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.

中文翻译：

---

N-羟基马兜铃内酰胺的生物激活机制：马兜铃酸的硝基还原代谢产物。

马兜铃酸（AAs）是人类肾毒素和致癌物，存在于全世界传统医学实践中所用的马兜铃植物混合物中。AA的基因毒性与代谢酶催化的活性物种的形成有关，其全部组成未知。最近，我们提供了证据表明磺化对AA的生物活化很重要。在这里，我们使用鼠伤寒沙门氏菌umu测试株来表达人类N-乙酰基转移酶（NATs）和磺基转移酶（SULTs），以研究缀合反应在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的代谢产物。两种N-羟基马兜铃内酰胺在表达人NAT1和NAT2的umu菌株中均显示出比亲本菌株更强的遗传毒性作用。另外，AL-I-NOH在表达人SULT1A1和SULT1A2的菌株中显示出更高的遗传毒性，而AL-II-NOH在SULT1A1 / 2和SULT1A3菌株中显示出更高的遗传毒性。2，6-二氯-4-硝基苯酚，SULTs抑制剂，降低了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有诱变作用，表明其他机制可能有助于其遗传毒性。因此，使用推定的SULT底物和抑制剂，我们发现从人肾脏HK-2细胞获得的胞质溶胶在SULTs的参与有限的情况下激活了马兜铃内酯DNA加合物中的N-羟基马兜铃内酰胺。去除3.5-10 kDa范围内的低分子量反应物可将马兜铃内酰胺DNA的形成抑制500倍，通过为SULT和NAT添加辅助因子无法避免这种情况。总之，我们的结果表明，N-羟基马兜铃内酰胺类的遗传毒性取决于细胞类型，不仅涉及磺化作用，还涉及N，O-乙酰基转移以及其他未知机制。环境。大声笑 诱变剂。2019.©2019 Wiley Periodicals，Inc.