title: Stimulatory effects of combined endocrine disruptors on MA-10 Leydig cell steroid production and lipid homeostasis.
abstract: Previous work in our laboratory demonstrated that in-utero exposure to a mixture of the phytoestrogen Genistein (GEN), and plasticizer DEHP, induces short- and long-term alterations in testicular gene and protein expression different from individual exposures. These studies identified fetal and adult Leydig cells as sensitive targets for low dose endocrine disruptor (ED) mixtures. To further investigate the direct effects and mechanisms of toxicity of GEN and DEHP, MA-10 mouse tumor Leydig cells were exposed in-vitro to varying concentrations of GEN and MEHP, the principal bioactive metabolite of DEHP. Combined 10μM GEN+10μM MEHP had a stimulatory effect on basal progesterone production. Consistent with increased androgenicity, the mRNA of steroidogenic and cholesterol mediators Star, Cyp11a, Srb1 and Hsl, as well as upstream orphan nuclear receptors Nr2f2 and Sf1 were all significantly increased uniquely in the mixture treatment group. Insl3, a sensitive marker of Leydig endocrine disruption and cell function, was significantly decreased by combined GEN+MEHP. Lipid analysis by high-performance thin layer chromatography demonstrated the ability of combined 10μM combined GEN+MEHP, but not individual exposures, to increase levels of several neutral lipids and phospholipid classes, indicating a generalized deregulation of lipid homeostasis. Further investigation by qPCR analysis revealed a concomitant increase in cholesterol (Hmgcoa) and phospholipid (Srebp1c, Fasn) mediator mRNAs, suggesting the possible involvement of upstream LXRα agonism. These results suggest a deregulation of MA-10 Leydig function in response to a combination of GEN+MEHP. We propose a working model for GEN+MEHP doses relevant to human exposure involving LXR agonism and activation of other transcription factors. Taken more broadly, this research highlights the importance of assessing the impact of ED mixtures in multiple toxicological models across a range of environmentally relevant doses.
authors.affiliation: The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: Jones
authors.affiliation: The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Boisvert
authors.affiliation: Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada.
authors.forename: Andrada
authors.initials: A
authors.lastname: Naghi
authors.affiliation: Lipid Biology Laboratory, RIKEN Institute, Wakoshi, Saitama, Japan; INSERM UMR1060, University Lyon 1, Villeurbanne, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Hullin-Matsuda
authors.affiliation: Lipid Biology Laboratory, RIKEN Institute, Wakoshi, Saitama, Japan.
authors.forename: Peter
authors.initials: P
authors.lastname: Greimel
authors.affiliation: Lipid Biology Laboratory, RIKEN Institute, Wakoshi, Saitama, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada.
authors.forename: Vassilios
authors.initials: V
authors.lastname: Papadopoulos
authors.affiliation: The Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec, Canada; Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada; Department of Medicine, McGill University, Montreal, Quebec, Canada; Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada. Electronic address: martine.culty@mcgill.ca.
authors.forename: Martine
authors.initials: M
authors.lastname: Culty
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002855:Chromatography, Thin Layer; D004051:Diethylhexyl Phthalate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000008:administration & dosage / Q000633:toxicity*; D019833:Genistein / Q000008:administration & dosage / Q000633:toxicity*; D006706:Homeostasis; D007985:Leydig Cells / Q000187:drug effects* / Q000473:pathology; D050356:Lipid Metabolism / Q000187:drug effects*; D008297:Male; D051379:Mice; D010743:Phospholipids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011374:Progesterone / Q000096:biosynthesis; D013256:Steroids / Q000096:biosynthesis; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D052244:Endocrine Disruptors; D010743:Phospholipids; D013256:Steroids; D014157:Transcription Factors; D011374:Progesterone; D004051:Diethylhexyl Phthalate; D019833:Genistein; C016599:mono-(2-ethylhexyl)phthalate
keywords: Endocrine disruptors; Genistein; Lipids; MA-10 Leydig cells; Phthalate; Steroidogenesis