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GSE76012
Rattus norvegicus
12 Downloadable Samples
Affymetrix Rat Genome 230 2.0 Array (rat2302)
Description
Though obesity is a global epidemic, the physiological mechanisms involved are little understood. Recent advances reveal that susceptibility to obesity can be programmed by maternal and neonatal nutrition. Specifically, a maternal low protein diet during pregnancy causes decreased intrauterine growth, rapid postnatal catch-up growth and increased risk for diet-induced obesity. Given that the synthesis of the neurotransmitter 5-hydroxytryptamine (5-HT) is nutritionally regulated and 5-HT is a trophic factor, we hypothesized that maternal diet influences fetal 5-HT exposure, which then influences central appetite network development and the subsequent efficacy of 5-HT to control energy balance in later life. Consistent with our hypothesis, pregnant low protein fed rat mothers exhibited elevated serum 5-HT, which was also evident in the placenta and fetal brains at E16.5. This increase was associated with reduced hypothalamic expression of 5-HT2CR - the primary 5-HT receptor influencing appetite. As expected, reduced 5-HT2CR expression was associated with impaired sensitivity to 5-HT-mediated appetite suppression. 5-HT primarily achieves effects on appetite via 5-HT2CR stimulation of pro-opiomelanocortin (POMC) peptides within the arcuate nucleus of the hypothalamus (ARC). We reveal that 5-HT2ARs are also anatomically positioned to influence the activity of ARC POMC and that 5-HT2AR mRNA is increased in the hypothalamus of in utero growth restricted offspring that underwent rapid postnatal catch-up growth. Furthermore, these animals are more sensitive to 5-HT2AR agonist-induced appetite suppression. These findings may not only reveal a 5-HT-mediated mechanism underlying programming of obesity susceptibility but also provide a promising means to correct it, via a 5-HT2AR agonist treatment.
Publication Title
5-HT2A and 5-HT2C receptors as hypothalamic targets of developmental programming in male rats.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 15 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
We identified secreted frizzled-related protein-5 (Sfrp5) as a transcript that is upregulated during adipocyte differentiation and that is increased in white adipose tissue (WAT) of obese mice, compared to lean mice. To investigate the function of sFRP5 in adipose tissue biology, we studied sFRP5Q27stop mice, in which ENU mutagenesis was used to create a premature stop codon at Gln27, thereby creating a likely null allele.
Publication Title
Secreted frizzled-related protein 5 suppresses adipocyte mitochondrial metabolism through WNT inhibition.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Homo sapiens
- 14 Downloadable Samples
- Illumina HumanRef-8 v3.0 expression beadchip
Description
The molecular mechanisms underlying the development of bone metastases in breast cancer remain unclear. Disseminated tumour cells (DTCs) in the bone marrow of breast cancer patients are commonly identified, even in early stage disease, but their potential to initiate metastases is not known. The mechanism whereby DTCs become overt metastatic tumour cells (MTCs) is therefore, an area of considerable interest. This study explored the analysable yield of genetic material from human biopsy samples in order to describe differences in gene expression between DTCs and bone MTCs. Thirteen breast cancer patients with bone metastases underwent a CT-guided bone metastasis biopsy and a bone marrow biopsy. Tumour cells were enriched and gene expression profiling was conducted to identify differentially expressed genes. The analysable yield of sufficient RNA for microarray analysis was 60% from bone metastasis biopsies and 80% from bone marrow biopsies. A signature of 133 candidate genes differentially expressed between DTCs and MTCs was identified. Several genes relevant to breast cancer metastasis to bone (osteopontin, CTGF, parathyroid hormone receptor, EGFR) were significantly overexpressed in MTCs as compared to DTCs. Biopsies of bone metastases and bone marrow rarely yield enough tissue for robust molecular biology studies using clinical samples. The findings obtained however are interesting and seem to overlap with the bone metastasis gene expression signature described in murine xenograft models. Larger biopsy specimens or improved RNA extraction techniques may improve analysable yield and feasibility of these techniques.
Publication Title
Mechanisms and pathways of bone metastasis: challenges and pitfalls of performing molecular research on patient samples.
Sample Metadata Fields
Specimen part, Disease
View Samples- Mus musculus
- 12 Downloadable Samples
Illumina HiSeq 2500
Description
Despite significant advances in our understanding of the biology determining systemic energy homeostasis, the treatment of obesity remains a medical challenge. Activation of AMP-activated protein kinase (AMPK) has been proposed as an attractive strategy for the treatment of obesity and its complications. AMPK is a conserved, ubiquitously expressed, heterotrimeric serine/threonine kinase whose short-term activation has multiple beneficial metabolic effects. Whether these translate into long-term benefits for obesity and its complications is unknown. Here, we observe that mice with chronic AMPK activation, resulting from mutation of the AMPK ?2 subunit, exhibit ghrelin signalling-dependent hyperphagia, obesity and impaired pancreatic islet insulin secretion. Humans bearing the homologous mutation manifest a congruent phenotype. Our studies highlight that long-term AMPK activation can have adverse metabolic consequences with implications for pharmacological strategies seeking to chronically activate AMPK systemically to treat metabolic disease. Overall design: Transcriptomic profiling of the hypothalamic arcuate nucleus from AMPK ?2 R299Q knock-in mice
Publication Title
Chronic Activation of γ2 AMPK Induces Obesity and Reduces β Cell Function.
Sample Metadata Fields
Specimen part, Cell line, Subject
View Samples- Mus musculus
- 12 Downloadable Samples
- Illumina MouseWG-6 v2.0 expression beadchip
Description
Replicating viruses have broad applications in biomedicine, notably in cancer virotherapy and in the design of attenuated vaccines, however uncontrolled virus replication in vulnerable tissues can give pathology and often restricts the use of potent strains. Increased knowledge of tissue-selective microRNA expression now affords the possibility of engineering replicating viruses that are attenuated at the RNA level in sites of potential pathology, but retain wild type replication activity at sites not expressing the relevant microRNA.
Publication Title
MicroRNA controlled adenovirus mediates anti-cancer efficacy without affecting endogenous microRNA activity.
Sample Metadata Fields
Sex, Age, Specimen part, Treatment
View Samples- Arabidopsis thaliana
- 23 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
The aim of the experiment is to determine sugar and ABA responsive gene expression in Arabidopsis.
Publication Title
Establishing glucose- and ABA-regulated transcription networks in Arabidopsis by microarray analysis and promoter classification using a Relevance Vector Machine.
Sample Metadata Fields
Age, Time
View Samples