Determining mechanism-based biomarkers that distinguish adaptive and adverse cellular processes is critical to understanding the health effects of environmental exposures. Shifting from in vivo, low-throughput toxicity studies to high-throughput screening (HTS) paradigms and risk assessment based on in vitro and in silico testing requires utilizing toxicity pathway information to distinguish adverse outcomes from recoverable adaptive events. Little work has focused on oxidative stresses in human airway for the purposes of predicting adverse responses. We hypothesize that early gene expression-mediated molecular changes could be used to delineate adaptive and adverse responses to environmentally-based perturbations. Here, we examined cellular responses of the tracheobronchial airway to zinc (Zn) exposure, a model oxidant. Airway derived BEAS-2B cells exposed to 210 M Zn2+ elicited concentration- and time-dependent cytotoxicity. Normal, adaptive, and cytotoxic Zn2+ exposure conditions were determined with traditional apical endpoints, and differences in global gene expression around the tipping point of the responses were used to delineate underlying molecular mechanisms. Bioinformatic analyses of differentially expressed genes indicate early enrichment of stress signaling pathways, including those mediated by the transcription factors p53 and NRF2. After 4 h, 154 genes were differentially expressed (p <0.01) between the adaptive and cytotoxic Zn2+ concentrations. Nearly 40% of the biomarker genes were related to the p53 signaling pathway with 30 genes identified as likely direct targets using a database of p53 ChIP-seq studies. Despite similar p53 activation profiles, these data revealed widespread dampening of p53 and NRF2-related genes as early as 4 h after exposure at higher, unrecoverable Zn2+ exposures. Thus, in our model early increased activation of stress response pathways indicated a recoverable adaptive event. Overall, this study highlights the importance of characterizing molecular mechanisms around the tipping point of adverse responses to better inform HTS paradigms.
Developing a Gene Biomarker at the Tipping Point of Adaptive and Adverse Responses in Human Bronchial Epithelial Cells.
Cell line, Time
View SamplesTo investigate the molecular mechanisms associated with initial dose-related events that are linked to the development of liver tumours: liver growth; cell proliferation; changes in histopathology such as hypertrophy
An integrated functional genomic study of acute phenobarbital exposure in the rat.
Specimen part, Time
View SamplesIn an effort to define unique and common signatures of NK cell activity that is non-detected at the protein level, we studied the entire transcriptome of NK cells.
Transcriptomic signatures of NK cells suggest impaired responsiveness in HIV-1 infection and increased activity post-vaccination.
Specimen part, Treatment, Subject
View SamplesThe study aims to define gene expression changes associated with mithramycin treatment of Ewing Sarcoma cell lines.
Identification of an inhibitor of the EWS-FLI1 oncogenic transcription factor by high-throughput screening.
Cell line, Treatment
View SamplesAnalysis of global gene expression profiles of FACS-sorted, human Ad5- and CMV-specific CD4 T cells from the same PBMC sample of healthy donros, using affymetrix Human Gene 2.0ST Gene-Chips;
Preferential infection of human Ad5-specific CD4 T cells by HIV in Ad5 naturally exposed and recombinant Ad5-HIV vaccinated individuals.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Prenatal arsenic exposure and the epigenome: altered microRNAs associated with innate and adaptive immune signaling in newborn cord blood.
Specimen part
View SamplesThe Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Gmez Palacio, Mexico was recently established to better understand the impacts of prenatal exposure to inorganic arsenic (iAs). In this study, we examined a subset (n=40) of newborn cord blood samples for microRNA (miRNA) expression changes associated with in utero arsenic exposure. Levels of iAs in maternal drinking water (DW-iAs) and maternal urine were assessed. Levels of DW-iAs ranged from below detectable values to 236 g/L (mean=51.7 g/L). Total arsenic in maternal urine (U-tAs) was defined as the sum of iAs and its monomethylated and dimethylated metabolites (MMAs and DMAs, respectively) and ranged from 6.2 to 319.7 g/L (mean=64.5 g/L). Genome-wide miRNA expression analysis of cord blood revealed 12 miRNAs with increasing expression associated with U-tAs. Transcriptional targets of the miRNAs were computationally predicted and subsequently assessed using transcriptional profiling. Pathway analysis demonstrated that the U-tAs-associated miRNAs are involved in signaling pathways related to known health outcomes of iAs exposure including cancer and diabetes mellitus. Immune response-related mRNAs were also identified with decreased expression levels associated with U-tAs, and predicted to be mediated in part by the arsenic-responsive miRNAs. Results of this study highlight miRNAs as novel responders to prenatal arsenic exposure that may contribute to associated immune response perturbations.
Prenatal arsenic exposure and the epigenome: altered microRNAs associated with innate and adaptive immune signaling in newborn cord blood.
Specimen part
View SamplesAcute effects caused by the non-genotoxic carcinogen and peroxisome proliferator (PP) diethylhexylphthalate (DEHP) in the mouse liver
Gene ontology mapping as an unbiased method for identifying molecular pathways and processes affected by toxicant exposure: application to acute effects caused by the rodent non-genotoxic carcinogen diethylhexylphthalate.
Sex, Specimen part, Compound, Time
View SamplesThe LH surge triggers dramatic transcriptional changes in genes associated with ovulation and luteinization. The present study investigated the spatiotemporal expression of nuclear factor interleukin-3 (NFIL3), a transcriptional regulator of the bZIP transcription factor superfamily, and its potential role in the ovary during the periovulatory period. NFIL3, also known as E4-binding protein 4 or NFIL3/E4BP4, was originally identified as a transcriptional repressor based on its DNA-binding activity at the promoter of the gene encoding the adenovirus E4 protein. Immature female rats were injected with PMSG, treated with hCG, and ovaries or granulosa cells were collected at various times after hCG. Nfil3 mRNA was highly induced both in intact ovaries and granulosa cells after hCG treatment. In situ hybridization demonstrated that Nfil3 mRNA was highly induced in theca-interstitial cells at 4-8 h after hCG, localized to granulosa cells at 12 h, and decreased at 24 h. Over-expression of NFIL3 in granulosa cells inhibited the induction of prostaglandin-endoperoxide synthase 2 (Ptgs2), progesterone receptor (Pgr), epiregulin (Ereg), and amphiregulin (Areg) and down regulated levels of prostaglandin E2. The inhibitory effect on Ptgs2 induction was reversed by NFIL3 siRNA treatment. In theca-interstitial cells the expression of hydroxyprostaglandin dehydrogenase 15-(NAD) (Hpgd) was also inhibited by NFIL3 over-expression. Data from luciferase assays demonstrated that NFIL3 over-expression decreased the induction of the Ptgs2 and Areg promoter activity. EMSA and ChIP analyses indicated that NFIL3 binds to the promoter region containing the DNA binding sites of CREB and C/EBP?. In summary, hCG induction of NFIL3 expression may modulate the process of ovulation and theca-interstitial and granulosa cell differentiation by regulating expression of PTGS2, PGR, AREG, EREG, and HPGD, potentially through interactions with CREB and C/EBP? on their target gene promoters.
A role for nuclear factor interleukin-3 (NFIL3), a critical transcriptional repressor, in down-regulation of periovulatory gene expression.
Sex
View SamplesLH-indced RUNX2 expression is important for luteal gene expression.
RUNX2 transcription factor regulates gene expression in luteinizing granulosa cells of rat ovaries.
Sex, Age, Specimen part
View Samples