Many forms of synaptic plasticity are critically dependent upon production of cGMP to trigger activity-dependent increases in synaptic size and strength. Phosphodiesterase 9A (PDE9A) is a high affinity, cGMP-specific phosphodiesterase with widespread distribution in the central nervous system. Inhibition of PDE9A results in significant accumulation of cGMP in brain tissue and cerebrospinal fluid (CSF) of rodents, and increases CSF cGMP in human volunteers. We hypothesized that chronic exposure to a PDE9A inhibitor, and the associated elevations in brain cGMP could provide a therapeutic benefit to vulnerable synapses chronically exposed to A in transgenic mice over-expressing human mutant amyloid precursor protein (Tg2576 mice). A total of N=20 animals per group of 4 month old Tg2576 mice and non-transgenic littermates (WT) were implanted with Alzet osmotic minipumps to deliver vehicle or the PDE9A inhibitor PF-04447943. Neurobehavioral outcomes were measured as conditioned fear response after 28 days of treatment and subsequently brains were harvested for measurement of A, gene expression profiling or synaptic density as assessed by Golgi staining of dendrites. Dendritic spine density on apical dendrites of CA1 neurons exhibited a small but significant deficit in the density of dendritic spines in vehicle treated Tg2576 mice as compared to WT mice. This deficit was ameliorated by 30 days of exposure to PF-04447943. No significant drug effect was observed in WT mice. No significant effects of drug treatment were observed on A levels in Tg2576 mice. Behavioral analysis of Tg2576 mice showed deficits in fear conditioning as early as 2 months old, and therefore were considered unlikely to be due to the accumulation of oligomeric A. These deficits were not affected by drug treatment. Transcriptional profiles of Tg2576 mice treated with drug compared to vehicle showed evidence of regulation of pathways related to synaptic plasticity and remodeling of the dendritic cytoskeleton, consistent with stabilization of vulnerable spine structure. These data supports the hypothesis that PDE9A inhibition can stabilize vulnerable synapses early in the Alzheimers disease process.
No associated publication
Age, Specimen part
View SamplesThe nuclear receptor PPARalpha is recognized as the primary target of the fibrate class of hypolipidemic drugs and mediates lipid lowering in part by activating a transcriptional cascade that induces genes involved in the catabolism of lipids. We report here the characterization of three novel PPARalpha agonists with therapeutic potential for treating dyslipidemia. These structurally related compounds display potent and selective binding to human PPARalpha and support robust recruitment of coactivator peptides in vitro. These compounds markedly potentiate chimeric transcription systems in cell-based assays and strikingly lower serum triglycerides in vivo. The transcription networks induced by these selective PPARalpha agonists were assessed by transcriptional profiling of mouse liver after acute and chronic treatment. The induction of several known PPARalpha target genes involved with fatty acid metabolism were observed, reflecting the expected pharmacology associated with PPARalpha activation. We also noted the downregulation of a number of genes related to immune cell function, the acute phase response, and glucose metabolism; suggesting that these compounds may have anti-inflammatory action in the mammalian liver. Taken together, these studies articulate the therapeutic promise of a selective PPARalpha agonist.
Molecular characterization of novel and selective peroxisome proliferator-activated receptor alpha agonists with robust hypolipidemic activity in vivo.
No sample metadata fields
View SamplesThere are an estimated 21million diabetics in the United States and 150 million diabetics worldwide. The World Health Organization anticipates that these numbers will double in the next 20 years. Metabolic syndrome is a well recognized set of symptoms that increases a patients risk of developing diabetes. Insulin resistance is a factor in both metabolic syndrome and Type 2 diabetes. It is characterized by decreased insulin stimulated glucose uptake in peripheral tissues, decreased adiponectin levels, increased adipocyte FFA and cytokine production, and increased insulin and hepatic glucose output. Prevention or reversal of insulin resistance should serve as an important strategy in addressing the growing health concerns posed by the Diabetes epidemic. While increased adiposity is associated with insulin resistance, the role of the cell types present within adipose (adipocytes, pre-adipocytes, endothelial cells, macrophages, fibroblasts, leukocytes and smooth muscle cells) in insulin resistance is unclear. In an effort to begin dissection of this question, we examined the transcriptional response of the buoyant and non-buoyant fractions isolated from insulin sensitive or TNF induced insulin resistant hMSC derived adipocytes before and after treatment with insulin.
Genome-wide profiling of H3K56 acetylation and transcription factor binding sites in human adipocytes.
Specimen part
View Samples3 Cell lines from Apc, p53 (AP) GEMMs were compared to 12 cell lines from Apc, Kras, p53 (AKP) GEMMs.
Development of a colon cancer GEMM-derived orthotopic transplant model for drug discovery and validation.
Sex, Cell line
View SamplesCurrent approaches to the preclinical investigation for novel cancer therapies rely heavily on the use of traditional cancer cell lines maintained in serum-containing conditions. The discrepancy between promising preclinical efficacy and clinical outcome of most novel anticancer agents emphasizes a need for developing predictive preclinical models that preserve the integrity of original patient tumors, including cancer stem cell (CSC) compartment.
No associated publication
Cell line
View SamplesDysregulation of ceramide synthesis has been associated with metabolic disorders such as atherosclerosis and diabetes mellitus. Using a human hepatoma cell line (Huh7), we investigated the changes in lipid homeostasis and gene expression when the synthesis of ceramide is perturbed by knocking down serine transferases subunits 1, 2 and 3 (SPTLC123) or dihydroceramide desaturase (DEGS1). While the inhibition of serine palmitoyl transferase (SPTLC) affects ceramide production differently at the subspecies level depending upon which SPTLC subunit is silenced; depleting DEGS1 is sufficient to produce a similar outcome as knocking down all SPTLC subunits. Both the distribution of multiple lipid classes, especially at the subspecies level, and the global transcriptional profile is altered differently when either SPTLC123 or DEGS1 were silenced. The overall transcriptional changes indicate a negative regulation in biosynthetic processes and a down-regulation of genes involved in general endomembrane trafficking for both DEGS1 and SPTLC123 siRNA treated cells, but also the up-regulation of genes involved with cell migration function in DEGS1 siRNA cells. Pathway analysis indicate changes in amino acid, sugar and nucleotide metabolisms as well as vesicle trafficking between organelles occurred more robustly in DEGS1 silenced cells. Although either SPTLC123 or DEGS1 siRNA treatment positively regulated numerous genes involved with endocytosis and endosomal recycling, depleting SPTLC123 caused transcriptional changes in genes primarily involved with lipid metabolism. The alterations reflect how SPTLC or DEGS1 silenced cells respond differently to disruption in lipid flux, but also maintain cellular lipid pools through increasing endocytotic processes and down-regulating metabolic biosynthesis without developing endoplasmic reticulum stress. Also, these results are the first to demonstrate that reducing ceramide synthesis by decreasing the function of either SPTLC or DEGS1 affects cellular function differently at the level of lipid synthesis and gene expression.
Silencing of enzymes involved in ceramide biosynthesis causes distinct global alterations of lipid homeostasis and gene expression.
Cell line
View SamplesGene expression and copy number variation arrays for parental GTL16 and GTL16 clones resistant to c-Met inhibitor.
A novel SND1-BRAF fusion confers resistance to c-Met inhibitor PF-04217903 in GTL16 cells through [corrected] MAPK activation.
Cell line
View SamplesA large, prospective, non-interventional study was designed to study gene expression changes in peripheral blood mononuclear cells (PBMCs) associated with asthma exacerbations over the course of a year. PBMC samples were collected from subjects at the time of the study visits defined as 1) Quiet: during stable disease at 3 month intervals, 2) Exacerbation: during a 14 day period of deteriorating asthma and 3) Follow-up: within 14 days after cessation of an exacerbation. Gene expression levels during stable asthma, exacerbation, and two weeks after an exacerbation were compared.
Pathways activated during human asthma exacerbation as revealed by gene expression patterns in blood.
Specimen part, Race
View SamplesSchizophrenia is a complex psychiatric disorder encompassing a range of symptoms and etiology dependent upon the interaction of genetic and environmental factors. Several risk genes, such as DISC1, have been associated with schizophrenia as well as bipolar disorder (BPD) and major depressive disorder (MDD), consistent with the hypothesis that a shared genetic architecture could contribute to divergent clinical syndromes. The present study compared gene expression profiles across three brain regions in post-mortem tissue from matched subjects with schizophrenia, BPD or MDD and unaffected controls. Post-mortem brain tissue was collected from control subjects and well-matched subjects with schizophrenia, BPD, and MDD (n=19 from each group). RNA was isolated from hippocampus, Brodmann Area 46, and associative striatum and hybridized to U133_Plus2 Affymetrix chips. Data were normalized by RMA, subjected to pairwise comparison followed by Benjamini and Hochberg False Discovery Rate correction (FDR). Samples derived from patients with schizophrenia exhibited many more changes in gene expression across all brain regions than observed in BPD or MDD. Several genes showed changes in both schizophrenia and BPD, though the magnitude of change was usually larger in schizophrenia. Several genes that have variants associated with schizophrenia were found to have altered expression in multiple regions of brains from subjects with schizophrenia. Continued evaluation of circuit-level alterations in gene expression and gene-network relationships may further our understanding of how genetic variants may be influencing biological processes to contribute to psychiatric disease.
STEP levels are unchanged in pre-frontal cortex and associative striatum in post-mortem human brain samples from subjects with schizophrenia, bipolar disorder and major depressive disorder.
Sex, Age, Specimen part, Disease, Disease stage, Race
View SamplesThis series of samples comprises multiple early embryonic time courses for C. elegans. Time courses consisting of 10 time points each for 4 different genotypes are included: wild-type (strain N2 grown on E. coli strain OP50), pie-1(zu154) (progeny of homozygous mutant mothers [Unc] of strain JJ532 grown on E. coli strain OP50), pie-1(zu154);pal-1(RNAi) (progeny of homozygous mutant mothers [Unc] of strain JJ532 grown on E. coli strain HT115 expressing pal-1 hairpin RNA), and mex-3(zu155);skn-1(RNAi) (progeny of homozygous mutant mothers [Dpy] of strain JJ518 grown on E. coli strain HT115 expressing skn-1 hairpin RNA). Embryos were manually staged by morphology at the 4-cell stage and allowed to develop in water for defined amounts of time at 22 degrees C. RNA was amplified as described (Baugh et al. Development, 2003; Baugh et al. Nucleic Acids Research, 2001). This series of samples comprises all replicate data reported by Baugh et al. (Development, 2005).
The homeodomain protein PAL-1 specifies a lineage-specific regulatory network in the C. elegans embryo.
No sample metadata fields
View Samples