Project description:Analysis of developmental toxicity of environmental toxin 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) at the level of gene expression. Dams of Wistar rats were exposed to environmentaly relevant doses of BDE-47 at gestation and lactation. Gene expression in total brains and frontal lobes was analysed in offspring on postnatal day 10.
Project description:To develop molecular indicators of neurodevelopmental disorders related to the exposure to external chemicals, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to influence neuronal differentiation from embryonic stem cells. Thalidomide (TMD), bisphenol A (BPA), 4-hydroxy-2,2',3,4',5,5',6-heptachlorobiphenyl (4OH-PCB187) and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) were exposed to human embryonic stem (ES) cell-derived sphere on day 3 after starting sphere formation for 72 hours. Gene expression analysis on the stage of sphere development showed chemical specific characteristics.
Project description:RNA-seq provided a general overview of the gene expression profiles of the digestive glands of Mactra veneriformis exposed to 2, 2′,4,4′-tetrabromodiphenyl ether (BDE-47, a type of widely used brominated flame retardants).
Project description:Toxicity of PBDE for male reproductive system was shown in several human and animal studies, however long lasting effects of perinatal exposures on male reproduction are yet poorly understood. In this study pregnant Wistar rats were exposed to 0.2 mg/kg 2,2’,4,4’-tetrabromodiphenyl ether (BDE-47) from gestation day 8 till postnatal day 21 and testis transcriptome was analyzed on postnatal day 120 in offspring. Exposed animals had significant change in testes transcriptome including suppression of genes essential for spermatogenesis and activation of immune response genes. In particular exposed animals had on average 4 fold decreased expression of protamine and transition protein genes in testes suggesting that histone-protamine exchange may be dysregulated in the course of spermatogenesis resulting in exposure legacy transfer to the next generation via aberrant sperm epigenome.
Project description:Polychlorinated biphenyls (PCBs) are persistent and ubiquitously distributed environmental pollutants. Based on their chemical structure, PCBs are classified into non-ortho substituted and ortho-substituted congeners. Non-ortho-substituted PCBs are structurally similar to dioxin or TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and their mode of action and toxic effects are well established. In contrast, much less is known about the effects of ortho-substituted PCBs. Studies conducted so far have focused on tissue-specific effects but there is limited knowledge about the effects on the whole organism, particularly the sensitive developmental stages in vertebrates. Hence, in this study we investigated the effects of exposure to an environmentally relevant ortho-substituted PCB (2,2’,4,4’,5,5’-hexachlorobiphenyl; PCB153) on zebrafish embryos. We exposed zebrafish embryos to either DMSO (0.1%; solvent control) or three different concentrations of PCB153 (0.1, 1 and 10 μM) from 4 hours post-fertilization (hpf) to 120 hpf. At the end of the exposure, larvae were sampled for determining transcriptional changes (RNA sequencing) and the remaining embryos were maintained in contaminant-free environment. At 7 and 14 days post-fertilization (dpf), zebrafish larvae were assessed for locomotory behavior. We did not observe any overt phenotypes during the exposure period, but observed a spinal phenotype in the 10μM PCB153 treated group starting at 7 dpf. This phenotype was observed in a dose-dependent manner and majority of the embryos with this phenotype died by 14 dpf. RNA sequencing of 5 dpf larvae exposed to PCB153 also revealed dose-dependent changes in gene expression patterns. A total of 633, 2227, and 3378 differentially expressed genes were observed in 0.1, 1 and 10 μM PCB153 treated embryos, respectively. Among these, 301 genes were common to all treatment groups, and KEGG pathway analysis revealed enrichment of genes related to circadian rhythm, FOXO signaling and insulin resistance pathways. We are currently investigating the functions of genes that are uniquely altered by different PCB153 concentrations. Overall, these results suggest that developmental exposure to PCB153, a PCB congener highly prevalent in the environment, targets multiple physiological processes including photoperiod regulation and metabolism. [Funded by NIH P01ES021923 and NSF OCE-1314642].
