title: Toxicogenomic responses of the model organism Caenorhabditis elegans to gold nanoparticles.
abstract: We used Au nanoparticles (Au-NPs) as a model for studying particle-specific effects of manufactured nanomaterials (MNMs) by examining the toxicogenomic responses in a model soil organism,  Caenorhabditis elegans . Global genome expression for nematodes exposed to 4-nm citrate-coated Au-NPs at the LC(10) level (5.9 mg·L(-1)) revealed significant differential expression of 797 genes. The levels of expression for five genes (apl-1, dyn-1, act-5, abu-11, and hsp-4) were confirmed independently with qRT-PCR. Seven common biological pathways associated with 38 of these genes were identified. Up-regulation of 26 pqn/abu genes from noncanonical unfolded protein response (UPR) pathway and molecular chaperones (hsp-16.1, hsp-70, hsp-3, and hsp-4) were observed and are likely indicative of endoplasmic reticulum stress. Significant increase in sensitivity to Au-NPs in a mutant from noncanonical UPR (pqn-5) suggests possible involvement of the genes from this pathway in a protective mechanism against Au-NPs. Significant responses to Au-NPs in endocytosis mutants (chc-1 and rme-2) provide evidence for endocytosis pathway being induced by Au-NPs. These results demonstrate that Au-NPs are bioavailable and cause adverse effects to  C. elegans  by activating both general and specific biological pathways. The experiments with mutants further support involvement of several of these pathways in Au-NP toxicity and/or detoxification.
authors.affiliation: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, United States. olga.tsyusko@uky.edu
authors.forename: Olga V
authors.initials: OV
authors.lastname: Tsyusko
authors.forename: Jason M
authors.initials: JM
authors.lastname: Unrine
authors.forename: David
authors.initials: D
authors.lastname: Spurgeon
authors.forename: Eric
authors.initials: E
authors.lastname: Blalock
authors.forename: Daniel
authors.initials: D
authors.lastname: Starnes
authors.forename: Michael
authors.initials: M
authors.lastname: Tseng
authors.forename: Greg
authors.initials: G
authors.lastname: Joice
authors.forename: Paul M
authors.initials: PM
authors.lastname: Bertsch
mesh_terms: D000682:Amyloid / Q000187:drug effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000235:genetics*; D002951:Citrates / Q000494:pharmacology; D030541:Databases, Genetic; D004705:Endocytosis / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D017238:Genes, Helminth / Q000235:genetics; D006046:Gold / Q000633:toxicity*; D053768:Metal Nanoparticles / Q000633:toxicity*; D023421:Models, Animal; D009154:Mutation / Q000235:genetics; D009336:Necrosis; D020411:Oligonucleotide Array Sequence Analysis; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016019:Survival Analysis; D043922:Toxicogenetics / Q000379:methods*; D056811:Unfolded Protein Response / Q000187:drug effects / Q000235:genetics
chemical_list: D000682:Amyloid; D002951:Citrates; D006046:Gold