Endocrine Disruptors Differentially Target ATP-Binding Cassette Transporters in the Blood-Testis Barrier and Affect Leydig Cell Testosterone Secretion In Vitro
Endocrine Disruptors Differentially Target ATP-Binding Cassette Transporters in the Blood-Testis Barrier and Affect Leydig Cell Testosterone Secretion In Vitro
复制标题
DOI：
10.1093/toxsci/kft198
复制
发表时间：
2013-12-01
影响因子：
3.8
通讯作者：
Masereeuw, Rosalinde
中科院分区：
文献类型：
--
作者：
Dankers, Anita C. A.;Roelofs, Maarke J. E.;Masereeuw, Rosalinde
内分泌干扰物（EDCs）被认为主要通过干扰类固醇激素功能引起睾丸毒性。或者，内分泌干扰物可能通过与血睾屏障中表达的ATP结合盒（ABC）转运蛋白相互作用发挥其作用。在这项研究中，我们研究了双酚A（BPA），四溴双酚A（TBBPA），二（2-乙基己基）邻苯二甲酸酯，单（2-乙基己基）邻苯二甲酸酯，全氟辛酸（PFOA），和全氟辛烷磺酸（PFOS）对乳腺癌耐药蛋白（BCRP），多药耐药蛋白1和4（MRP 1和MRP 4），和P-糖蛋白（P-gp）使用膜囊泡过表达这些转运蛋白的影响。BPA仅抑制BCRP活性，而TBBPA、PFOA和PFOS则抑制所有测试的转运蛋白。未观察到邻苯二甲酸酯的影响。使用转运蛋白过度表达的Madin-Darby犬肾细胞，我们发现BPA和PFOA，但不是TBBPA，通过BCRP转运，而没有一种化合物通过P-gp转运。为了研究这些发现的毒理学意义，在暴露于选定的EDCs后，在小鼠Leydig（MA-10）细胞中测定睾酮分泌和类固醇生成基因的表达。只有BPA和TBBPA浓度依赖性地增加MA-10细胞的睾酮分泌，分别为对照水平的6倍和46倍。MK-571对Mrps的抑制完全阻断了TBBPA引起的睾酮分泌，这不能用类固醇基因表达的一致变化来解释。因此，我们假设转运蛋白介导的睾酮前体流出MA-10细胞被TBBPA抑制，导致睾酮生产的可用性更高。我们的数据显示了ABC转运蛋白在与睾丸毒性相关的EDC风险评估中的毒理学和临床相关性。
Endocrine-disrupting chemicals (EDCs) are considered to cause testicular toxicity primarily via interference with steroid hormone function. Alternatively, EDCs could possibly exert their effects by interaction with ATP-binding cassette (ABC) transporters that are expressed in the blood-testis barrier. In this study, we investigated the effects of bisphenol A (BPA), tetrabromobisphenol A (TBBPA), bis(2-ethylhexyl) phthalate, mono(2-ethylhexyl) phthalate, perfluorooctanoic acid (PFOA), and perfluorooctanesulfonic acid (PFOS) on breast cancer resistance protein (BCRP), multidrug resistance proteins 1 and 4 (MRP1 and MRP4), and P-glycoprotein (P-gp) using membrane vesicles overexpressing these transporters. BPA solely inhibited BCRP activity, whereas TBBPA, PFOA, and PFOS inhibited all transporters tested. No effect was observed for the phthalates. Using transporter-overexpressing Madin-Darby canine kidney cells, we show that BPA and PFOA, but not TBBPA, are transported by BCRP, whereas none of the compounds were transported by P-gp. To investigate the toxicological implications of these findings, testosterone secretion and expression of steroidogenic genes were determined in murine Leydig (MA-10) cells upon exposure to the selected EDCs. Only BPA and TBBPA concentration dependently increased testosterone secretion by MA-10 cells to 6- and 46-fold of control levels, respectively. Inhibition of the Mrps by MK-571 completely blocked testosterone secretion elicited by TBBPA, which could not be explained by coinciding changes in expression of steroidogenic genes. Therefore, we hypothesize that transporter-mediated efflux of testosterone precursors out of MA-10 cells is inhibited by TBBPA resulting in higher availability for testosterone production. Our data show the toxicological and clinical relevance of ABC transporters in EDC risk assessment related to testicular toxicity.