Project description:Acrylamide, a high-production-volume chemical and food contaminant in baked and fried carbohydrate-rich foods has been classified as a “Group 2A carcinogen” (probable human carcinogen) by the IARC. The carcinogenicity of acrylamide is attributed to its well-recognized genotoxicity; however, evidence suggests that acrylamide may also induce non-genotoxic alterations. In the present study female B6C3F1 mice were exposed to 0.70mM acrylamide in drinking water for 28 days and genotoxic and transcriptomic effects were investigated in the lung, a target organ for acrylamide carcinogenicity in mice, and the liver, a non-target organ. Acrylamide exposure resulted in a dose-dependent formation of N7-(2-carbamoyl-2-hydroxyethyl)guanine and N3-(2-carbamoyl-2-hydroxyethyl)adenine in lung and liver DNA at the similar levels. In contrast, whole genome gene expression profiles in the lungs and livers revealed the tissue-specific gene expression alterations. By using a SurePrint G3 Mouse Gene Expression v2 8x60K Microarray Kit (Agilent Technologies), we identified 123 and 363 genes that were found to be differentially expressed in the lungs and livers of acrylamide-treated mice; however, only 5 genes were in common between the organs. A detailed analysis of differentially expressed genes revealed that the major difference in the effect of acrylamide on the transcriptome in the lungs and livers was related to a different trend of gene expression changes. In the lungs, acrylamide exposure caused an inhibition of gene expression (54 up-regulated and 69 down-regulated genes), whereas the opposite effect, characterized by twice the number of up-regulated as compare to down-regulated genes (245 up-regulated and 118 down-regulated), was found in the livers of exposed mice.
Project description:Acrylamide is a reproductive toxicant that has been detected in foods such as potato chips and breads. The consequences of chronic exposure to acrylamide in the human diet are unknown; however we previously reported that exposure to acrylamide at levels equivalent to human exposure produced high levels of genetic damage in early male germ cells of mice [Nixon et al. ToxSci 129(1), 135–145 (2012)]. In the present study, we examined changes in testicular gene expression in these mice to examine the potential mechanisms involved in acrylamide induced DNA damage in male germ cells and to provide a better understanding of the reproductive toxic effects of acrylamide in the male.
Project description:Acrylamide is a reproductive toxicant that has been detected in foods such as potato chips and breads. The consequences of chronic exposure to acrylamide in the human diet are unknown; however we previously reported that exposure to acrylamide at levels equivalent to human exposure produced high levels of genetic damage in early male germ cells of mice [Nixon et al. ToxSci 129(1), 135–145 (2012)]. In the present study, we examined changes in testicular gene expression in these mice to examine the potential mechanisms involved in acrylamide induced DNA damage in male germ cells and to provide a better understanding of the reproductive toxic effects of acrylamide in the male. Adult male mice were subjected to chronic acrylamide exposure via the drinking water at concentrations of 0, 0.001, 0.01, 0.1, 1 and 10 µg/ml for 1, 6 and 12 months. The testes were collected at each time point for RNA extraction and hybridization on an Illumina Sentrix Mouse ref-8 v2 Beadchip.
Project description:Acrylamide is a type-2 alkene monomer with established human neurotoxic effects. While the primary source of human exposure to acrylamide is occupational, other exposure sources include food, drinking water, and smoking. In this study, neurobehavioral assays coupled with transcriptional profiling analysis were conducted to assess both behavioral and gene expression effects induced by acrylamide neurotoxicity in rats when administered during early postnatal life. Acrylamide administration in rat pups induced significant characteristic neurotoxic symptoms including increased heel splay, decrease in grip strength, and decrease in locomotor activity. Transcriptome analysis with the Affymetrix Rat Genome 230 2.0 array indicated that acrylamide treatment caused a significant alteration in the expression of genes involved in muscle contraction, pain regulation, and dopaminergic neuronal pathways. First, in agreement with the observed behavioral effects, expression of the Mylpf gene involved in muscle contraction was downregulated in the spinal cord in response to acrylamide. Second, in sciatic nerves, acrylamide repressed the expression of the opioid receptor gene Oprk1 that is known to play a role in neuropathic pain regulation. Finally, in the cerebellum, acrylamide treatment caused a decrease in the expression of the nuclear receptor gene Nr4a2 that is required for development of dopaminergic neurons. Thus, our work examining the effect of acrylamide at the whole-genome level on a developmental mammalian model has identified novel genes previously not implicated in acrylamide neurotoxicity that can be further developed into biomarkers for assessing the risk of acrylamide exposure.
Project description:Acrylamide is a type-2 alkene monomer with established human neurotoxic effects. While the primary source of human exposure to acrylamide is occupational, other exposure sources include food, drinking water, and smoking. In this study, neurobehavioral assays coupled with transcriptional profiling analysis were conducted to assess both behavioral and gene expression effects induced by acrylamide neurotoxicity in rats when administered during early postnatal life. Acrylamide administration in rat pups induced significant characteristic neurotoxic symptoms including increased heel splay, decrease in grip strength, and decrease in locomotor activity. Transcriptome analysis with the Affymetrix Rat Genome 230 2.0 array indicated that acrylamide treatment caused a significant alteration in the expression of genes involved in muscle contraction, pain regulation, and dopaminergic neuronal pathways. First, in agreement with the observed behavioral effects, expression of the Mylpf gene involved in muscle contraction was downregulated in the spinal cord in response to acrylamide. Second, in sciatic nerves, acrylamide repressed the expression of the opioid receptor gene Oprk1 that is known to play a role in neuropathic pain regulation. Finally, in the cerebellum, acrylamide treatment caused a decrease in the expression of the nuclear receptor gene Nr4a2 that is required for development of dopaminergic neurons. Thus, our work examining the effect of acrylamide at the whole-genome level on a developmental mammalian model has identified novel genes previously not implicated in acrylamide neurotoxicity that can be further developed into biomarkers for assessing the risk of acrylamide exposure. Three-week-old male Wistar rat pups were treated with either acrylamide or saline daily (30 mg/kg) for 21 days, then tissues (cerebellum, spinal cord, and sciatic nerve) were harvested and frozen. Two biological replicate samples, each sample consisting of pooled tissue from 2 rats, were analyzed for each treatment.
Project description:To invistigate the role of IL-1B in acrylamide toxicity in mice, we establish the IL-1B knockdown mice to invistagate if it have a protective effect against acrylamide neurotoxicity
Project description:The seminal vesicles synthesise bioactive factors that support gamete function, modulate the female reproductive tract to promote implantation, and influence developmental programming of offspring phenotype. Despite the significance of the seminal vesicles in reproduction, their biology remains poorly defined. Here, to advance understanding of seminal vesicle biology, we analyse the mouse seminal vesicle transcriptome under normal physiological conditions and in response to acute exposure to the reproductive toxicant acrylamide. Mice were administered acrylamide (25 mg/kg bw/day) or vehicle control daily for five consecutive days prior to collecting seminal vesicle tissue 72 h following the final injection.
Project description:Paternal exposure to environmental stressors elicits distinct changes to the sperm sncRNA profile; modifications that have significant post-fertilization consequences. Despite this knowledge, there remains limited mechanistic understanding of how paternal exposures modify the sperm sncRNA landscape. Here, we report the acute sensitivity of the sperm sncRNA profile to the reproductive toxicant, acrylamide. Further, we traced the differential accumulation of acrylamide-responsive sncRNAs to coincide with sperm transit of the proximal (caput) segment of the epididymis, wherein acrylamide exposure altered the abundance of several transcription factors implicated in the expression of acrylamide-sensitive sncRNAs. We also identified extracellular vesicles secreted from the caput epithelium in relaying altered sncRNA profiles to maturing spermatozoa, and dysregulated gene expression during early embryonic development following fertilisation by acrylamide-exposed spermatozoa. These data provide mechanistic links to account for how environmental insults can alter the sperm epigenome and compromise the transcriptomic profile of early embryos.
Project description:In a genome-wide RNAi screen to identify activators of numr-1, a cadmium responsive gene involved in RNA splicing regulation, we isolated ccf-1 as a gene that is required for cadmium-induced numr-1 activation. The ccf-1 gene encodes a deadenylase within the CCR4-NOT complex that generally serves to suppress gene expression by initiating mRNA degradation. However, a role for ccf-1 as a positive regulator of stress-induced gene expression remains to be characterized. Silencing of ccf-1 inhibits various classes of cadmium-inducible genes including several glutathione-s-transferase (gst) and heat shock protein genes. RNAi knockdown of ccf-1 significantly reduces lifespan and decreases survival in cadmium, implicating a role for ccf-1 in aging and stress protection. The ccf-1 gene is also required for resistance against acrylamide with RNAi depletion of ccf-1 inhibiting acrylamide-induced gst induction, decreasing survival in acrylamide stress, and increasing C. elegans sensitivity to acrylamide-induced neurodegeneration. Using RNA-sequencing, we observed that ccf-1 regulates ~28-35% of all genes induced by cadmium (500 out of 1802 DEG) or acrylamide (296 out of 851 DEG) by >2-fold. Clustering analysis of ccf-1 dependent cadmium or acrylamide up-regulated genes indicate significant enrichment to glutathione and cytochrome P450 metabolism, suggesting a central role for ccf-1 in regulating antioxidant defense across different stressors. Using a CCF-1::GFP translational reporter, we find that CCF-1 is broadly expressed in the intestine, muscle, and hypodemis. Interestingly, CCF-1::GFP strongly localizes to the intestinal nuclei, implicating a potential nuclear role for CCF-1 in transcriptional regulation that is distinct for its deadenylase function in the cytoplasm
Project description:Here we investigated the longterm carryover effects of dichloroacetic acid (DCA), a common by-product of drinking water chlorination, on hepatic tumorigenesis in mice. Our findings demonstrate that postnatal exposure to a common drinking water contaminant results in longterm carryover effects on tumorigenesis, potentially via epigenetic events altering cellular respiration and metabolism.