Filters
Technology
Platform
GSE21710
Mus musculus
4 Downloadable Samples
Description
Global energy balance in mammals is controlled by the actions of circulating hormones that coordinate fuel production and utilization in metabolically active tissues. Bone-derived osteocalcin, in its undercarboxylated, hormonal form, regulates fat deposition and is a potent insulin secretagogue. Here, we show that insulin receptor (IR) signaling in osteoblasts controls osteoblast development and osteocalcin expression by suppressing the Runx2 inhibitor Twist-2. Mice lacking IR in osteoblasts have low circulating undercarboxylated osteocalcin and reduced bone acquisition due to decreased bone formation and deficient numbers of osteoblasts. With age, these mice develop marked peripheral adiposity and hyperglycemia accompanied by severe glucose intolerance and insulin resistance. The metabolic abnormalities in these mice are improved by infusion of exogenous under-carboxylated osteocalcin. These results indicate the existence of a bone-pancreas endocrine loop through which insulin signaling in the osteoblast ensures osteoblast differentiation and stimulates osteocalcin production, which in turn regulates insulin sensitivity and pancreatic insulin secretion to control glucose homeostasis.
Publication Title
Insulin receptor signaling in osteoblasts regulates postnatal bone acquisition and body composition.
Sample Metadata Fields
Specimen part, Time
View Samples- Mus musculus
- 8 Downloadable Samples
Description
Arx is a paired-box homeodomain transcription factor and the vertebrate ortholog to the Drosophila aristaless (al) gene. Mutations in Arx are associated with a variety of human diseases, including X-linked infantile spasm syndrome (OMIM: 308350), X-linked myoclonic epilepsy with mental retardation and spasticity (OMIM: 300432), X-linked lissencephaly with ambiguous genitalia (OMIM: 300215), X-linked mental retardation 54 (OMIM: 300419), and agenesis of the corpus callosum with abnormal genitalia (OMIM: 300004). Arx-deficient mice exhibit a complex, pleiotrophic phenotype, including decreased proliferation of neuroepithelial cells of the cortex, dysgenesis of the thalamus and olfactory bulbs, and abnormal nonradial migration of GABAergic interneurons. It has been suggested that deficits in interneuron specification, migration, or function lead to loss of inhibitory neurotransmission, which then fails to control excitatory activity and leads to epilepsy or spasticities. Given that Arx mutations are associated with developmental disorders in which epilepsy and spasticity predominate and that Arx-deficient mice exhibit deficits in interneuron migration, understanding the function of Arx in interneuron migration will prove crucial to understanding the pathology underlying interneuronopathies. Yet, downstream transcriptional targets of Arx, to date, remain unidentified.
Publication Title
Identification of Arx transcriptional targets in the developing basal forebrain.
Sample Metadata Fields
No sample metadata fields
View Samples- Danio rerio
- 1 Downloadable Sample
Description
Fluorescent-labeled zebrafish RAS-induced embryonal rhabdomyosarcoma (ERMS) were created to facilitate in vivo imaging of tumor-propagating cells, regional tumor heterogeneity, and dynamic cell movements in diverse cellular compartments. Using this strategy, we have identified a molecularly distinct ERMS cell subpopulation that expresses high levels of myf5 and is enriched for ERMS-propagating potential when compared with other tumor-derived cells. Embryonal rhabdomyosarcoma (ERMS) is an aggressive pediatric sarcoma of muscle. Here, we show that tumor-propagating potential is confined to myf5+ERMS cells and can be visualized in live, fluorescent transgenic zebrafish. During early tumor growth, myf5+ERMS cells reside within an expanded satellite cell compartment, but by late stage ERMS, myf5+cells are dynamically reorganized into distinct regions separated from differentiated tumor cells. Human ERMS also contain distinct areas of differentiated and undifferentiated cells. Time-lapse imaging revealed that myf5+ERMS cells populate newly formed tumor only after seeding by highly migratory myogenin+ ERMS cells. This finding helps explain the clinical observation that Myogenin positivity correlates with poor clinical outcome in human ERMS and suggests that differentiated tumor cells play critical roles in metastasis. One-cell stage myf5-GFP/mylz2-mCherry fluorescent transgenic zebrafish were injected with rag2-kRAS12D. A subset of animals developed ERMS. Tumor cells were transplanted into syngeneic recipient animals that lacked fluorescent reporter expression. ERMS cell subfractions were isolated from transplant animals and purified cell populations obtained following two rounds of FACS. Sorted cells were 1) analyzed by microarray/RT-PCR and 2) transplanted at limiting dilution into syngeneic animals. These experiments confirm that zebrafish ERMS contain molecularly distinct cell subfractions that express high levels of myf5-GFP and exhibit difference in gene expression when compared to other ERMS cell subtypes. All four fluorescent-labeled cell populations were analyzed (n=2 tumors total).
Publication Title
In vivo imaging of tumor-propagating cells, regional tumor heterogeneity, and dynamic cell movements in embryonal rhabdomyosarcoma.
Sample Metadata Fields
Specimen part, Disease, Disease stage, Subject
View Samples