Integrated approaches to investigate the effect of progestins in fish and their occurrence in the aquatic environment

Abstract : To date, most studies on endocrine disrupting compounds have focused on estrogenic ones with a particular attention to natural (estradiol, estrone, estriol) and synthetic estrogens (17α-ethinylestradiol). However, there are now emerging evidences on the occurrence of other natural and synthetic steroids in aquatic systems. Among them, the potential risk on aquatic species posed by synthetic progestins, widely used as oral contraceptive and hormone replacement therapy, has been recently pointed out. However, their occurrence, fate and effects have been poorly investigated. In the present study, we used an integrated approach that combines effect-based tools and chemical analyses i) to investigate the cellular mode of action of a broad range of progestins and their effects in zebrafish, ii) to detect (anti)-progestagenic activities in French aquatic systems, and iii) to identify the compounds responsible for (anti)-progestagenic activities. Twenty-four selected progestins were screened using dedicated reporter gene assays for their capacities to interact with human (h) or zebrafish (zf) nuclear receptors (PR, ER, AR, GR) in vitro and to alter the cell-specific expression of target genes in zebrafish embryos in vivo. By using human reporter cell lines stably expressing either hPR or zfPR, we revealed marked interspecies differences on the ability of progestins to activate/antagonize PRs. We also demonstrated that progestins can interfere with multiple NR signaling pathways in vitro eliciting estrogenic, androgenic and/or (anti)glucorticoid activities, in a species-specific manner. Their capacities to interfere with hormone-regulated genes were further evaluated in vivo in zebrafish. In transgenic cyp19a1b-GFP embryos, progestins derived from 19-nor-testosterone induced estrogenic responses in radial glial cells through an ER-dependent mechanism. Some of them also disrupted GR-signaling pathway in transgenic cyp11c1-GFP larvae. Altogether, our data show complex toxicological profiles of progestins and their capacities to interfere with the biosynthesis of neuro-estrogens and corticosteroids in the developing fish. To assess the potential exposure of aquatic organisms to ligands of the progesterone receptor, a bioanalytical approach was used to detect and quantify progestagenic activities in environmental samples (including wastewater, surface waters and sediments). For the first time, h and zf (anti)progestagenic activities in aquatic samples were reported showing wastewaters as important sources of contamination. Importantly, marked interspecies differences were highlighted between h and zf with noticeable zebrafish-specific PR agonistic activities quantified at several sites. To identify zebrafish-specific PR active compounds at these sites, environmental extracted were fractionated using RP-HPLC and several zfPR- but not hPR-active fractions were isolated, hence confirming fish-specificity. Non-target chemical analysis using LC-Q-TOF in these fractions allowed identification of steroidal structures and pharmaceuticals. Their biological activities on zfPR and hPR will be tested. Overall our project provides an extensive (eco)toxicological characterization of currently used progestin pharmaceuticals on key molecular endocrine targets. It also depicted for the first time (anti)progestagenic activities in aquatic samples showing wastewaters as a source of contamination by zf-active compounds, some of which have been identified. Overall, this study supports the need to further characterize ecotoxicological hazards and risks posed by progestins.
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Conference papers
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Submitted on : Friday, August 3, 2018 - 1:17:54 PM
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  • HAL Id : ineris-01853437, version 1

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François Brion, Selim Ait-Aissa, Olivier Kah, Patrick Balaguer, Hélène Budzinski. Integrated approaches to investigate the effect of progestins in fish and their occurrence in the aquatic environment. NORMAN Workshop "Integrated Exposure and Effects Assessment", Apr 2017, Amsterdam, Netherlands. ⟨ineris-01853437⟩

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