title: Comparative effects of nodularin and microcystin-LR in zebrafish: 1. Uptake by organic anion transporting polypeptide Oatp1d1 (Slco1d1).
abstract: Microcystin-LR (MC-LR) and nodularin are hepatotoxins produced by several cyanobacterial species. Their toxicity is based on active cellular uptake and subsequent inhibition of protein phosphatases PP1/2A, leading to hyperphosphorylation and cell death. To date, uptake of MC-LR and nodularin in fish is poorly understood. Here, we investigated the role of the organic anion transporting polypeptide Oatp1d1 in zebrafish (drOatp1d1, Slco1d1) in cellular uptake in zebrafish. We stably transfected CHO and HEK293 cell lines expressing drOatp1d1. In both transfectants, uptake of MC-LR and nodularin was demonstrated by competitive inhibition of uptake with fluorescent substrate lucifer yellow. Direct uptake of MC-LR was demonstrated by immunostaining, and indirectly by the high cytotoxicity in stable transfectants. By means of a synthesized fluorescent labeled MC-LR derivative, direct uptake was further confirmed in HEK293 cells expressing drOatp1d1. Additionally, uptake and toxicity was investigated in the permanent zebrafish liver cell line ZFL. These cells had only a low relative abundance of drOatp1d1, drOatp2b1 and drOatp1f transcripts, which correlated with the lack of MC-LR induced cytotoxicity and transcriptional changes of genes indicative of endoplasmic reticulum stress, a known effect of this toxin. Our study demonstrates that drOatp1d1 functions as an uptake transporter for both MC-LR and nodularin in zebrafish.
authors.affiliation: University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland; University of Zürich, Institute of Plant Biology, Limnological Station, Seestrasse 187, 8802 Kilchberg, Switzerland.
authors.forename: Susanne
authors.initials: S
authors.lastname: Faltermann
authors.affiliation: University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland.
authors.forename: René
authors.initials: R
authors.lastname: Prétôt
authors.affiliation: University of Zürich, Institute of Plant Biology, Limnological Station, Seestrasse 187, 8802 Kilchberg, Switzerland.
authors.forename: Jakob
authors.initials: J
authors.lastname: Pernthaler
authors.affiliation: University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz, Switzerland; Swiss Federal Institute of Technology (ETHZ), Department of Environmental System Sciences, Institute of Biogeochemistry and Pollution Dynamics, Universitätsstrasse 16, 8092 Zürich, Switzerland. Electronic address: karl.fent@fhnw.ch.
authors.forename: Karl
authors.initials: K
authors.lastname: Fent
mesh_terms: D000818:Animals; D000458:Cyanobacteria / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008387:Marine Toxins; D052998:Microcystins / Q000378:metabolism* / Q000633:toxicity; D027361:Organic Anion Transporters / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000378:metabolism* / Q000633:toxicity; D014162:Transfection; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity; D015027:Zebrafish / Q000378:metabolism / Q000502:physiology*
chemical_list: D008387:Marine Toxins; D052998:Microcystins; D027361:Organic Anion Transporters; D010456:Peptides, Cyclic; D014874:Water Pollutants, Chemical; C063998:nodularin; C057862:cyanoginosin LR
keywords: Cellular effects; Cyanobacterial toxin; Microcystin; Nodularin; Oatp1d1; Organic anion uptake transporting polypeptide; Uptake transporters; Zebrafish