title: Molecular mechanisms of toxicity of silver nanoparticles in zebrafish embryos.
abstract: Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk-, and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24 h of exposure, but with a recovery at 48 h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24 h, but not at 48 h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms.
authors.affiliation: Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK. r.van-aerle@exeter.ac.uk
authors.forename: Ronny
authors.initials: R
authors.lastname: van Aerle
authors.forename: Anke
authors.initials: A
authors.lastname: Lange
authors.forename: Alex
authors.initials: A
authors.lastname: Moorhouse
authors.forename: Konrad
authors.initials: K
authors.lastname: Paszkiewicz
authors.forename: Katie
authors.initials: K
authors.lastname: Ball
authors.forename: Blair D
authors.initials: BD
authors.lastname: Johnston
authors.forename: Eliane
authors.initials: E
authors.lastname: de-Bastos
authors.forename: Timothy
authors.initials: T
authors.lastname: Booth
authors.forename: Charles R
authors.initials: CR
authors.lastname: Tyler
authors.forename: Eduarda M
authors.initials: EM
authors.lastname: Santos
mesh_terms: D000818:Animals; D053768:Metal Nanoparticles / Q000633:toxicity*; D012834:Silver / Q000737:chemistry*; D015027:Zebrafish / Q000196:embryology*
chemical_list: D012834:Silver