Neurons in the arcuate nucleus (ARC) sense the fed/fasted state and regulate hunger. ARCAgRP neurons release GABA, NPY and the melanocortin-4 receptor (MC4R) antagonist, AgRP, and are activated by fasting1-4. When stimulated, they rapidly and potently drive hunger5,6. ARCPOMC neurons, in contrast, release the MC4R agonist, a-MSH, and are viewed as the counterpoint to ARCAgRP neurons. They are regulated in an opposite fashion and their activity leads to decreased hunger2,4,7. Together, ARCAgRP and ARCPOMC neurons constitute the ARC feeding center. Against this, however, is the finding that ARCPOMC neurons, unlike ARCAgRP neurons, fail to affect food intake over the timescale of minutes to hours following opto- or chemogenetic stimulation5,8. This suggests a rapidly acting component of the ARC satiety pathway is missing. Here, we show that excitatory ARC neurons identified by expression of vesicular glutamate transporter 2 (VGLUT2) and the oxytocin receptor, unlike ARCPOMC neurons, rapidly cause satiety when chemo- or optogenetically manipulated. These glutamatergic ARC projections synaptically converge with GABAergic ARCAgRP projections on MC4R-expressing neurons in the paraventricular hypothalamus (PVHMC4R neurons), which are known to mediate satiety9. ARCPOMC neurons also send dense projections to the PVH. Importantly, the a-MSH they release post-synaptically potentiates glutamatergic synaptic activity onto PVHMC4R neurons – including that emanating from ARCVglut2 neurons. This suggests a means by which a-MSH can bring about satiety – via postsynaptic potentiation of this novel ARCVglut2 to PVHMC4R satiety circuit. Thus, while fast (GABA and NPY) and slow (AgRP) ARC hunger signals are delivered together by ARCAgRP neurons10,11, the temporally analogous satiety signals from the ARC, glutamate and a-MSH, are delivered separately by two parallel, interacting projections (from ARCVGLUT2 and ARCPOMC neurons). Discovery of this rapidly acting excitatory ARC ? PVH satiety circuit, and its regulation by a-MSH, provides new insight into regulation of hunger/satiety. Overall design: 23 samples representing single neurons dissociated from the arcuate hypothalamus of two young adult male vGLUT2-IRES-Cre mice
A rapidly acting glutamatergic ARC→PVH satiety circuit postsynaptically regulated by α-MSH.
Specimen part, Cell line, Subject
View SamplesDuring gastrulation, epiblast cells are pluripotent and their fate is thought to be constrained principally by their position. Cell fate is progressively restricted by localised signalling cues from areas including the primitive streak (PS). However, it is unknown whether this restriction accompanies, at the single cell level, a reduction in potency. Investigation of these early transition events in vitro is possible via the use of Epiblast Stem Cells (EpiSCs), self-renewing pluripotent cell lines equivalent to the postimplantation epiblast. Strikingly, EpiSCs express various early lineage-specific markers in self-renewing conditions. However, it is unknown whether cells that express these markers are pluripotent, spontaneously differentiated, or biased towards specific lineages. Here we show that EpiSC are inherently heterogeneous and contain two major and mutually exclusive subpopulations with PS and neural characteristics respectively. Using differentiation assays and embryo grafting we demonstrate that PS-like EpiSCs are biased towards mesoderm and endoderm differentiation but they still retain their pluripotent character. The acquisition of a PS character by undifferentiated EpiSC is mediated by paracrine Wnt signalling. Elevation of Wnt activity promotes further restriction into PS-associated cell fates which occurs via the generation of distinct clonal mesendodermal and neuromesodermal precursors. Collectively, our data suggest that primed pluripotency encompasses a range of reversible lineage-biased states reflecting the birth of pioneer lineage precursors from a pool of uncommitted EpiSCs similar to the earliest cell fate restriction events taking place in the gastrula-stage epiblast.
Distinct Wnt-driven primitive streak-like populations reflect in vivo lineage precursors.
Sex, Specimen part
View SamplesAlefacept treatment is highly effective in a select group patients with moderate-to-severe psoriasis, and is an ideal candidate to develop systems to predict who will respond to therapy. A clinical trial of 22 patients with moderate to severe psoriasis treated with alefacept (7.5mg weekly i.v. x12 weeks) was conducted in 2002-2003, as a mechanism of action study. Patients were classified as responders or non-responders to alefacept based on histological criteria. Microarray data from PBMCs of 16 of these patients was analyzed to generate a treatment response classifier. We used a discriminant analysis method that performs sample classification from gene expression data, via nearest shrunken centroid method''. A disease response classifier using 23 genes was created to accurately predict response to alefacept (12.3% error rate in favour of responders). This preliminary study may provide a useful tool to predict response of psoriatic patients with alefacept.
Personalized medicine in psoriasis: developing a genomic classifier to predict histological response to Alefacept.
Sex, Age, Specimen part, Subject
View SamplesPro-opiomelanocortin (POMC)- and agouti-related peptide (AgRP)-expressing neurons of the arcuate nucleus of the hypothalamus (ARC) are oppositely regulated by caloric depletion and coordinately stimulate and inhibit homeostatic satiety, respectively. This bimodality is principally underscored by the antagonistic actions of these ligands at downstream melanocortin-4 receptors (MC4R) in the paraventricular nucleus of the hypothalamus (PVH). Although this population is critical to energy balance, the underlying neural circuitry remains unknown. Using mice expressing Cre recombinase in MC4R neurons, we demonstrate bidirectional control of feeding following real-time activation and inhibition of PVH(MC4R) neurons and further identify these cells as a functional exponent of ARC(AgRP) neuron-driven hunger. Moreover, we reveal this function to be mediated by a PVH(MC4R)?lateral parabrachial nucleus (LPBN) pathway. Activation of this circuit encodes positive valence, but only in calorically depleted mice. Thus, the satiating and appetitive nature of PVH(MC4R)?LPBN neurons supports the principles of drive reduction and highlights this circuit as a promising target for antiobesity drug development. Overall design: Single-neuron mRNA-seq was performed on fluorescently-labeled or -unlabeled cells that were manually isolated from dissociated adult mouse paraventricular and arcuate hypothalamus: Mc4r-2a-Cre::L10-GFP+ or Mc4r-2a-Cre::AAV-XFP+ or Mc4r-2a-Cre::AAV-XFP-negative PVH neurons; Agrp-IRES-Cre::L10-GFP+ ARC neurons; Pomc-hrGFP+ ARC neurons; and vGLUT2-IRES-Cre::AAV-XFP+ ARC neurons Note: Raw files unavailable for samples GSM2413312 GSM2413313 GSM2413314 GSM2413346 GSM2413347
A neural basis for melanocortin-4 receptor-regulated appetite.
Sex, Specimen part, Cell line, Subject
View SamplesPGC1beta is a transcriptional coactivator that potently stimulates mitochondrial biogenesis and respiration of cells. Here, we have generated mice lacking exons 3 to 4 of the Pgc1beta gene (PGC1beta E3,4-/E3,4- mice). These mice express a mutant protein that has reduced coactivation activity on a subset of transcription factors, including ERRalpha, a major target of PGC1beta in the induction of mitochondrial gene expression. The mutant mice have reduced expression of OXPHOS genes and mitochondrial dysfunction in liver and skeletal muscle as well as elevated liver triglycerides. Euglycemic-hyperinsulinemic clamp and insulin signaling studies show that PGC1beta mutant mice have normal skeletal muscle response to insulin, but have hepatic insulin resistance. These results demonstrate that PGC1beta is required for normal expression of OXPHOS genes and mitochondrial function in liver and skeletal muscle. Importantly, these abnormalities do not cause insulin resistance in skeletal muscle but cause substantially reduced insulin action in the liver.
Hypomorphic mutation of PGC-1beta causes mitochondrial dysfunction and liver insulin resistance.
No sample metadata fields
View SamplesThe success of TNF inhibitors for treatment of psoriasis and other inflammatory diseases was previously attributed to blockade of innate immunity. In a clinical trial using etanercept TNF blocking agent to treat psoriasis vulgaris, we used affymetrix gene arrays to analyze broad gene profiles in lesional skin at multiple timepoints during drug treatment (baseline, and weeks 1, 2, 4 and 12) compared to non-lesional skin. This analysis created a temporal model of TNF-dependent gene regulation that informs molecular mechanisms of TNF-mediated inflammation. We identified four gene clusters that were differentially down-modulated during etanercept treatment: the cluster down-regulated most rapidly contained mostly dendritic cell activation genes. Culturing human keratinocytes with TNF, IFNg and IL-17 generated a list of keratinocyte genes regulated by each cytokine. The IL-17 pathway genes were strongly down-modulated early, whereas IFNg pathway genes were not down-modulated until final disease resolution at week 12. Finally, we show that TNF blockade rapidly inhibits IL-12/IL-23 p40 subunit expression, and that p40 neutralization inhibits psoriatic dermal migr-mediated Th17 polarization. We hypothesize that etanercept inhibits myeloid dendritic cell production of IL-23, a Th17 survival cytokine, resulting in rapid downregulation of IL-17 pathway genes. This data links effects of TNF blockade on the innate immune system with the adaptive immune system.
Effective treatment of psoriasis with etanercept is linked to suppression of IL-17 signaling, not immediate response TNF genes.
Subject, Time
View SamplesMild vs. severe psoriasis vulgaris is often distinguished by the Psoriasis Area and Severity Index. It is widely assumed that severe psoriasis involves higher levels of skin inflammation, but comparative molecular profiles of mild vs. severe disease have not been previously performed. In this study, we used gene arrays to phenotype North American patients with mild psoriasis vs. severe psoriasis.
The Spectrum of Mild to Severe Psoriasis Vulgaris Is Defined by a Common Activation of IL-17 Pathway Genes, but with Key Differences in Immune Regulatory Genes.
Disease, Disease stage
View SamplesIn this study, we sought to determine how IL-17 and TNF influence normal human melanocytes, either alone, or with both cytokines together. We reveal a dichotomous effect of IL-17 and TNF, which not only elicit essential mitogenic cytokines but also suppress melanogenesis by down-regulating genes of melanogenesis pathway
IL-17 and TNF synergistically modulate cytokine expression while suppressing melanogenesis: potential relevance to psoriasis.
Specimen part, Treatment, Time
View SamplesPsoriasis is a chronic, debilitating, immune-mediated inflammatory skin disease. As IFN- is involved in many cellular processes, including activation of T cells and dendritic cells (DCs), antigen processing and presentation, cell adhesion and trafficking, and cytokine and chemokine production, IFN--producing Th1 cells were proposed to be integral to the pathogenesis of psoriasis. Recently, IFN- was shown to enhance IL-23 and IL-1 production by DCs and subsequently induce Th17 cells, important contributors to the inflammatory cascade in psoriasis lesions. To determine if IFN- indeed induces the pathways leading to the development of psoriasis lesions, a single intradermal injection of IFN- was administered to an area of clinically normal, non-lesional skin of psoriasis patients and biopsies were collected 24 hours later. Although there were no visible changes in the skin, IFN- induced molecular and histological features characteristic of psoriasis lesions. IFN- increased a number of differentially expressed genes in the skin, including many chemokines concomitant with an influx of T cells and inflammatory DCs. Furthermore, inflammatory DC products TNF, iNOS, IL-23, and TRAIL were present in IFN--treated skin. Thus, IFN-, which is significantly elevated in non-lesional skin compared to healthy skin, appears to be a key pathogenic cytokine that can induce the inflammatory cascade in psoriasis.
A single intradermal injection of IFN-γ induces an inflammatory state in both non-lesional psoriatic and healthy skin.
Disease, Disease stage
View SamplesTo understand the mechanism of disease progression in psoriasis, we defined Asian small plaque psoriasis (small psoriasis) and Asian intermediate plaque psoriasis (intermediate psoriasis) as psoriasis subtypes with limited disease progression, and compared their cellular and molecular signatures with the classic subtype of Western large plaque psoriasis (large psoriasis; GSE30999).
Molecular Phenotyping Small (Asian) versus Large (Western) Plaque Psoriasis Shows Common Activation of IL-17 Pathway Genes but Different Regulatory Gene Sets.
Specimen part, Disease, Disease stage, Treatment, Subject
View Samples