATs) and sulfotransferases (SULTs), to study the role of conjugation reactions in the genotoxicities of N-hydroxyaristolactams (AL-I-NOH and AL-II-NOH), metabolites of AA-I and AA-II. Both N-hydroxyaristolactams show stronger genotoxic effects in umu strains expressing human NAT1 and NAT2, than in the parent strain. Additionally, AL-I-NOH displays increased genotoxicity in strains expressing human SULT1A1 and SULT1A2, whereas AL-II-NOH shows enhanced genotoxicity in SULT1A1/2 and SULT1A3 strains. 2,6-Dichloro-4-nitrophenol, SULTs inhibitor, reduced umuC gene expression induced by N-hydroxyaristolactams in SULT1A2 strain. N-hydroxyaristolactams are also mutagenic in parent strains, suggesting that an additional mechanism(s) may contribute to their genotoxicities. Accordingly, using putative SULT substrates and inhibitors, we found that cytosols obtained from human kidney HK-2 cells activate N-hydroxyaristolactams in aristolactam-DNA adducts with the limited involvement of SULTs. Removal of low-molecular-weight reactants in the 3.5-10 kDa range inhibits the formation of aristolactam-DNA by 500-fold, which could not be prevented by the addition of cofactors for SULTs and NATs. In conclusion, our results demonstrate that the genotoxicities of N-hydroxyaristolactams depend on the cell type and involve not only sulfonation but also N,O-acetyltransfer and an additional yet unknown mechanism(s). Environ. Mol. Mutagen. 2019. © 2019 Wiley Periodicals, Inc.
马兜铃酸（AAs）是人类肾毒素和致癌物，存在于世界各地用于传统医学实践的马兜铃属植物制剂中。AA 的遗传毒性与代谢酶催化的活性物质的形成有关，而代谢酶的全部组成尚不清楚。最近，我们提供了磺化在 AA 生物活化中的重要性的证据。在这里，我们使用表达人 N-乙酰基转移酶（NATs）和磺基转移酶（SULTs）的鼠伤寒沙门氏菌 umu 测试菌株，研究结合反应在 N-羟基马兜铃内酰胺（AL-I-NOH 和 AL-II-NOH）的遗传毒性中的作用，AA-I 和 AA-II 的代谢物。两种 N-羟基马兜铃内酰胺在表达人 NAT1 和 NAT2 的 umu 菌株中的遗传毒性均强于亲本菌株。此外，AL-I-NOH 在表达人 SULT1A1 和 SULT1A2 的菌株中显示出增强的遗传毒性，而 AL-II-NOH 在 SULT1A1/2 和 SULT1A3 菌株中显示出增强的遗传毒性。2,6-二氯-4-硝基苯酚，SULTs 抑制剂，降低 SULT1A2 菌株中 N-羟基马兜铃内酰胺诱导的 umuC 基因表达。N-羟基马兜铃内酰胺在亲本菌株中也是致突变的，这表明可能存在其他机制导致其遗传毒性。因此，使用推定的 SULT 底物和抑制剂，我们发现人肾 HK-2 细胞的细胞质在有限涉及 SULTs 的马兜铃内酰胺-DNA 加合物中激活 N-羟基马兜铃内酰胺。在 3.5-10 kDa 范围内去除低分子量反应物可使马兜铃内酰胺-DNA 的形成抑制 500 倍，这不能通过添加 SULTs 和 NATs 的辅助因子来预防。总之，我们的结果表明，N-羟基马兜铃内酰胺的遗传毒性取决于细胞类型，不仅涉及磺化，还涉及 N,O-乙酰化和另一种未知的机制。环境。分子突变。2019.©2019 年 Wiley Periodicals，Inc.
