Mao Baiping, Wu Chengyun, Zheng Wenwen, Shen Qiuxia, Wang Yiyan, Wang Qiufan, Lin Han, Li Xiaoheng, Sun Jianliang, Ge Ren-Shan
Department of Anesthesiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, China.
Department of Respiratory Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, China.
Neurosci Lett. 2018 Sep 25;684:169-174. doi: 10.1016/j.neulet.2018.08.008. Epub 2018 Aug 11.
Methoxychlor is primarily used as an insecticide and it is widely present in the environment. The objective of the present study was to investigate the direct effects of methoxychlor and its metabolite hydroxychlor (HPTE) on rat neurosteroidogenic 3α-hydroxysteroid dehydrogenase (AKR1C14) and retinol dehydrogenase 2 (RDH2) activities. Rat AKR1C14 and RDH2 were cloned and expressed in COS-1 cells, and the effects of methoxychlor and HPTE on these enzymes were measured. HPTE was more potent to inhibit AKR1C14 and RDH2 activities than methoxychlor, with IC values of 2.602 ± 0.057 μM and 20.473 ± 0.049 μM, respectively, while those of methoxychlor were over 100 μM. HPTE competitively inhibited AKR1C14 and RDH2 when steroid substrates were used, while it showed a mode of mixed inhibition on these enzymes when NADPH/NAD were used. We elucidated the binding mode of methoxychlor and HPTE to the crystal structure of AKR1C14 by molecular docking and found that HPTE had higher affinity with the enzyme than methoxychlor. In conclusion, HPTE is more potent than methoxychlor to inhibit both AKR1C14 and RDH2.
甲氧滴滴涕主要用作杀虫剂，在环境中广泛存在。本研究的目的是调查甲氧滴滴涕及其代谢物羟基氯（HPTE）对大鼠神经甾体生成3α-羟基类固醇脱氢酶（AKR1C14）和视黄醇脱氢酶2（RDH2）活性的直接影响。将大鼠AKR1C14和RDH2克隆并在COS-1细胞中表达，并测定甲氧滴滴涕和HPTE对这些酶的影响。HPTE比甲氧滴滴涕更有效地抑制AKR1C14和RDH2的活性，其IC值分别为2.602±0.057μM和20.473±0.049μM，而甲氧滴滴涕的IC值超过100μM。当使用甾体底物时，HPTE竞争性抑制AKR1C14和RDH2，而当使用NADPH/NAD时，它对这些酶表现出混合抑制模式。我们通过分子对接阐明了甲氧滴滴涕和HPTE与AKR1C14晶体结构的结合模式，发现HPTE与该酶的亲和力比甲氧滴滴涕更高。总之，HPTE比甲氧滴滴涕更有效地抑制AKR1C14和RDH2。
