Unknown,Transcriptomics,Genomics,Proteomics

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Transcription profiling of rat livers of rats control, D3T, OLT, or TBD

ABSTRACT: 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.

ORGANISM(S): Rattus norvegicus

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PROVIDER: E-GEOD-8882 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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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).

Project description:Through substitution mapping studies, we previously identified that a <330kb region from a rat strain with no renal pathology (the Lewis rat), which when introgressed onto the genetic background of a rat with renal disease (the Dahl Salt-sensitive (S) rat), caused an increase rather than the expected decrease in proteinuria. The purpose of this study was to prioritize a candidate gene and further delineate the mechanism underlying the observed increased in proteinuria. A higher level of proteinuria independent of dietary salt was observed in the congenic rat at a very young age (50-52 day old). The critical congenic segment was further mapped to <42.5kb containing a single candidate gene, rififylin. Rififylin was expressed 1.59 fold higher in the congenic strain compared with S. Overexpression of rififylin is known to delay recycling of endosomes. Renal transcriptome analysis indicated that Atp1a1 one of the most highly differentially expressed genes. Atp1a1 was 5.33 fold higher in the congenic strain compared with S. The protein product of Atp1a1, the alpha subunit of Na+K+ATPase, was also significantly higher in the endosomes of proximal tubules from the congenic strain compared with S. To determine whether the higher amounts of this protein in the endosomes is due to a delay in recycling of endosomes caused by the overexpression of rififylin in the congenic strain, recycling of exogenously labeled-transferrin by single cell cultures of proximal tubules was monitored by confocal microscopy. Recycling of transferrin was significantly delayed in the congenic strain compared with S. These results suggest that impaired endosomal recycling in the proximal tubules from the congenic strain caused by the overexpression of rififylin is a novel molecular mechanism linked to the observed increase in proteinuria of the congenic strain. Three male S control and 3 male congenic S.LEW(10)x12x2x3x5 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 low-salt (0.3%) 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 each animal was 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 with BH adjustment using R statistical package (version 2.8.1).

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Transcription profiling of rat livers of rats control, D3T, OLT, or TBD

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