title: Novel Cadmium Responsive MicroRNAs in Daphnia pulex.
abstract: Daphnia pulex is a widely used toxicological model and is known for its sensitivity to cadmium (Cd). Recent research suggests that microRNAs (miRNAs) play a critical role in animal responses to heavy metals. To investigate the functions of D. pulex miRNAs under Cd exposure, we analyzed the miRNA profiles of D. pulex after 48 h using miRNA microarrays and validated our findings by q-PCR. miRNA dpu-let-7 was identified as a stably expressed gene and used as a reference. We identified 22 and 21 differentially expressed miRNAs under low (20 μg/L CdCl2) and high-exposure (40 μg/L CdCl2) concentrations compared to controls, respectively. Cellular functions of predicted miRNA target Cd-responsive genes included oxidative stress, ion transport, mitochondrial damage, and DNA repair. An insulin-related network was also identified in relation to several Cd-responsive miRNAs. The expression of three predicted target genes for miR-71 and miR-210 were evaluated, and expression of two of them (SCN2A and SLC31A1) was negatively correlated with the expression of their regulator miRNAs. We show miR-210 is hypoxia-responsive in D. pulex and propose Cd and hypoxia induce miR-210 via a same HIF1α modulated pathway. Collectively, this research advances our understanding on the role of miRNAs in response to heavy-metal exposure.
authors.affiliation: Department of Forestry and Natural Resources, Purdue University , West Lafayette, Indiana, 47907 United States.
authors.forename: Shuai
authors.initials: S
authors.lastname: Chen
authors.affiliation: School of Aquatic and Fishery Sciences, University of Washington , Seattle, Washington, 98195 United States.
authors.forename: Garrett J
authors.initials: GJ
authors.lastname: McKinney
authors.affiliation: Department of Forestry and Natural Resources, Purdue University , West Lafayette, Indiana, 47907 United States.|Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Ocean and Atmospheric Administration , Seattle, Washington, 98112 United States.
authors.forename: Krista M
authors.initials: KM
authors.lastname: Nichols
authors.affiliation: Environmental Genomics Group, School of Biosciences, University of Birmingham , Edgbaston, Birmingham B15 2TT, U.K.
authors.forename: John K
authors.initials: JK
authors.lastname: Colbourne
authors.affiliation: Department of Forestry and Natural Resources, Purdue University , West Lafayette, Indiana, 47907 United States.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Sepúlveda
mesh_terms: D000818:Animals; D002104:Cadmium / Q000008:administration & dosage / Q000633:toxicity*; D027682:Cation Transport Proteins / Q000235:genetics; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics; D003621:Daphnia / Q000187:drug effects* / Q000235:genetics*; D054750:Ecotoxicology / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects; D000860:Hypoxia / Q000235:genetics; D007328:Insulin / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics*; D062551:NAV1.2 Voltage-Gated Sodium Channel / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D015203:Reproducibility of Results
chemical_list: D027682:Cation Transport Proteins; D007328:Insulin; D035683:MicroRNAs; D062551:NAV1.2 Voltage-Gated Sodium Channel; D002104:Cadmium