Abcb4 acts as multixenobiotic transporter and active barrier against chemical uptake in zebrafish (Danio rerio) embryos

BMC Biology

Research Article

Peggy Wellner¹  Mirko Pietsch¹  Nils Klüver¹  Anne-Marie Schmidt¹  Till Luckenbach¹  Kathleen Burkhardt-Medicke²  Stephan Fischer³  Kristin Schirmer⁴ 

[1] Department of Bioanalytical Ecotoxicology, UFZ – Helmholtz Centre for Environmental Research, 04318, Leipzig, Germany;Department of Bioanalytical Ecotoxicology, UFZ – Helmholtz Centre for Environmental Research, 04318, Leipzig, Germany;Institute of Hydrobiology, Dresden University of Technology, 01062, Dresden, Germany;Department of Environmental Toxicology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland;Department of Environmental Systems Sciences, ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092, Zürich, Switzerland;Department of Environmental Toxicology, Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland;Department of Environmental Systems Sciences, ETH Zürich, Institute of Biogeochemistry and Pollutant Dynamics, 8092, Zürich, Switzerland;Laboratory of Environmental Toxicology, EPF Lausanne, School of Architecture, Civil and Environmental Engineering, 1015, Lausanne, Switzerland;

关键词: Abcb4;    Abcb5;    Chemosensitization;    Efflux transporters;    Environment-tissue barrier;    Multixenobiotic resistance;    MXR;    P-glycoprotein;   

DOI  :  10.1186/1741-7007-11-69

 received in 2013-04-23, accepted in 2013-06-07,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundIn mammals, ABCB1 constitutes a cellular “first line of defense” against a wide array of chemicals and drugs conferring cellular multidrug or multixenobiotic resistance (MDR/MXR). We tested the hypothesis that an ABCB1 ortholog serves as protection for the sensitive developmental processes in zebrafish embryos against adverse compounds dissolved in the water.ResultsIndication for ABCB1-type efflux counteracting the accumulation of chemicals in zebrafish embryos comes from experiments with fluorescent and toxic transporter substrates and inhibitors. With inhibitors present, levels of fluorescent dyes in embryo tissue and sensitivity of embryos to toxic substrates were generally elevated. We verified two predicted sequences from zebrafish, previously annotated as abcb1, by cloning; our synteny analyses, however, identified them as abcb4 and abcb5, respectively. The abcb1 gene is absent in the zebrafish genome and we explored whether instead Abcb4 and/or Abcb5 show toxicant defense properties. Quantitative real-time polymerase chain reaction (qPCR) analyses showed the presence of transcripts of both genes throughout the first 48 hours of zebrafish development. Similar to transporter inhibitors, morpholino knock-down of Abcb4 increased accumulation of fluorescent substrates in embryo tissue and sensitivity of embryos toward toxic compounds. In contrast, morpholino knock-down of Abcb5 did not exert this effect. ATPase assays with recombinant protein obtained with the baculovirus expression system confirmed that dye and toxic compounds act as substrates of zebrafish Abcb4 and inhibitors block its function. The compounds tested comprised model substrates of human ABCB1, namely the fluorescent dyes rhodamine B and calcein-am and the toxic compounds vinblastine, vincristine and doxorubicin; cyclosporin A, PSC833, MK571 and verapamil were applied as inhibitors. Additionally, tests were performed with ecotoxicologically relevant compounds: phenanthrene (a polycyclic aromatic hydrocarbon) and galaxolide and tonalide (two polycyclic musks).ConclusionsWe show that zebrafish Abcb4 is a cellular toxicant transporter and provides protection of embryos against toxic chemicals dissolved in the water. Zebrafish Abcb4 thus is functionally similar to mammalian ABCB1, but differs from mammalian ABCB4, which is not involved in cellular resistance to chemicals but specifically transports phospholipids in the liver. Our data have important implications: Abcb4 could affect bioavailability - and thus toxicologic and pharmacologic potency - of chemicals to zebrafish embryos and inhibition of Abcb4 therefore causes chemosensitization, that is, enhanced sensitivity of embryos to toxicants. These aspects should be considered in (eco)toxicologic and pharmacologic chemical screens with the zebrafish embryo, a major vertebrate model.

【 授权许可】

Unknown   
© Fischer et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.