AD drug discovery has rarely been addressed in the context of aging even though sporadic AD accounts for 99% of the cases. Phenotypic screens based upon old age-associated brain toxicities were used to develop the potent AD drug candidate J147. Here, we hypothesized that J147 would be effective against both brain aging and AD-associated pathology in rapidly aging SAMP8 mice, a model for early sporadic AD. An inclusive and integrative multi-omics approach was used to investigate protein expression, RNA expression, metabolite levels as well as cognition in old and young SAMP8 mice. J147 not only reduced the cognitive deficits and associated metabolic changes observed in old SAMP8 mice, it restored the levels of multiple markers of AD, vascular pathology, synaptic function, and inflammation to those approaching the young phenotype. Our data show that a drug candidate selected upon the basis of preventing old age-related brain toxicities also reduces AD-associated pathology. Overall design: The aim of this project was to investigate whether the AD drug candidate J147 protects SAMP8 mice from aging and AD-associated pathology and to assay the associated metabolic changes. Three three-month old male SAMP8 mice were fed with vehicle diet and three three-month old male SAMP8 mice with J147 diet until they reached ten months old. Four three-month old male SAMP8 mice were used as young control group.
A comprehensive multiomics approach toward understanding the relationship between aging and dementia.
No sample metadata fields
View SamplesHuman medulloblastoma (MB) can be segregated into four major categories based on gene expression patterns: Hedgehog (HH) subtype, Wnt subtype, Group 3, and Group 4. However, they all exhibit strikingly different gene expression profiles from Atypical Teratoid/Rhabdoid Tumor (AT/RT). We re-analyzed published gene expression microarray dataset of pediatric brain tumors to identify a gene expression profile that clearly distinguished human AT/RT from human MB. We used this profile, choosing only genes that have clear murine orthologs, to compare tumors from Snf5F/Fp53L/LGFAP-Cre mice (in C57Bl/6 strain background) with MB from Ptc1+/- mice (in mixed C57Bl/6 and 129Sv strain background). Snf5F/Fp53L/LGFAP-Cre tumors are clearly very different from mouse MB and the markers that distinguish human AT/RT from human MB also distinguish the mouse tumors.
Generation of a mouse model of atypical teratoid/rhabdoid tumor of the central nervous system through combined deletion of Snf5 and p53.
No sample metadata fields
View SamplesPKR is an interferon induced serine/threonine protein kinase, that is activated by double stranded RNA. PKR plays an important role in the antiviral defense by interferon. In addition to its role in translation, PKR participates in several signaling pathways to transcription. The goal of this experiment is to study the role of PKR in regulating gene expression in our NIH 3T3 inducible cell line, which could overexpress PKR wt protein after the removal of tetracycline (Donze O, Dostie J, Sonenberg N. (1999) Virology 256: 322-9).
The protein kinase PKR: a molecular clock that sequentially activates survival and death programs.
Cell line
View SamplesWhole blood (paxgene) gene expression was measured using Affymetrix microarray from 377 individuals with rheumatoid arthritis.
Integrative genomic deconvolution of rheumatoid arthritis GWAS loci into gene and cell type associations.
Sex, Age, Specimen part, Disease
View SamplesAlthough glucocorticoids (GCs) are known to exert numerous effects in the hippocampus, their chronic regulatory functions remain poorly understood. Moreover, evidence is inconsistent regarding the longstanding hypothesis that chronic GC exposure promotes brain aging/Alzheimer's disease. Here, we adrenalectomized male F344 rats at 15-months-of-age, maintained them for 3 months with implanted corticosterone (CORT) pellets producing low or intermediate (glucocorticoid-receptor (GR)-activating) blood levels of CORT, and performed microarray/pathway analyses in hippocampal CA1. We defined the chronic GC-dependent transcriptome as 393 genes that exhibited differential expression between Intermediate- and Low-CORT groups. Short-term CORT (4 days) did not recapitulate this transcriptome. Functional processes/pathways overrepresented by chronic CORT-upregulated genes included learning/plasticity, differentiation, glucose metabolism and cholesterol biosynthesis, whereas processes overrepresented by CORT-downregulated genes included inflammatory/immune/glial responses and extracellular structure. These profiles indicate that GCs chronically activate neuronal/metabolic processes while coordinately repressing a glial axis of reactivity/inflammation. We then compared the GC-transcriptome with a previously-defined hippocampal aging transcriptome, revealing a high proportion of common genes. Although CORT and aging moved expression of some common genes in the same-direction, the majority were shifted in opposite directions by CORT and aging (e.g., glial inflammatory genes downregulated by CORT are upregulated with aging). These results contradict the hypothesis that GCs simply promote brain aging, and also suggest that the opposite-direction shifts during aging reflect resistance to CORT regulation. Therefore, we propose a new model in which aging-related GC resistance develops in some target pathways while GC overstimulation develops in others, together generating much of the brain aging phenotype.
Glucocorticoid-dependent hippocampal transcriptome in male rats: pathway-specific alterations with aging.
Sex, Age, Specimen part
View SamplesRecent data suggests that common genetic risk for metabolic disorders such as obesity may be human-specific and exert effects through the central nervous system. To overcome the limitation of human tissue access for study, we have generated induced human pluripotent stem cell (hiPSC)- derived neuronal cultures which recapture many features of hypothalamic neurons within the arcuate nucleus. Here we have comprehensively characterized this model across development and benchmarked these neurons to in vivo events. We also demonstrate their utility in study of obesity risk variants. The dynamic transcriptome across neuronal maturation was examined using microarray and RNAseq methods at 9 time points. K-means clustering of the longitudinal data was conducted to identify co-regulation and miRNA control of biological processes. The transcriptomes were compared to those of 103 samples from 13 brain regions reported in the Genotype-Tissue Expression database (GTEx) using principal components analysis. Genes with proximity to body mass index (BMI)-associated genetic variants were mapped to the developmentally expressed genesets, and enrichment significance was assessed with Fishers exact test. The human neuronal cultures have a transcriptional and physiological profile of NPY/AgRP hypothalamic neurons. The neuronal transcriptomes were highly correlated with adult hypothalamus as compared to any other brain region from the GTEx. Also, roughly 25% of the transcripts showed changes in expression across maturation stages and potential co-regulation of biological processes that mirror neuronal development in vivo. These developmentally expressed genes were significantly enriched for genes in proximity to BMI-associated variants.
Molecular Profiling of Human Induced Pluripotent Stem Cell-Derived Hypothalamic Neurones Provides Developmental Insights into Genetic Loci for Body Weight Regulation.
Specimen part
View SamplesSequencing of total RNA and polysomal RNA of two cell lines, MCF7 (tumoral) and MCF10A (non-tumoral) Overall design: Polysomal and total RNA was prepared from biological triplicates from the two cell lines. For each biological triplicate sub-confluent cell monolyers were lysed to produce cytoplasmic extracts. Half of each extract was fractionated on a sucrose gradient and the polysomal fraction recovered. Polysomal-associated RNA was recovered by Trizol extraction. From the second half of each sample total cyoplasmic RNA was recovered (Trizol extraction).
The effect of heterogeneous Transcription Start Sites (TSS) on the translatome: implications for the mammalian cellular phenotype.
No sample metadata fields
View SamplesThe intermediate filament protein Nestin serves as a biomarker for stem cells and has been used to identify subsets of cancer stem-like cells. However, the mechanistic contributions of Nestin to cancer pathogenesis are not understood. Here we report that Nestin binds the hedgehog pathway transcription factor Gli3 to mediate the development of medulloblastomas of the hedgehog subtype. In a mouse model system, Nestin levels increased progressively during medulloblastoma formation resulting in enhanced tumor growth. Conversely, loss of Nestin dramatically inhibited proliferation and promoted differentiation. Mechanistic investigations revealed that the tumor-promoting effects of Nestin were mediated by binding to Gli3, a zinc finger transcription factor that negatively regulates hedgehog signaling. Nestin binding to Gli3 blocked Gli3 phosphorylation and its subsequent proteolytic processing, thereby abrogating its ability to negatively regulate the hedgehog pathway. Our findings show how Nestin drives hedgehog pathway-driven cancers and uncover in Gli3 a therapeutic target to treat these malignancies.
Nestin Mediates Hedgehog Pathway Tumorigenesis.
Specimen part
View SamplesThe LH surge triggers dramatic transcriptional changes in genes associated with ovulation and luteinization. The present study investigated the spatiotemporal expression of nuclear factor interleukin-3 (NFIL3), a transcriptional regulator of the bZIP transcription factor superfamily, and its potential role in the ovary during the periovulatory period. NFIL3, also known as E4-binding protein 4 or NFIL3/E4BP4, was originally identified as a transcriptional repressor based on its DNA-binding activity at the promoter of the gene encoding the adenovirus E4 protein. Immature female rats were injected with PMSG, treated with hCG, and ovaries or granulosa cells were collected at various times after hCG. Nfil3 mRNA was highly induced both in intact ovaries and granulosa cells after hCG treatment. In situ hybridization demonstrated that Nfil3 mRNA was highly induced in theca-interstitial cells at 4-8 h after hCG, localized to granulosa cells at 12 h, and decreased at 24 h. Over-expression of NFIL3 in granulosa cells inhibited the induction of prostaglandin-endoperoxide synthase 2 (Ptgs2), progesterone receptor (Pgr), epiregulin (Ereg), and amphiregulin (Areg) and down regulated levels of prostaglandin E2. The inhibitory effect on Ptgs2 induction was reversed by NFIL3 siRNA treatment. In theca-interstitial cells the expression of hydroxyprostaglandin dehydrogenase 15-(NAD) (Hpgd) was also inhibited by NFIL3 over-expression. Data from luciferase assays demonstrated that NFIL3 over-expression decreased the induction of the Ptgs2 and Areg promoter activity. EMSA and ChIP analyses indicated that NFIL3 binds to the promoter region containing the DNA binding sites of CREB and C/EBP?. In summary, hCG induction of NFIL3 expression may modulate the process of ovulation and theca-interstitial and granulosa cell differentiation by regulating expression of PTGS2, PGR, AREG, EREG, and HPGD, potentially through interactions with CREB and C/EBP? on their target gene promoters.
A role for nuclear factor interleukin-3 (NFIL3), a critical transcriptional repressor, in down-regulation of periovulatory gene expression.
Sex
View SamplesSleep deprivation (SD) in young adults is associated with metabolic, stress and cognitive responses that are also characteristic of brain aging. Given that sleep architecture changes with age, including increased fragmentation and decreased slow wave activity, it seems reasonable to investigate potential molecular relationships between SD and aging in brain tissue. Here, we tested the hypothesis that young rats exposed to 24 or 72 hour SD would respond with stress and aging-like shifts in brain hippocampal CA1 gene expression. SD animals showed blood corticosterone and weight changes consistent with a stress response. Microarray results, validated by Western blot and comparison to prior SD studies, pointed to disruptions in neurotransmission, sleep pressure signaling, and macromolecular synthesis. In a separate experiment, animals exposed to 24 or 72 hour novel environment stress recapitulated nearly one third of the SD transcriptional profile, particularly upregulated apoptotic and immune signaling pathways. Compared to aging (based on three previously published independent hippocampal aging studies), SD transcriptional profiles agreed for neurogenesis and energy pathways. However, immune signaling, glial activity, macromolecular synthesis and neuronal function all showed an SD profile that was, at least in part, opposed by aging. We conclude that while stress and SD have discrete molecular signatures, they do show a subset of highly similar changes. However, the same could not be said of aging and SD, where a similar subset of genes is changed, but in partially divergent directions. Finally, this work identifies presynaptic vesicular release and intercellular adhesion molecular signatures as novel targets for future SD-countering therapeutics.
Hippocampal CA1 transcriptional profile of sleep deprivation: relation to aging and stress.
Sex, Treatment
View Samples