Boonprasert Kanyarat, Satarug Soisungwan, Morais Christudas, Gobe Glenda C, Johnson David W, Na-Bangchang Kesara, Vesey David A
Chulabhorn International College of Medicine, Thammasat University, Pathumthani, Thailand; Centre for Kidney Disease Research, The University of Queensland School of Medicine, Translational Research Institute, Brisbane, Australia.
Centre for Kidney Disease Research, The University of Queensland School of Medicine, Translational Research Institute, Brisbane, Australia.
Toxicol Lett. 2016 May 13;249:5-14. doi: 10.1016/j.toxlet.2016.02.016. Epub 2016 Mar 19.
Enzymes of the cytochrome P450 (CYP) super-family are implicated in cadmium (Cd) -induced nephrotoxicity, however, direct evidence is lacking. This study investigated the endogenous expression of various CYP proteins together with the stress-response proteins, heme oxygenase-1 (HO-1) and metallothionein (MT) in human kidney sections and in cadmium-exposed primary cultures of human proximal tubular epithelial cells (PTC). By immunohistochemistry, the CYP members 2B6, 4A11 and 4F2 were prominently expressed in the cortical proximal tubular cells and to a lesser extent in distal tubular cells. Low levels of CYPs 2E1 and 3A4 were also detected. In PTC, in the absence of Cd, CYP2E1, CYP3A4, CYP4F2 and MT were expressed, but HO-1, CYP2B6 and CYP4A11 were not detected. A range of cadmium concentrations (0-100μM) were utilized to induce stress conditions. MT protein was further induced by as little as 0.5μM cadmium, reaching a 6-fold induction at 20μM, whereas for HO-1, a 5μM cadmium concentration was required for initial induction and at 20μM cadmium reached a 15-fold induction. The expression of CYP2E1, CYP3A4, and CYP4F2 were not altered by any cadmium concentrations tested at 48h. Cadmium caused a reduction in cell viability at concentrations above 10μM. In conclusion although cultured PTC, do express CYP proteins, (CYP2E1, CYP3A4, and CYP4F2), Cd-induced cell stress as indicted by induction of HO-1 and MT does not alter expression of these CYP proteins at 48h.
细胞色素P450（CYP）超家族的酶与镉（Cd）诱导的肾毒性有关，然而，缺乏直接证据。本研究调查了人肾切片以及镉暴露的人近端肾小管上皮细胞（PTC）原代培养物中各种CYP蛋白以及应激反应蛋白血红素加氧酶-1（HO-1）和金属硫蛋白（MT）的内源性表达。通过免疫组织化学，CYP成员2B6、4A11和4F2在皮质近端肾小管细胞中显著表达，在远端肾小管细胞中表达程度较低。也检测到了低水平的CYP 2E1和3A4。在PTC中，在没有镉的情况下，CYP2E1、CYP3A4、CYP4F2和MT表达，但未检测到HO-1、CYP2B6和CYP4A11。使用一系列镉浓度（0 - 100μM）来诱导应激条件。低至0.5μM的镉即可进一步诱导MT蛋白，在20μM时达到6倍诱导，而对于HO-1，初始诱导需要5μM的镉浓度，在20μM镉时达到15倍诱导。在48小时时，所测试的任何镉浓度均未改变CYP2E1、CYP3A4和CYP4F2的表达。镉在浓度高于10μM时会导致细胞活力降低。总之，虽然培养的PTC确实表达CYP蛋白（CYP2E1、CYP3A4和CYP4F2），但HO-1和MT的诱导所表明的镉诱导的细胞应激在48小时时不会改变这些CYP蛋白的表达。
