Mdr1a-, Bcrp-, and Mrp2-knockout rats are a more practical species for ADME studies than murine models and previously demonstrated expected alterations in pharmacokinetics of various probe substrates. At present, gene expression and pathology changes were systematically studied in small intestine, liver, kidney, and brain tissue from male SAGE Mdr1a-, Bcrp-, and Mrp2-knockout rats versus wild-type Sprague Dawley controls. Gene expression data supported the relevant knockout genotype. As expected, Mrp2-knockout rats were hyperbilirubinemic and exhibited upregulation of hepatic Mrp3. Overall, few alterations were observed within 137 ADME-relevant genes. The two most consequential changes were upregulation of intestinal carboxylesterase in Mdr1a-knockouts and catechol-O-methyltransferase in all tissues of Bcrp-knockout rats. Previously reported upregulation of hepatic Mdr1b P-glycoprotein in proprietary Wistar Mdr1a-knockout rats was not observed in the SAGE counterpart investigated herein. Relative liver and kidney weights were 22-53% higher in all three knockouts, with microscopic increases in hepatocyte size in Mdr1a- and Mrp2-knockout rats, and glomerular size in Bcrp- and Mrp2-knockouts. Increased relative weight of clearing organs is quantitatively consistent with reported increases in clearance of drugs that are not substrates of the knocked-out transporter. Overall, SAGE knockout rats demonstrated modest compensatory changes, which do not preclude their general application to study transporter-mediated pharmacokinetics. However until future studies elucidate the magnitude of functional change, caution is warranted in rare instances of extensive metabolism by catechol-O-methyltransferase in Bcrp-knockouts and intestinal carboxylesterase in Mdr1a-knockout rats, specifically for molecules with free catechol groups and esters subject to gut wall hydrolysis.
Minor compensatory changes in SAGE Mdr1a (P-gp), Bcrp, and Mrp2 knockout rats do not detract from their utility in the study of transporter-mediated pharmacokinetics.
Sex, Specimen part
View SamplesThe project had 2 goals:
Pooling samples within microarray studies: a comparative analysis of rat liver transcription response to prototypical toxicants.
No sample metadata fields
View SamplesDespite investment in toxicogenomics, nonclinical safety studies are still used to predict clinical liabilities for new drug candidates. Network-based approaches for genomic analysis help overcome challenges with whole-genome transcriptional profiling using limited numbers of treatments for phenotypes of interest. Herein, we apply co-expression network analysis to safety assessment using rat liver gene expression data to define 415 modules, exhibiting unique transcriptional control, organized in a visual representation of the transcriptome (the TXG-MAP). Accounting for the overall transcriptional activity resulting from treatment, we explain mechanisms of toxicity and predict distinct toxicity phenotypes using module associations. We demonstrate that early network responses compliment traditional histology-based assessment in predicting outcomes for longer studies and identify a novel mechanism of hepatotoxicity involving endoplasmic reticulum stress and Nrf2 activation. Module-based molecular subtypes of cholestatic injury derived using rat translate to human. Moreover, compared to gene-level analysis alone, combining module and gene-level analysis performed in sequence identifies significantly more phenotype-gene associations, including established and novel biomarkers of liver injury.
Toxicogenomic module associations with pathogenesis: a network-based approach to understanding drug toxicity.
Sex, Specimen part
View SamplesThe discovery of mammalian cardiac progenitor cells has suggested that the heart consists of not only terminally differentiated beating cardiomyocytes, but also a population of self-renewing stem cells with the potential to generate new cardiomyocytes (Anderson, Self et al. 2007; Bearzi, Rota et al. 2007; Wu, Chien et al. 2008). A consequence of longevity is continual exposure to environmental and xenobiotic stresses, and recent literature suggests that hematopoietic stem cell pools tightly control cell health through upregulation of the integrated stress response and consequent cellular mechanisms such as apoptosis. However, whether or not this biological response is conserved in progenitor cells for later lineages of tissue specific stem cells is not well understood. Using human induced pluripotent stem cells (iPSC) of both cardiac progenitor and mature cardiomyocyte lineages, we found that the integrated stress response was upregulated in the iPSC cardiac progenitors leading to an increased sensitivity for apoptosis relative to the mature cardiomyocytes. Of interest, C/EBP homologous protein (CHOP) signaling plays a mechanistic role in the cell death phenotype observed in iPSC progenitors, by which depletion of CHOP prevents cell death following cellular stress by thapsigargin exposure. Our studies suggest that the integrated stress response plays a unique role in maintaining iPSC cardiac progenitor cellular integrity by removing unhealthy cells via apoptosis following environmental and xenobiotic stresses, thus preventing differentiation and self-renewal of damaged cells.
The Integrated Stress Response Regulates Cell Health of Cardiac Progenitors.
Specimen part, Treatment
View SamplesHigh regenerative capacity of adult skeletal muscle relies on a self-renewing depot of adult stem cells, termed muscle satellite cells (MSCs). A novel MSC line was isolated from the rat levator ani muscle and termed Levator Ani Satellite Cells (LASCs).
No associated publication
Specimen part
View SamplesAnalysis of gene expression profiles of epididymal fat from DIO rats
Assessment of diet-induced obese rats as an obesity model by comparative functional genomics.
No sample metadata fields
View SamplesObjective: Systemic lupus erythematosus (SLE) has substantial unmet medical need and its pathogenesis is incompletely understood. This study characterized baseline gene expression and pharmacodynamic (PD)-induced changes in whole blood gene expression from two phase III, 52-week (W), randomized, placebo-controlled, double-blind studies of 1,760 SLE patients treated with the B cell activating factor (BAFF)-blocking IgG4 monoclonal antibody, tabalumab. Methods: Patient samples were obtained from ILLUMINATE-1 and -2 while control samples were from healthy donors. Blood was collected in TempusTM tubes at baseline, W16 and W52. RNA was analyzed using the Affymetrix Human Transcriptome Array 2.0 and NanoStringTM. Results: At baseline there was elevation of interferon responsive genes (IRG) in patients compared to controls, with 75% positive for this IRG signature. There was, however, substantial heterogeneity of IRG expression and complex relationships among gene networks. The interferon signature was a predictor of future time to flare, independent of anti-double stranded DNA antibody (dsDNA), C3 and C4 levels, and overall disease activity. PD changes in gene expression following tabalumab treatment were extensive, occurring predominantly in B cell-related and immunoglobulin (Ig) genes, and were consistent with other PD-induced changes including dsDNA, C3, and Ig levels. Conclusions: SLE patients demonstrated elevated expression of an IRG signature, detected in 75% of the patients at baseline in ILLUMINATE-1 and -2. There was substantial heterogeneity of gene expression detected among individual patients and in gene networks. The interferon signature was an independent risk factor for future flares. PD changes in gene expression were consistent with the mechanism of BAFF blockade by tabalumab.
Gene Expression and Pharmacodynamic Changes in 1,760 Systemic Lupus Erythematosus Patients From Two Phase III Trials of BAFF Blockade With Tabalumab.
Sex, Specimen part, Race, Subject, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Gene Expression and Pharmacodynamic Changes in 1,760 Systemic Lupus Erythematosus Patients From Two Phase III Trials of BAFF Blockade With Tabalumab.
Sex, Specimen part, Race, Subject, Time
View SamplesObjective: Systemic lupus erythematosus (SLE) has substantial unmet medical need and its pathogenesis is incompletely understood. This study characterized baseline gene expression and pharmacodynamic (PD)-induced changes in whole blood gene expression from two phase III, 52-week (W), randomized, placebo-controlled, double-blind studies of 1,760 SLE patients treated with the B cell activating factor (BAFF)-blocking IgG4 monoclonal antibody, tabalumab. Methods: Patient samples were obtained from ILLUMINATE-1 and -2 while control samples were from healthy donors. Blood was collected in TempusTM tubes at baseline, W16 and W52. RNA was analyzed using the Affymetrix Human Transcriptome Array 2.0 and NanoStringTM. Results: At baseline there was elevation of interferon responsive genes (IRG) in patients compared to controls, with 75% positive for this IRG signature. There was, however, substantial heterogeneity of IRG expression and complex relationships among gene networks. The interferon signature was a predictor of future time to flare, independent of anti-double stranded DNA antibody (dsDNA), C3 and C4 levels, and overall disease activity. PD changes in gene expression following tabalumab treatment were extensive, occurring predominantly in B cell-related and immunoglobulin (Ig) genes, and were consistent with other PD-induced changes including dsDNA, C3, and Ig levels. Conclusions: SLE patients demonstrated elevated expression of an IRG signature, detected in 75% of the patients at baseline in ILLUMINATE-1 and -2. There was substantial heterogeneity of gene expression detected among individual patients and in gene networks. The interferon signature was an independent risk factor for future flares. PD changes in gene expression were consistent with the mechanism of BAFF blockade by tabalumab.
Gene Expression and Pharmacodynamic Changes in 1,760 Systemic Lupus Erythematosus Patients From Two Phase III Trials of BAFF Blockade With Tabalumab.
Sex, Specimen part, Race, Subject, Time
View SamplesObjective: Systemic lupus erythematosus (SLE) has substantial unmet medical need and its pathogenesis is incompletely understood. This study characterized baseline gene expression and pharmacodynamic (PD)-induced changes in whole blood gene expression from two phase III, 52-week (W), randomized, placebo-controlled, double-blind studies of 1,760 SLE patients treated with the B cell activating factor (BAFF)-blocking IgG4 monoclonal antibody, tabalumab. Methods: Patient samples were obtained from ILLUMINATE-1 and -2 while control samples were from healthy donors. Blood was collected in TempusTM tubes at baseline, W16 and W52. RNA was analyzed using the Affymetrix Human Transcriptome Array 2.0 and NanoStringTM. Results: At baseline there was elevation of interferon responsive genes (IRG) in patients compared to controls, with 75% positive for this IRG signature. There was, however, substantial heterogeneity of IRG expression and complex relationships among gene networks. The interferon signature was a predictor of future time to flare, independent of anti-double stranded DNA antibody (dsDNA), C3 and C4 levels, and overall disease activity. PD changes in gene expression following tabalumab treatment were extensive, occurring predominantly in B cell-related and immunoglobulin (Ig) genes, and were consistent with other PD-induced changes including dsDNA, C3, and Ig levels. Conclusions: SLE patients demonstrated elevated expression of an IRG signature, detected in 75% of the patients at baseline in ILLUMINATE-1 and -2. There was substantial heterogeneity of gene expression detected among individual patients and in gene networks. The interferon signature was an independent risk factor for future flares. PD changes in gene expression were consistent with the mechanism of BAFF blockade by tabalumab.
Gene Expression and Pharmacodynamic Changes in 1,760 Systemic Lupus Erythematosus Patients From Two Phase III Trials of BAFF Blockade With Tabalumab.
Sex, Specimen part, Race, Subject, Time
View Samples