Project description:Exposure to TCDD early in development produces reproductive abnormalities and decreased reproductive capacity in males in subsequent generations We used microarrays to investigate the global programme of gene expression in testicular tissue and identified distinct multigenerational and transgenerational gene expression changes due to legacy TCDD exposure in males.
Project description:Exposure to TCDD early in development produces reproductive abnormalities and decreased reproductive capacity in males in subsequent generations. We used WGBS to investigate differential methylation in testicular tissue and identified distinct multigenerational and transgenerational methylation changes due to legacy TCDD exposure in males.
Project description:Exposure to TCDD early in development produces reproductive abnormalities in adulthood and decreased reproductive capacity in males We used microarrays to investigate the global programme of gene expression in testicular tissue and identified distinct gene expression changes due to TCDD exposure in males.
Project description:Environmental compounds can promote epigenetic transgenerational inheritance of adult-onset disease in subsequent generations following ancestral exposure during fetal gonadal sex determination. The current study examined the ability of dioxin (2,3,7,8-tetrachlorodibenzo[p]dioxin, TCDD) to promote epigenetic transgenerational inheritance of disease and DNA methylation epimutations in sperm. Gestating F0 generation females were exposed to dioxin during fetal day 8 to 14 and adult-onset disease was evaluated in F1 and F3 generation rats. The incidences of total disease and multiple disease increased in F1 and F3 generations. Prostate disease, ovarian primordial follicle loss and polycystic ovary disease were increased in F1 generation dioxin lineage. Kidney disease in males, pubertal abnormalities in females, ovarian primordial follicle loss and polycystic ovary disease were increased in F3 generation dioxin lineage animals. Analysis of the F3 generation sperm epigenome identified 50 differentially DNA methylated regions (DMR) in gene promoters. These DMR provide potential epigenetic biomarkers for transgenerational disease and ancestral environmental exposures. Observations demonstrate dioxin exposure of a gestating female promotes epigenetic transgenerational inheritance of adult onset disease and sperm epimutations. Methylated sperm DNA was isolated from rats ancestrally exposed to dioxin (Hip). Three independent samples from the treatment group were obtained. Differential DNA methylation between treatment groups was determined using Nimblegen microarrays. Treated samples were paired with control samples and hybridized together on arrays (Hip1/Cip1, Hip2/Cip2, and Hip3/Cip3), resulting in three arrays for the treatment.
Project description:Environmental compounds can promote epigenetic transgenerational inheritance of adult-onset disease in subsequent generations following ancestral exposure during fetal gonadal sex determination. The current study examined the ability of dioxin (2,3,7,8-tetrachlorodibenzo[p]dioxin, TCDD) to promote epigenetic transgenerational inheritance of disease and DNA methylation epimutations in sperm. Gestating F0 generation females were exposed to dioxin during fetal day 8 to 14 and adult-onset disease was evaluated in F1 and F3 generation rats. The incidences of total disease and multiple disease increased in F1 and F3 generations. Prostate disease, ovarian primordial follicle loss and polycystic ovary disease were increased in F1 generation dioxin lineage. Kidney disease in males, pubertal abnormalities in females, ovarian primordial follicle loss and polycystic ovary disease were increased in F3 generation dioxin lineage animals. Analysis of the F3 generation sperm epigenome identified 50 differentially DNA methylated regions (DMR) in gene promoters. These DMR provide potential epigenetic biomarkers for transgenerational disease and ancestral environmental exposures. Observations demonstrate dioxin exposure of a gestating female promotes epigenetic transgenerational inheritance of adult onset disease and sperm epimutations.
Project description:The current study demonstrates for the first time that exposure of adult male and female mice to TCDD results in significant alterations in a large number of miRNAs in the ovaries and the testes. These findings suggest that environmental contaminants such as TCDD may alter reproductive functions through alterations in the expression of miRNAs. Future studies will focus on whether such miRNA changes also occur in the germ cells which would explain how TCDD exerts transgenerational effects on the reproductive system by regulating epigenetic pathways involving miRNA
Project description:Adult F0 female zebrafish were fed with control diet or diets containing 5-AZA, MeHg or TCDD. After breeding with unexposed males to produce the F1 generation, livers were sampled from the F0 females. F1 generation embryos were unexposed to test chemicals, were sampled, then bred to produce F2 fish, also unexposed to test chemicals. Methylated DNA immunoprecipitation was carried out on liver samples from F0 and F1 and F2 embryos and MeDIP samples were labeled with Cy5 and hybridised to a zebrafish CGI tiling array versus Cy3-labled zebrafish genomic DNA. The objective was to determine DNA methylation changes following chemical exposure and whether these persisted transgenerationally.
Project description:Normal adult zebrafish can completely regenerate lost myocardium following partial amputation of the ventricle apex. We report that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) significantly impairs this regeneration. Adult male zebrafish were injected with vehicle (control) or TCDD (70ng/g, ip) 1 day prior to partial amputation of the ventricle apex. Gross observation and histological analysis of the amputated heart at 21 days postamputation revealed that TCDD-exposed fish had not progressed beyond the initial clot formation stage, whereas the vehicle control fish showed substantial recovery and almost complete resolution of the formed clot. In contrast, hearts that were not surgically wounded showed no signs of TCDD toxicity. Striking features in the TCDD-exposed hearts were the absence of the normal sheath of new tissue enveloping the wound and the absence of intense cell proliferation at the site of the wound. In addition, the patterns of collagen deposition at the wound site were different between the TCDD and vehicle groups. Because the receptor for TCDD is the aryl hydrocarbon receptor ligand-activated transcriptional regulator, we examined the effects of TCDD exposure on gene expression in the ventricle using DNA microarrays. Samples were collected just prior to amputation and at 6h and 7 days postamputation. TCDD-pretreated hearts had dysregulated expression of genes involved in heart function, tissue regeneration, cell growth, and extracellular matrix. Because embryonic, but not adult, hearts are major targets for TCDD-induced cardiotoxicity, we speculate that the need for embryonic-like cells in regeneration is connected with the effects of TCDD in inhibiting the response to wounding.
Project description:Juvenile zebrafish were fed Biodiet starter (4% body weight per day) for 42 d with TCDD added at 0 ppb, 0.1 ppb, 1 ppb, 10 ppb or 100 ppb. Fish were collected, sexed, weighed and length measured at 0, 7, 14, 28 or 42 d for TCDD assessment, histopathologic and microarray analysis. Microarray experiments were conducted in TCDD-treated (at 0, 0.1, 1, 10 and 100 ppb) for male and female sexed zebrafish at 28 d. NimbleGen Gene Expression 12X135K zebrafish microarrays and One-Color DNA labeling Kit (NimbleGen, WI) were used for genome-wide expression analysis of TCDD-treated zebrafish. TCDD accumulated in a dose- and time-dependent manner and 100 ppb TCDD caused TCDD accumulation in female (15.49 ppb) and male (18.04 ppb) fish at 28 d post exposure. TCDD caused multiple lesions in liver, kidney, intestine and ovary of zebrafish and functional dysregulation such as depletion of glycogen in liver, retrobulbar edema, degeneration of neurosensory epithelium, underdevelopment of intestine, and diminution in the fraction of ovarian follicles containing vitellogenic oocytes. Microarray gene expression analysis comparing control to post TCDD diet revealed dysregulated genes located in pathways associated with cardiac necrosis/cell death, cardiac fibrosis, renal necrosis/cell death and liver necrosis/cell death. These baseline toxicological effects provide evidence for the potential biomarkers, mechanisms and pathology of TCDD induced dysregulation.