Effect of paternal inorganic arsenic exposure on transcriptional profilings of F1-male liver in mouse
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ABSTRACT: Adult male mice (F0) were exposed to 250 ppb inorganic arsenic (iAs) in drinking water before mating with unexposed female mice to generate male F1 offspring (iAsF1-M). Unexposed male mice were bred simultaneously to generate male controls (conF1-M). Both iAsF1-M and conF1-M mice drank normal water without iAs. Adult iAsF1-M and conF1-M mice were harvested to collect liver samples to do RNA-seq.
Project description:Background: Chronic exposure to inorganic arsenic (iAs) has been associated with type 2 diabetes (T2D). However, potential sex divergence and the underlying mechanisms remain understudied. iAs is not metabolized uniformly across species, which is a limitation of typical exposure studies in rodent models. The development of a new “humanized” mouse model overcomes this limitation. In this study, we leverage this model to study sex differences in the context of iAs exposure. Objectives: The aim of this study iwas to determine if males and females exhibit different liver and adipose molecular profiles and metabolic phenotypes in the context of iAs exposure. Methods: Our study was performed on wild-type (WT) 129S6/SvEvTac and humanized arsenic +3 methyl transferase (human AS3MT) 129S6/SvEvTac mice treated with 400 ppb of iAs via drinking water ad libitum. After 1 month, mice were sacrificed and the liver and epididymales gonadal adipose depot were harvested for iAs quantification as well as sequencing-based microRNA and gene expression analysis. Serum blood was collected for fasting blood glucose, fasting plasma insulin, and HOMA-IR. Results: We detected sex divergence in liver and adipose markers of diabetes (e.g., insulin signaling pathways, fasting blood glucose, fasting plasma insulin, and HOMA-IR) only in humanized (not WT) male mice. In humanized female mice, numerous genes that promote insulin sensitivity and glucose tolerance in both the liver and adipose are elevated compared to humanized male mice. We also identified Klf11 as a putative master regulator of the sex divergence in gene expression in humanized mice. Discussion: Our study underscoreds the importance of future studies leveraging the humanized mouse model to study iAs-associated metabolic disease. The findings also suggest suggested that humanized females are protected from metabolic dysfunction relative to humanized males in the context of iAs exposure. Future investigations should focus on the detailed mechanisms that underlie the sex divergence, including the potential role of miR-34a and/or Klf11.
Project description:Inorganic arsenic (iAs) is a widespread environmental toxin. In addition to being a human carcinogen, its effect on systemic glucose metabolism has started to gain recognition recently. However, its in vivo effect on insulin sensitivity is not clear. Here we use mouse models to dissect the dose-dependent effects of iAs in glucose metabolism. We found that a low-dose exposure (0.25 ppm iAs in drinking water) caused glucose intolerance in adult male C57BL/6 mice, likely by disrupting glucose-induced insulin secretion without affecting peripheral insulin sensitivity. However, a higher-dose exposure (2.5 ppm iAs) has diminished effects on glucose tolerance despite disrupted pancreatic insulin secretion. We performed hyperinsulinemic euglycemic clamp, the gold standard analysis of systemic insulin sensitivity, and found that the 2.5 ppm iAs enhanced systemic insulin sensitivity by simultaneously enhancing insulin-stimulated glucose uptake in skeletal muscles and insulin-mediated suppression of endogenous glucose production. RNA-seq analysis of muscles revealed that 2.5 ppm iAs regulated expression of many genes involved in the metabolism of fatty acids, pyruvate, and amino acids. These findings suggest that iAs has distinct effects on distinct metabolic tissues at different dose thresholds, which could help reconcile some of the conflicting epidemiological results. The study shed light on the complex interactions between an environmental factor and the systemic glucose metabolism.
Project description:We treated C56BL/6 male mice with 0.25 ppm iAs in drinking water before breeding with untreated females. GTT and other metabolic assaies were done on F1 offsprings. iAsF1-F showed significantly impared glucose intolerance than conF1-F. RNA-seq was thus applied to the liver samples of F1 generation to explore potential mechanism.
Project description:HTR-8/SVneo human placental trophoblast cells were exposed to low-level environmentally relevant concentrations of iAs, Mn, and iAs-Mn mixtures. A microarray assay was performed to understand the changes and differences in gene expression in relation to single-metal and metal-mixtures
Project description:Chronic exposure to inorganic arsenic (iAs) or a high-fat diet (HFD) can produce liver injury. However, the interactive molecular biological effects and mechanism of iAs and HFD are as of yet unclear. We used microarrays to detail the interactive effects of arsenic and a high-fat diet on hepatic gene expression. The C57BL/6 Mice fed low-fat diet (LFD) or HFD were exposed to 3 mg/L iAs or deionized water for 10 weeks. Then, hepatic RNA were extraction and hybridization on Affymetrix microarrays. Differentially expressed genes in LFD+As, HFD, and HFD+As groups compared to LFD group were identified, and interactive molecular biological effects and mechanism of iAs and HFD were discussed.
Project description:Purpose: To determine the effects of sodium arsenite in male mice on adaptive thermogenesis. Methods: Male C57BL/6J mice were exposed to sodium arsenite in drinking water at 300 parts per billion (ppb) for 9 weeks Findings: Arsenic-treated mice experienced significantly decreased metabolic heat production when acclimated to chronic cold tolerance testing, as evidenced by indirect calorimetry, despite no change in physical activity. Arsenic exposure increased total fat mass, and unilocular lipid droplet size in both subcutaneous inguinal white adipose tissue (iWAT) and brown adipose tissue (BAT). Conclusion: Chronic arsenic exposure impacts the mitochondria of thermogenic tissues involved in energy expenditure and glucose regulation, providing novel mechanistic evidence for arsenic’s role in metabolic pathologies.
Project description:To examine the global impact of iAs on DNA methylation patterns. Genomic DNA was bisulfite converted and analyzed using Infinium MethylationEPIC BeadChip.
Project description:According to the developmental origins of health and disease (DOHaD) hypothesis, exposure to environmental stressors during early development can cause genetic, epigenetic, or functional changes in tissues that increase disease risk later in life. Atrazine (ATZ) is a commonly used pesticide that frequently contaminates rural and urban water sources at levels above the 3 ppb maximum contaminant level set by the US Environmental Protection Agency. Exposure to ATZ is linked to endocrine disruption, cancer, changes in genome methylation, and alterations in neurochemistry and behavior. This study tests the hypothesis that embryonic exposure to ATZ results in sex-specific changes in behavior, the adult brain transcriptome, and adult body and brain pathology, according to the DOHaD hypothesis. Zebrafish (Danio rerio) embryos were exposed to 0, 0.3, 3, or 30 ppb (ppb; µg/L) ATZ during the period from fertilization through 72 hours post fertilization (hpf), and then were rinsed and raised to maturity with no further exposure. At 9 months post fertilization (mpf), a novel tank test, a light-dark box, and an open field test evaluated adult behavior. Transcriptomic analysis investigated ATZ related differences in gene expression and the brain was evaluated histopathologically for morphometric alterations in the area of the dorsal telencephalon, posterior tuberculum, and raphe populations. At 14 mpf, the body length, weight, and brain weight was measured to evaluate effects of ATZ on mature body and brain size. The 9 mpf adult behavioral tests found non-monotonic, sex-specific behavior changes, with male zebrafish having decreased activity and female zebrafish having increased signs of anxiety. Transcriptomic analysis identified sex-specific alterations, with females having altered expression of genes in pathways related to cancer and organismal injury and males having altered gene expression in organismal development and reproductive system development and function pathways. Morphometric analysis identified a decreased number of cells in male raphe populations and adult zebrafish also had non-monotonic, sex-specific alterations in body length, body weight, and brain weight. This results suggests that developmental exposure to ATZ does cause sex-specific alterations in adult neural function.
Project description:According to the developmental origins of health and disease (DOHaD) hypothesis, exposure to environmental stressors during early development can cause genetic, epigenetic, or functional changes in tissues that increase disease risk later in life. Atrazine (ATZ) is a commonly used pesticide that frequently contaminates rural and urban water sources at levels above the 3 ppb maximum contaminant level set by the US Environmental Protection Agency. Exposure to ATZ is linked to endocrine disruption, cancer, changes in genome methylation, and alterations in neurochemistry and behavior. This study tests the hypothesis that embryonic exposure to ATZ results in sex-specific changes in behavior, the adult brain transcriptome, and adult body and brain pathology, according to the DOHaD hypothesis. Zebrafish (Danio rerio) embryos were exposed to 0, 0.3, 3, or 30 ppb (ppb; µg/L) ATZ during the period from fertilization through 72 hours post fertilization (hpf), and then were rinsed and raised to maturity with no further exposure. At 9 months post fertilization (mpf), a novel tank test, a light-dark box, and an open field test evaluated adult behavior. Transcriptomic analysis investigated ATZ related differences in gene expression and the brain was evaluated histopathologically for morphometric alterations in the area of the dorsal telencephalon, posterior tuberculum, and raphe populations. At 14 mpf, the body length, weight, and brain weight was measured to evaluate effects of ATZ on mature body and brain size. The 9 mpf adult behavioral tests found non-monotonic, sex-specific behavior changes, with male zebrafish having decreased activity and female zebrafish having increased signs of anxiety. Transcriptomic analysis identified sex-specific alterations, with females having altered expression of genes in pathways related to cancer and organismal injury and males having altered gene expression in organismal development and reproductive system development and function pathways. Morphometric analysis identified a decreased number of cells in male raphe populations and adult zebrafish also had non-monotonic, sex-specific alterations in body length, body weight, and brain weight. This results suggests that developmental exposure to ATZ does cause sex-specific alterations in adult neural function.
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 using 0 and 100 ppb-TCDD treated male and female sexed zebrafish at 7, 14, 28 and 42 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. At 42d, no mature female fish were observed.