Transcription profiling of mouse liver and cecum after exposure to aflatoxin B1 (AFB1) and/or Helicobacter hepaticus
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ABSTRACT: We evaluated aflatoxin B1-induced liver tumor promotion by H. hepaticus. Microarrays of liver and cecum from female mice were used to evaluate the individual and combined transcriptional effects of AFB1 and H. hepaticus Experiment Overall Design: C3H/HeN mice were inoculated with 7 ug/g BW AFB1 or vehicle IP at 10 days of age, and gavaged with H. hepaticus or broth at 3 weeks; necropsied at 40 weeks
Project description:We evaluated aflatoxin B1-induced liver tumor promotion by H. hepaticus. Microarrays of liver and cecum from female mice were used to evaluate the individual and combined transcriptional effects of AFB1 and H. hepaticus Keywords: Tumor co-promotion study
Project description:We are investigating hepatic transcriptional responses associated with castration and tumorigenic hepatitis induced by Helicobacter hepaticus infection in mature male A/JCr mice; Microarray data demonstrated a global loss of gender-dimorphic gene expression regulation in mice with chronic hepatitis and liver cancer Experiment Overall Design: Male A/JCr mice were inoculated with H. hepaticus or vehicle at 4 weeks; some underwent castration at 1 year, and all were necropsied at 21 months
Project description:Viral hepatitis and aflatoxin B1 (AFB1) exposure are common risk factors for hepatocellular carcinoma (HCC). The incidence of HCC in individuals co-exposed to hepatitis C (HCV) or B virus and AFB1 is greater than could be explained by the additive effect, yet the mechanisms are poorly understood due to lack of an animal model. This study investigated the outcomes and mechanisms of combined exposure to HCV and AFB1. We hypothesized that HCV transgenic (HCV-Tg; expressing core, E1, E2, and p7, nucleotides 342-2771) mice will be prone to hepatocarcinogenesis when exposed to AFB1. Neonatal (7 days old) HCV-Tg or C57BL/6J wild-type mice were exposed to AFB1 (6 ug/g bw) or tricaprylin vehicle (15 ul/g bw) and male offspring were followed for up to 12 months. No liver lesions were observed in vehicle-treated wild type or HCV-Tg mice. Tumors (adenomas or carcinomas) and preneoplastic lesions (hyperplasia or foci) were observed in 22.5% (9 of 40) of AFB1-treated wild-type mice. In HCV-Tg, the incidence of tumorous or pre-tumorous lesions was significantly elevated (50%, 18 of 36), with the difference largely due to a 2.5-fold increase in the incidence of adenomas (30.5% vs 12.5%). While oxidative stress and steato-hepatisis were observed in both AFB1-treated groups, molecular changes indicative of the enhanced inflammatory response and altered lipid metabolism were more pronounced in HCV-Tg mice. In summary, HCV proteins core, E1, E2 and p7 are sufficient to reproduce the additive co-carcinogenic effect of HCV and AFB1 which is a known clinical phenomenon. HCV transgenic mice (SL-139 strain, pAlbSVPA-HCV-S, containing the structural genes core, E1, E2, and p7, nucleotides 342-2771 of HCV genotype 1b, strain N, under the control of the murine albumin promoter/enhancer) on C57BL/6J (Jackson Laboratory, Bar Harbor, ME) background were previously reported in Lerat et al (Lerat et al., Gastroenterology 122, 352-365, 2002). Transgenic animals were identified after weaning as detailed in Korenaga et al (Korenaga et al., J Biol. Chem. 280, 37481-37488, 2005). Neonatal (7 days old) mice were administered a single dose of AFB1 (6 ug/g bw) or tricaprylin vehicle (15 ul/g bw) by intra-peritoneal injection. Male mice were maintained on the regular animal chow with free access to food and water for up to 12 months. All animal experiments were approved by the UNC Animal Care and Use Committee. There were 20 liver samples used for microarray analysis (12 month time point). All samples were run in one batch. There are 4 groups: WT/Control (4 samples - all biological replicates, i.e., different animals); WT/AFB1 (6 samples); HCV/Control (4 samples); HCV/AFB1 (6 samples). This was a 2 color design with a common reference mRNA. No dye swaps or replicate arrays were included.
Project description:We are investigating the transcriptional response of mice infected with Helicobacter hepaticus and links to liver cancer; We used microarrays to detail the global programme of gene expression underlying H. hepaticus induced liver cancer Experiment Overall Design: Mice with tumors were compared to mice with infection only (comparison 2) and mice infected were compared to control mice (comparison 1)
Project description:Applied de novo assembly, both protein coding and non-coding RNAs were profiled in AFB1 induced HCC and AFB1 resistant liver sample. Compared with normal liver, the perturbation on transcriptome was revealed in multiple aspects, implying the potential mechanism of toxic resistance.
Project description:Applied de novo assembly, both protein coding and non-coding RNAs were profiled in AFB1 induced HCC and AFB1 resistant liver sample. Compared with normal liver, the perturbation on transcriptome was revealed in multiple aspects, implying the potential mechanism of toxic resistance. All rats were randomly divided into control and treated groups according to their weight. Then AFB1 was injected intraperitoneally to treated group in customized schedule. Biopsy was applied every 10 weeks on both groups. Tissues from rats died of HCC were reserved. All rats were sacrificed at 70th week. According to whether tumor formed, liver tissues from animals in treated group were further divided into AFB1 induced tumor sample and AFB1 resistant sample. Both samples were stored for later transcriptome analysis, as well as the normal sample from control group. RNA profiles of all 3 samples were generated by deep sequencing, using Illumina HiSeq2000 platform.
Project description:We report that liver nodules from 5/8 (62.5%) male and 4/5 (80%) female Gnmt-/- mice were diagnosed as having HCC. Microarray analysis showed that genes involved in the following pathways were deregulated in different stages of tumorigenesis: Methylation, metabolism, signal transduction, cell proliferation, and cell adhesion. This study reveals that GNMT plays an important role in the prevention of hepatotumorigenesis through regulating detoxification pathways. We postulate that GNMT is a stress-responsive protein and its expression may account for the gender difference of the susceptibility to liver cancer. Liver tissues from aflatoxin B1 (AFB1)-treated wild-type or Gnmt knockout mice at 11weeks old were used for RNA extraction and hybridization on Affymetrix microarrays. Total RNA were mixed in equal proportion from 3 mice.
Project description:We are investigating the transcriptional response of mice infected with Helicobacter hepaticus and links to liver cancer We used microarrays to detail the global programme of gene expression underlying H. hepaticus induced liver cancer Keywords: disease model
Project description:Comparison of gene expression profiles induced by the mycotoxin, aflatoxin B1 (AFB1), in primary human hepatocytes and HepaRG cells. Initial mechanisms involved in the complex multistep process leading to malignant transformation by chemicals remain largely unknown. We have analysed changes in gene expression profiles in primary human hepatocytes and differentiated human hepatoma HepaRG cells after a 24 h treatment with 0.05 or 0.25µM aflatoxin B1 (AFB1), a potent genotoxic hepatocarcinogen. Three independent biological replicates of HepaRG cell cultures and two pools of three primary human hepatocyte cultures each, were investigated. Cells were treated with 0.05 or 0.25µM AFB1 for 24 h.