Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling of rat livers after treatment with control, BNF, D3T, and OLT

ABSTRACT: Test compound one, 5,6-benzoflavone (BNF), was known to act through both the Ah receptor and Nrf2 receptor pathways, while test compounds two and three, 3H-1,2-dithiole-3-thione (D3T) and 4-methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (OLT), were known to act through the Nrf2 receptor pathway. Furthermore, D3T is known to be more potent and efficacious than OLT for Nrf2 activation. OLT has been shown to exhibit 20-50% of the efficacy of D3T for inhibition of alfatoxin-induced heptic foci. Nonetheless, because OLT is an approved drug, it is currently being evaluated in human phase II intervention trials of biomarkers of alfatoxin-related hepatocellular carcinoma. More recently, BNF was shown to be an effective chemopreventive agent in the rat mammary carcinogen model, inhibiting 7,12-dimethylbenz(a)anthracene DNA adduct formation in liver and mammary cells by 96 and 83% respectively. We used microarrays to study the structure activities that lie within the test compounds. Experiment Overall Design: Twenty female Sprague Dawley rats, were randomly divided into 4 groups of 5 each. Each group of rats were fed with Harlan Teklad Rodent diet, 4% mash diet (Control) or the same formulation containing either, 5,6-benzoflavone (BNF, 1650 mg/kg diet), 3H-1,2-dithiole-3-thione (D3T, 600 mg/kg diet), or 4-methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (OLT, 500 mg/kg diet), for 24 days. The rats were sacrificed with carbon dioxide. The livers were harvested within 3 min, rapidly frozen in liquid nitrogen, and stored at -80oC until they were processed

ORGANISM(S): Rattus norvegicus

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PROVIDER: E-GEOD-8880 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:The activities of the dithiolethione analogs, D3T, OLT, and TBD are pharmacologically well-understood. These compounds act as chemopreventive agents whose ability is to block or diminish early stages of carcinogenesis. In addition, the three compounds are classified as monofunctional Phase II enzyme inducers and activate the same pathway, namely the Keap1-Nrf2 signal pathway. The three dithiolethiones were showed to ameliorate the AFB1-induced toxicity through increasing phase II enzymes including glutathione S-transferase (GST). The parent D3T was observed to be the most potent chemoprotective agent. Oltipraz, a clinically approved drug, has been shown to exhibit less efficacy than its analogs for inhibition of aflatoxin-induced hepatic foci.TBD was suggested to be better than OLT as a chemopreventive agent because of its reduced toxicity profile. Thus based on gene expressions, our goal is to study the closely related structure activities that lie within the three compounds and the activity of OLT versus TBD at the 5 position of their dithiole rings and to determine whether the activity of TBD is closely related to OLT or its parent D3T. Experiment Overall Design: Male Fischer F344 rats (80-100g) were obtained from Harlan at 6 wk of age. General procedures for animal care and housing were in accordance with the Guide for the Care and use of Laboratory Animals, National Research Council, 1996. The animals were singly housed in polycarbonate cages in a temperature (22 ± 1°C)- and humidity (30-70%)-controlled room with a 14:10-h light-dark cycle, respectively. Rat AIN 76A chow (Harlan Teklad) and tap water were provided at libitum. Sixteen animals were randomly assigned into four groups (n=16) and treated by gavage with 100?l of either vehicle (saturated sucrose), 3H-1,2-dithiole-3-thione (D3T), (0.3 mmol/kg body wt), 4-methyl-5-pyrazinyl-3H-1,2-dithiole-3-thione (oltipraz-OLT), (0.3 mmol/kg), and 5-tert-butyl-3H-1,2-dithiole-3-thione (TBD) , (0.3mmol/kg body wt), once every other day for 5 days. Animals were killed 24h after the third dose. Liver tissues were harvested and snap frozen. The protocol for this study was approved by the University of Memphis Animal Care Committee and Johns Hopkins University.

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Project description:Evidence from multiple linkage and genome-wide association studies suggest that human chromosome 2 (HSA2) contains alleles that influence blood pressure (BP). Homologous to a large segment of HSA2 is rat chromosome 9 (RNO9), to which a BP quantitative trait locus (QTL) was previously mapped. The objective of the current study was to further resolve this BP QTL. Eleven congenic strains with introgressed segments spanning <81.8kb to <1.33Mb were developed by introgressing genomic segments of RNO9 from the Dahl salt-resistant (R) rat onto the genome of the Dahl salt-sensitive (S) rat and tested for BP. The congenic strain with the shortest introgressed segment spanning <81.8kb significantly lowered BP of the hypertensive S rat by 25 mm Hg and significantly increased its mean survival by 45 days. In contrast, two other congenic strains had increased BP compared with the S. We focused on the <81.8kb congenic strain which represents the shortest genomic segment to which a BP QTL has been definitively mapped to date in any species. Sequencing of this entire region in both S and R rats detected 563 variants. The region did not contain any known or predicted rat protein coding genes. Further, a whole genome renal transcriptome analysis between S and the <81.8kb S.R congenic strain revealed alterations in several critical genes implicated in renal homeostasis. Taken together, our results provide the basis for future studies to examine the relationship between the candidate variants within the QTL region and the renal differentially expressed genes as potential causal mechanisms for BP regulation. Six male S control and 6 male congenic S.R(9)x3x2Bx1x8 rats born on the same day were selected, weaned at 30 days of age, and caged with 1 congenic and 1 S rat per cage. They were raised on a High-salt (2%) diet (Harlan Teklad diet TD 7034; Harlan–Sprague-Dawley) and sacrificed at 53 days of age and total RNAs were isolated from the kidney. The isolated RNA from two animals were pooled together and considered as one biological sample. Three such RNA samples from S and congenic rats were used for the cRNA preparation. cRNA was prepared and fragmented as suggested by Affymetrix technical manual, and simultaneously hybridized (15 µg adjusted cRNA for each chip) to Rat Expression Array 230 2.0 (3' IVT Expression Analysis). Statistical analyses of the microarray data were performed using R statistical package (version 2.8.1).

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Transcription profiling of rat livers after treatment with control, BNF, D3T, and OLT

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