Project description:DE-71, a commercial mixture of the polybrominated diphenyl ethers (PBDEs), is used as flame retardant and the potential exposure to PBDEs is an emerging public health concern. It has been clarified that long term exposure to PBDEs induces hepatocellular carcinoma in mouse. In this study, we analyzed how DE-71 impacts on DNA methylation in hepatocellular carcinoma.
Project description:Affymetrix high-density oligonucleotide microarray analysis was performed to analyse hydroxylated polybrominated diphenyl ethers (OH-PBDE)-induced gene expression changes in H295R adrenocortical carcinoma cells. Cells were treated with growth medium in the presence or absence of 10 µM 2-OH-BDE47 or 2-OH-BDE85 for 24 hours before the gene expression changes were investigated. Experiment Overall Design: Gene expression changes in response to hydroxylated polybrominated diphenyl ethers (OH-PBDEs) were analysed by Microarray technology in H295R adrenocortical carcinoma cells. Cells were treated with 10 µM of 2-OH-BDE47 or 2-OH-BDE85 (or growth medium alone) for 24 hours before the OH-PBDE-induced gene expression changes were investigated. Control, 2-OH-BDE47- and 2-OH-BDE85-treated samples were collected from three independent experiments each.
Project description:Hornyhead turbot (Pleuronichthys verticalis), a sentinel flatfish species, were intraperitoneally injected with environmentally relevant mixtures of polybrominated diphenyl ethers (PBDEs) or polychlorinated biphenyls (PCBs). After 96 h, fish were sacrificed and liver tissue was collected for gene expression analysis using a custom-designed microarray.
Project description:A Platichthys flesus cDNA microarray (GENIPOL) comprised of 12,700 clones, was used to determine and characterize gene expression profiles of flounders (Platichthys flesus) exposed to polybrominated diphenyl ethers (pentamix).
Project description:Polybrominated diphenyl ethers (PBDEs) are commonly used as flame retardants in a variety of commercial and household products. They have been detected in the environment and accumulate in mammalian tissues and fluids. PBDE toxicity is thought to be associated with endocrine disruption, developmental neurotoxicity and changes in fetal development. Although humans are exposed to PBDEs, our knowledge of the effects of PBDE metabolites on human cells with respect to health risk is insufficient. Two hydroxylated PBDEs (OH-PBDEs), 2-OH-BDE47 and 2-OH-BDE85, were investigated for their effects on cell viability/proliferation, DNA damage, cell cycle distribution and gene expression profiling in H295R adrenocortical carcinoma cells. We show that the two agents are cytotoxic in a dose-dependent manner only at micromolar concentrations, with 2-OH-BDE85 being more toxic than 2-OH-BDE47. However, no DNA damage was observed for either chemical, suggesting that the biological effects of OH-PBDEs occur primarily via non-genotoxic routes. Furthermore, no evidence of aryl hydrocarbon receptor (AHR)-mediated, dioxin-like toxicity was observed. Instead, we report that a micromolar concentration of OH-PBDEs induces transcriptional changes associated with endoplasmic reticulum stress and the unfolded protein response. We discuss whether OH-PBDE bioaccumulation could result in impairment of the adrenocortical secretory function.
Project description:Polybrominated diphenyl ethers (PBDEs) are persistent, highly toxic, and widely distributed environmental pollutants. The microbial populations and functional reductive dehalogenases (RDases) responsible for PBDEs debromination in anoxic systems remain poorly understood, which confounds bioremediation of PBDE-contaminated sites. Here we report a PBDE-debrominating enrichment culture dominated by a previously undescribed Dehalococcoides mccartyi population. A D. mccartyi strain, designated TZ50, whose genome contains 25 putative RDase encoding genes was isolated from the debrominating enrichment culture. Strain TZ50 dehalogenated a mixture of penta- and tetra-BDE congeners (total BDEs 1.48 uM) to diphenyl ether within two weeks (0.58 uM Br- /d) via ortho- and meta- bromine elimination; strain TZ50 also dechlorinated tetrachloroethene (PCE) to vinyl chloride and ethene (260.2 M Cl- /d). Native-PAGE, proteomic profiling, and in vitro enzymatic activity assays implicated the involvement of three RDases in PBDEs and PCE dehalogenation. Two RDases, TZ50_0172 (PteATZ50) and TZ50_1083 (TceATZ50), were responsible for debromination of penta- and tetra-BDEs to di-BDE. TZ50_0172 and TZ50_1083 were also implicated in dechlorination of PCE to TCE and of TCE to vinyl chloride/ethene, respectively. The other expressed dehalogenase, TZ50_0090, was associated with debromination of di-BDE to diphenyl ether, but its role in PCE dechlorination was unclear. Comparatively few RDases are known to be involved in PBDE debromination and the identification of PteATZ50, TceATZ50, and TZ50_0090 provides additional information for evaluating debromination potential at contaminated sites. Moreover, the bifunctionality of the PteATZ50 and TceATZ50 in both PBDEs and PCE dehalogenation makes strain TZ50 a suitable candidate for remediation of co-contaminated sites.
Project description:Extensive use of polybrominated diphenyl ethers (PBDEs) has resulted in widespread environmental distribution and concerns remain about risks to human health and ecosystems from legacy PBDE contamination. Though bioremediation has been proven to be a cost-effective and efficient technology for treating halogenated pollutants in situ, application of bioremediation technologies at PBDE-contaminated sites is restricted by a lack of knowledge about functional PBDE-dehalogenating microbes. In the current study, we observed distinct PBDE-dehalogenation activity by three previously isolated Dehalococcoides mccartyi strains (CG1, CG4, and 11a5). PBDE debromination proceeded via distinct pathways in each D. mccartyi strain and involved previously characterized (TceA11a5, PcbA1, and PcbA4) and uncharacterized (11a5_e001) reductive dehalogenases (RDase), suggesting that this phenotype may be more widespread among the Dehalococcoides than is currently recognized.
Project description:Similar to the scRNA-Seq data (GSE125272), a surgical menopausal (ovariectomized) mouse model was used to assess how mammary gland tissue was affected by both 17β-estradiol (E2) and polybrominated diphenyl ethers (PBDEs). The PBDE treatments include three analyzed flame retardants: BDE-47, BDE-100 and BDE-153. Bulk RNA-Seq data was created with treatment conditions lasting 1 week. Gene expression changes for PBDE treatment are relatively small compared to E2 treatment. However, along with other studies and experiments, this data is meant to contribute to greater understanding of the interaction of PBDE exposure and estrogen signaling.
