Project description:Purpose: The goal of this study was to perform an expression transcript profile over a timecourse of human preadipocytes that were treated with PCB126; Methods: Immortal human preadipocytes (NPAD) were treated with 10 uM PCB126 for 9 hrs, 1 day, or 3 days. RNA was extracted with TriZol, DNase treated, and purified using a Qiagen column. RNAseq was used to assess gene expression. Bioinformatic analyses were used to determine differential gene expression between PCB126 treated and vehicle-treated at the same timepoint.
Project description:This study investigates the effects of the aryl hydrocarbon receptor (AhR) ligands TCDD, PCB126 and PeCDF; the non-AhR ligand PCB153 and the binary mixture PCB126/PCB153 on hepatic gene expression in female sprague dawley rats. Rats were treated with toxicological equivalent doses of TCDD (100ng/kg), PeCDF (200ng/kg), PCB126 (1000ng/kg) and PCB153 (1000ug/kg) 5 days a week for 13 weeks. Experiment Overall Design: There are 6 control chips and representing animals treated with vehicle control. There are 3 biological replicates (3 chips) for each treatment group (eg. TCDD, PCB126), each biological replicate is derived from 2 individual animals. A total of 21 chips were analyzed. Intensities were normalized using the GC-Robust Multiarray (GCRMA) method through Genetraffic software package.
Project description:This study investigates the effects of the aryl hydrocarbon receptor (AhR) ligands TCDD, PCB126 and PeCDF; the non-AhR ligand PCB153 and the binary mixture PCB126/PCB153 on hepatic gene expression in female sprague dawley rats. Rats were treated with toxicological equivalent doses of TCDD (100ng/kg), PeCDF (200ng/kg), PCB126 (1000ng/kg) and PCB153 (1000ug/kg) 5 days a week for 13 weeks. Keywords: Environmental pollutant toxicity comparison
Project description:Polychlorinated biphenyls (PCBs) are ubiquitous and representative pollutants that pose great health risks. While cells' responses to dioxin-like PCBs tend to be studied on a bulk scale, few studies have been made from a single-cell level. Here, by using single-cell RNA sequencing, we depicted a detailed landscape of hepatic nonparenchymal cells' intricate responses to PCB126 exposure. A total of 13 clusters were identified. Notably, PCB126 exposure resulted in cell-type-specific gene expression profiles and genetic pathways. By analyzing genes related to aryl hydrocarbon receptors, we discovered that PCB126 induced the canonical genomic AhR pathway mainly in endothelial cells. In contrast, other cell types showed little induction. Enrichment pathway analysis indicated that immune cells changed their transcriptional patterns in response to PCB126. ScRNA-seq is a powerful tool to dissect underlying mechanisms of chemical toxicity regarding biological heterogeneity. Taken together, our study not only extends our current understanding of PCB126 toxicity, but also emphasizes the importance of in vivo cell heterogeneity in environmental toxicology.
Project description:We performed bulk RNA-sequencing on primary human preadipocytes in which we induced differentiation, and collected samples at 6 timepoints across 14 days. The purpose of our study was to study gene expression during the course of preadipocyte differentiation into adipocytes.
Project description:Exposure to polychlorinated biphenyls (PCBs) has been associated with liver injury in human cohorts and with nonalcoholic steatohepatitis (NASH) in mice fed a high fat diet (HFD). N(6)-methyladenosine (m6A) modification of mRNA regulates transcript fate, but the contribution of m6A modification on regulation of transcription in PCB-induced steatosis and fibrosis is unknown. This study tested the hypothesis that PCB and HFD exposure alters the levels of m6A modification in transcripts that play a role in NASH in vivo. Male C57Bl6/J mice were fed a HFD (12 wks.) and administered a single oral dose of Aroclor1260, PCB126, or Aroclor1260 + PCB126. Genome-wide identification of m6A peaks was accomplished by m6A mRNA immunoprecipitation sequencing (m6A-RIP) and the mRNA transcriptome identified by RNA-seq. Exposure of HFD-fed mice to Aroclor1260 decreased the number of m6A peaks and m6A-containing genes relative to HFD control whereas PCB126 or the combination of Aroclor1260+PCB126 increased m6A modification frequency. ~ 41% of genes had one m6A peak and ~49% had 2-4 m6A peaks. 117 m6A peaks were common in the four experimental groups. The Aroclor1260 + PCB126 exposure group showed the highest number (52) of m6A-peaks. qRT-PCR confirmed enrichment of m6A-containing fragments of the Apob transcript with PCB exposure. Integrated analysis of m6A-RIP-seq and mRNA-seq identified 242 differentially expressed genes (DEGs) with increased or reduced number of m6A peaks. Comparative pathway analysis identified “Immune response: IL-6-induced acute-phase response in hepatocytes” in the Aroclor1260 + PCB126 samples, consistent with steatohepatitis in human PCB epidemiological studies. These data show that PCB exposure in HFD-fed mice alters the m6A landscape offering an additional layer of regulation of gene expression affecting a subset of gene responses in NASH.
Project description:Background: Environmental pollutants, including polychlorinated biphenyls (PCBs) have been shown to alter and promote the development of alcohol-associated liver disease (ALD). Our group recently demonstrated that PCB126 promoted steatosis, hepatomegaly, and modulated intermediary metabolism in an ALD rodent model. Objectives: To better understand how PCB126 promoted ALD, the current study adopts transcriptomic and metallomic approaches to identify mechanistic pathways involved in this promotion. Methods: Briefly, male C57BL/6J mice were exposed to 0.2 mg/kg PCB126 or corn oil vehicle prior to ethanol feeding in the chronic-binge model. Liver tissues were collected for RNA sequencing and ICP-MS metals quantification. Results: PCB126 uniquely modified the transcriptome in EtOH-fed mice in terms of variance. EtOH feeding alone resulting in >4000 differentially expressed genes (DEGs) and PCB126 exposure resulted in more DEGs in the EtOH-fed group over the pair-fed group. Top gene ontology (GO) biological processes indicated ‘peptidyl tyrosine modifications’ and GO molecular function processes showed a loss of ‘metal, and ion, and zinc binding’. Western blot analysis depicted that the JAK2-STAT5 signaling axis was disrupted by the enhanced loss of phosphorylated JAK2 in EtOH+PCB126 mice. Quantified liver essential metal levels were overall depleted by EtOH feeding, and potassium, magnesium, cobalt, and zinc were further decreased by PCB126. Discussion: The results suggests that phosphorylation and metal binding are disrupted in EtOH+PCB126 mice, implying that evolutionarily conserved homeostatic signaling mechanisms are modified by pollutant exposure in EtOH-fed mice. The loss of phosphorylation and essential metals are two suggestive modes of action that may explain the promotion of disease by PCB126 in ALD.
Project description:Chemical modifications of proteins, DNA and RNA moieties play critical roles in regulating gene expression. Emerging evidence suggests these RNA modifications (epitranscriptomics) have substantive roles in basic biological processes. One of the most common modifications in mRNA and noncoding RNAs is N6-methyladenosine (m6A). In a subset of mammalian mRNAs, m6A sites are preferentially enriched near stop codons, in 3′ UTRs, and within exons, suggesting an important role in the regulation of mRNA processing and function including alternative splicing and gene expression. Very little is known about the effect of environmental chemical exposure on m6A modifications. As many of the commonly occurring environmental contaminants alter gene expression profiles and have detrimental effects on physiological processes, it is important to understand the effects of exposure on this important layer of gene regulation. Hence, the objective of this study was to characterize the acute effects of developmental exposure to PCB126, an environmentally relevant dioxin-like PCB, on m6A methylation patterns. We exposed zebrafish embryos to PCB126 for 6 hours starting from 72 hours post-fertilization and profiled m6A RNA using methylated RNA immunoprecipitation followed by sequencing (MeRIP-seq), as well as assessing changes in mRNA splicing. We observed several hundreds of peaks that are differentially expressed in response to PCB126 exposure (FDR 5%). The majority of the peaks are preferentially located around the 3’UTR and stop codons. Pathway analysis of m6A marked transcripts induced by PCB126 exposure revealed that these transcripts are associated with important developmental pathways (MAPK, Hedgehog, Notch and Wnt). These results suggest that PCB126 could affect developmental gene expression patterns by altering m6A levels. Gene expression analysis revealed upregulation of classical aryl hydrocarbon receptor (AHR) target genes such as cytochrome P450s in response to PCB126 exposure. Interestingly, none of the AHR target genes overlapped with the m6A altered transcripts, suggesting that xenobiotic metabolism may not be under m6A regulation. Further studies are necessary to understand the functional consequences of exposure-associated alterations in m6A levels. This work is supported by NIEHS ES024915.