Aging Induced Alterations in Hepatic Gene Expression of the Male Fisher Rat
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE4270 | GEO | 2006/12/17
SECONDARY ACCESSION(S): PRJNA94951
REPOSITORIES: GEO
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Project description:Toxicokinetic and metabolism studies are considered crucial to dose setting and interpretation of data from rodent carcinogenicity studies. The metabolism and distribution studies are usually conducted in 6 to 8 week old rodents. However cancer studies generally involve exposures from 6 weeks of age to 108 weeks or more of age. It is recognized that age-related differences in sensitivities to some xenobiotics occur in several rodent models including the rat. However, the potential for changes in metabolism with age has received little attention in the toxicology community especially in regard to extrapolation of rodent data to human risk assessment. The advent of microarray technology has allowed a more global assessment of genes whose products are associated with xenobiotic metabolism. We studied hepatic gene expression in 38 untreated F344/N rats at approximately 32, 58 and 84 weeks of age corresponding to 6, 12, and 18 months on study. Statistical analysis of microarray (SAM) identified differential expression between the youngest and the oldest rats for genes whose products are involved in phase I and phase II metabolic pathways. Fifteen of 30 cytochrome P450 genes from CYP families 1 â 4 showed marked decrease in expression at 84 weeks while only two showed increased expression. The results of this study demonstrate prominent decreased expression in CYP family genes involved in xenobiotic metabolism in untreated rats as they age. The assumption of a constant metabolic profile when extrapolating results from long-term chemical exposures needs to be reconsidered. Experiment Overall Design: Animals and Study Design. Male Fischer 344 rats approximately 36 ± 3 days old were supplied by Taconic laboratory animals (Germantown, NY) and were approximately six weeks old when placed in study rooms as sentinel animals for two-year studies. All studies were conducted at Battelle Science and Technology International (Columbus, Ohio). The livers from the male rat sentinels from three studies at six months (15 total rats), two studies at twelve months (10 total rats) and three studies at eighteen months (13 total rats) were used in this study. The sampling times corresponded to approximately 32, 58 and 84 weeks of age for the rats. The studies in which the sentinels were a part were approved by Battelleâs Institute Animal Care and Use Committee and were conducted in accordance with the guide for the care and use of laboratory animals (ILAR 1996). Details of the animal care and handling for studies conducted at Battelle have been reported previously (Boorman et al. 2005). Experiment Overall Design: The rats were kept in a cage until necropsy. The rats were anesthetized with CO2/O2, blood samples obtained for serology by cardiac puncture, the abdominal cavity was opened and the portal vein was severed. The left liver lobe was promptly removed and a cross section was placed in 10% neutral buffered formalin (NFB). The liver section was embedded, sectioned and stained with H&E and examined. The remainder of the left lobe was processed for subsequent RNA isolation. Experiment Overall Design: RNA isolation. The left hepatic lobe was cut into 0.5 cm cubes or smaller and immersed in RNALater® (Ambion, Austin, TX) within 4 minutes of necropsy. The tissues were stored in RNALater® overnight at 4+/-30C, then stored at - 20+/-10C until RNA isolation (within 60 days). Details of the RNA isolation procedures have been previous published (Boorman et al. 2005). Briefly, the RNA samples were frozen at - 700 C and shipped to the NTP repository until transfer to Paradigm Array Labs (Icoria, Inc., A Clinical Data Inc. Company, RTP, NC) for microarray analysis. RNA was isolated from individual rats. Equal amounts of RNA from sixty-three male sentinel rats (25 rats at 32 weeks of age, 25 rats at 58 weeks of age and 13 rats at 84 weeks of age) were used to form a composite control pool for comparison with the individual rats at each age. Experiment Overall Design: Microarray Hybridizations. One µg of total RNA from either an individual rat or from the pooled sample was amplified and labeled with a fluorescent dye (either Cy3 or Cy5) using the Low RNA Input Linear Amplification Labeling kit (Agilent Technologies, Palo Alto, CA) following the manufacturerâs protocol. The amount and quality of the resulting fluorescently labeled cRNA was assessed using a Nanodrop ND-100 spectrophometer and an Agilent Bioanalyzer. Equal amounts of Cy3- or Cy5-labeled cRNA were hybridized to the Agilent Rat Oligo Microarray (Agilent Technologies, Inc., Palo Alto, CA) for 17 hrs, prior to washing and scanning. Data was extracted from the resulting images using Agilentâs Feature Extraction Software (Agilent Technologies, Inc., Palo Alto, CA).
2008-06-18 | E-GEOD-4270 | biostudies-arrayexpress
Project description:The microsomes are re-formed vesicle-like artifacts, not ordinarily present in living cells, from pieces of the endoplasmic reticulum (ER), plasma membrane, mitochondria, and Golgi apparatus of broken eukaryotic cells. Typically, microsomes are separated by differential centrifuged from homogenized of cell or tissue. Based on enrichment of ER fractions, prepared microsomes mainly show a large of metabolic activity following high amount of metabolic enzyme, as cytochrome P450 (CYP). CYPs are important components of xenobiotic-metabolizing monooxygenase accounting for an approximate 75% of biotransformation of clinically relevant drugs. Hepatic CYP are ER-anchored hemoproteins involved in the metabolism of numerous endo- and xenobiotics including drugs, steroids, and carcinogens. The CYPs catalytic activity is subject to regulation via phosphorylation. In several previous studies, 8 CYP phosphorylation sites had been discovered in human. Protein kinase A (PKA) and protein kinase C (PKC) were identified as a major catalyst for the phosphorylation of CYPs in 2003. The phosphorylation of CYPs process to their ubiquitination undergoing ubiquitin-dependent 26S proteosomal degradation.
2017-04-04 | PXD003043 | Pride
Project description:The microsomes are re-formed vesicle-like artifacts, not ordinarily present in living cells, from pieces of the endoplasmic reticulum (ER), plasma membrane, mitochondria, and Golgi apparatus of broken eukaryotic cells. Typically, microsomes are separated by differential centrifuged from homogenized of cell or tissue. Based on enrichment of ER fractions, prepared microsomes mainly show a large of metabolic activity following high amount of metabolic enzyme, as cytochrome P450 (CYP). CYPs are important components of xenobiotic-metabolizing monooxygenase accounting for an approximate 75% of biotransformation of clinically relevant drugs. Hepatic CYP are ER-anchored hemoproteins involved in the metabolism of numerous endo- and xenobiotics including drugs, steroids, and carcinogens. The CYPs catalytic activity is subject to regulation via phosphorylation. In several previous studies, 8 CYP phosphorylation sites had been discovered in human. Protein kinase A (PKA) and protein kinase C (PKC) were identified as a major catalyst for the phosphorylation of CYPs in 2003. The phosphorylation of CYPs process to their ubiquitination undergoing ubiquitin-dependent 26S proteosomal degradation.
2015-08-24 | PXD002221 | Pride
Project description:The effect of xenobiotics (phenobarbital and atrazine) on the expression of Drosophila melanogaster CYP genes encoding cytochromes P450, a gene family generally associated with detoxification, was analyzed by DNA microarray hybridization and verified by real time RT-PCR in adults of both sexes. Only a small subset of the 86 CYP genes was significantly induced by the xenobiotics. Eleven CYP genes and three GST genes were significantly induced by phenobarbital, seven CYP and one GST gene were induced by atrazine. Cyp6d5, Cyp6w1, Cyp12d1 and the ecdysone-inducible Cyp6a2 were induced by both chemicals. The constitutive expression of several of the inducible genes (Cyp6a2, Cyp6a8, Cyp6d5, Cyp12d1) was higher in males than in females, and the induced level similar in both sexes. Thus, the level of induction was consistently higher in females than in males. The female-specific and hormonally-regulated yolk protein genes were significantly induced by phenobarbital in males and repressed by atrazine in females. Our results suggest that the numerous CYP genes of Drosophila respond selectively to xenobiotics, providing the fly with an adaptive response to chemically adverse environments. The xenobiotic-inducibility of some CYP genes previously associated with insecticide resistance in laboratory-selected strains (Cyp6a2, Cyp6a8, Cyp12d1) suggests that deregulation of P450 gene expression may be a facile way to achieve resistance. Our study also suggests that xenobiotic-induced changes in P450 levels can affect insect fitness by interfering with hormonally-regulated networks. Keywords: induction by phenobarbital and atrazine in adults drosophila melanogaster of both sex.
2006-06-29 | GSE5125 | GEO
Project description:The soil nematode Caenorhabditis elegans is one of the simplest animals having the status of a laboratory model. Its genome contains 80 cytochrome P450 genes (CYP). In order to study CYP gene expression in C. elegans mixed stages and synchronized hermaphrodites were exposed to 18 known xenobiotic cytochrome P450 inducers. Messenger RNA expression was detected by DNA arrays and semiquantitative RT-PCR. Using subfamily-specific primers, a pooled set of exon-rich CYP fragments could be amplified. In this way it was possible to systematically check the influence of different inducers on CYP expression at the same time. The well-known CYP1A inducers beta-naphthoflavone, PCB52, and lansoprazol were the most active and in particular they strongly induced almost all CYP35 isoforms. A few number of further CYP forms were found to be inducible by other xenobiotics like phenobarbital, atrazine, and clofibrate. In addition, a transgenic C. elegans line expressing GFP under control of the CYP35A2 promoter showed a strong induction of the fusion by beta-naphthoflavone in the intestine. Copyright 2001 Academic Press. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed
2005-11-25 | E-GEOD-3680 | biostudies-arrayexpress
Project description:The Göttingen Minipig is gaining ground as nonrodent species in safety testing of drugs for pediatric indications. Due to developmental changes in pharmacokinetics (PK) and pharmacodynamics (PD), physiologically-based pharmacokinetic (PBPK) models are built to better predict drug exposure in children and to aid species selection for nonclinical safety studies. These PBPK models require high quality physiological and PK/PD data such as protein abundance of drug metabolizing enzymes. These data are available for man and rat, but scarce for the Göttingen Minipig. The aim of this study was to assess hepatic cytochrome P450 (CYP) protein abundance in the developing Göttingen Minipig by using mass spectrometry. In addition, sex-related differences in CYP protein abundance and correlation of CYP enzyme activity with CYP protein abundance were assessed. The following age groups were included: gestational day (GD) 84 - 86 (n = 8), GD 108 (n = 6), postnatal day (PND) 1 (n = 8), PND 3 (n = 8), PND 7 (n = 8), PND 28 (n = 8) and adult (n = 8). Liver microsomes were extracted and protein abundance was compared to that in adult animals. Next, the CYP protein abundance was correlated to CYP enzyme activity in the same biological samples. In general, CYP protein abundance gradually increased during development. However, we observed a stable protein expression over time for CYP4A24 and CYP20A1 and for CYP51A1, a high protein expression during the fetal stages was followed by a decrease during the first month of life and an increase towards adulthood. Sex-related differences were observed for CYP4V2_2a and CYP20A1 at PND 1 with highest expression in females for both isoforms. In the adult samples, sex-related differences were detected for CYP1A1, CYP1A2, CYP2A19, CYP2E1_2, CYP3A22, CYP4V2_2a and CYP4V2_2b with higher values in female compared to male Göttingen Minipigs. The correlation analysis between CYP protein abundance and CYP enzyme activity showed that CYP3A22 protein abundance correlated clearly with the metabolism of midazolam at PND 7. These data are remarkably comparable to human data and provide a valuable step forward in the construction of a neonatal and juvenile Göttingen Minipig PBPK model.
2021-02-26 | PXD024158 | Pride
Project description:The soil nematode Caenorhabditis elegans is one of the simplest animals having the status of a laboratory model. Its genome contains 80 cytochrome P450 genes (CYP). In order to study CYP gene expression in C. elegans mixed stages and synchronized hermaphrodites were exposed to 18 known xenobiotic cytochrome P450 inducers. Messenger RNA expression was detected by DNA arrays and semiquantitative RT-PCR. Using subfamily-specific primers, a pooled set of exon-rich CYP fragments could be amplified. In this way it was possible to systematically check the influence of different inducers on CYP expression at the same time. The well-known CYP1A inducers beta-naphthoflavone, PCB52, and lansoprazol were the most active and in particular they strongly induced almost all CYP35 isoforms. A few number of further CYP forms were found to be inducible by other xenobiotics like phenobarbital, atrazine, and clofibrate. In addition, a transgenic C. elegans line expressing GFP under control of the CYP35A2 promoter showed a strong induction of the fusion by beta-naphthoflavone in the intestine. Copyright 2001 Academic Press. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-11-26 | GSE3680 | GEO
Project description:Dahl salt-sensitive (DS) rats were obtained from Harlan Sprague Dawley Laboratory at 5 weeks of age. At 6 weeks of age, physiologic cardiac hypertrophy was generated by a vigorous daily exercise regimen for 6 weeks (e group). The exercise protocol is based on those described previously with modifications (Wisloff U et al., 2001; Jin H et al., 1994). Rats were exercised daily for 6 weeks on a rodent treadmill (Exer-6M; Columbus Instruments). The exercise program consisted of three weeks of progressively strenuous exercise regimens; followed by three weeks of maintenance period, during which the rats were exercised at 16 m/min at a 5o incline for 90 minutes/day. All rats completed the exercise protocol. Pathological cardiac hypertrophy was generated by feeding a 6% NaCl diet to DS rats at 6 weeks of age (h group) (Inoko M et al., 1994). Control rats (c group) were age matched and sedentary DS rats fed normal rat chow. Read more at http://cardiogenomics.med.harvard.edu/groups/proj1/pages/rat_home.html Keywords: other
2003-10-24 | GSE776 | GEO
Project description:Analysis of liver with or without Cytochrome P450 (Cyp) 3a-cluster. Cyp3a family is one of the most important enzymes for drug metabolism. These results suggest the biological effects of Cyp3a-knockout on liver.
2018-11-15 | GSE103533 | GEO
Project description:Many of the enzymes involved in xenobiotic metabolism are maintained at a low basal level and are only synthesized in response to activation of upstream sensor/effector proteins. This induction can have implications in a variety of contexts, particularly during the study of the pharmacokinetics, pharmacodynamics and drug-drug interaction profile of a candidate therapeutic compound. Previously, we combined in vivo SILAC material with a targeted high resolution single ion monitoring (tHR/SIM) LC-MS/MS approach for quantification of 197 peptide pairs, representing 51 drug metabolism enzymes (DME), in mouse liver. However, as important enzymes (for example, cytochromes P450 (Cyp) of the 1a and 2b subfamilies) are maintained at low or undetectable levels in the liver of unstimulated metabolically-labelled mice, quantification of these proteins was unreliable. In the present study, we induced DME expression in labelled mice through synchronous ligand-mediated activation of multiple upstream nuclear receptors, thereby enhancing signals for proteins including Cyps 1a, 2a, 2b, 2c and 3a. With this enhancement, 115 unique, lysine-containing, Cyp-derived peptides were detected in the liver of a single animal, as opposed to 56 in a pooled sample from three uninduced animals. A total of 386 peptide pairs were quantified by tHR/SIM, representing 68 Phase I, 30 Phase II and 8 control proteins. This method was employed to quantify changes in DME expression in the hepatic cytochrome P450 reductase null (HRN) mouse. We observed compensatory induction of several enzymes, including Cyps 2b10, 2c29, 2c37, 2c54, 2c55, 2e1, 3a11 and 3a13, carboxylesterase (Ces) 2a and glutathione S-transferases (Gst) m2 and m3, along with down-regulation of hydroxysteroid dehydrogenases (Hsd) 11b1 and 17b6. Using DME-enhanced in vivo SILAC material with tHR/SIM, therefore, permits the robust analysis of multiple DME of import to xenobiotic metabolism, with improved utility for the study of drug pharmacokinetics, pharmacodynamics, and of chemically-treated and genetically-modified mouse models.
2015-01-09 | PXD001210 | Pride