This SuperSeries is composed of the SubSeries listed below.
Human fetal hemoglobin expression is regulated by the developmental stage-specific repressor BCL11A.
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View SamplesDifferences in the amount of fetal hemoglobin (HbF) that persists into adulthood affect the severity of sickle cell disease and the beta-thalassemia syndromes. Genetic association studies have identified sequence variants in the gene BCL11A that influence HbF levels. Here we examine BCL11A as a potential regulator of HbF expression. The high HbF BCL11A genotype is associated with reduced BCL11A expression. Moreover, abundant expression of full-length forms of BCL11A is developmentally restricted to adult erythroid cells. Down-regulation of BCL11A expression in primary adult erythroid cells leads to robust HbF expression. Consistent with a direct role of BCL11A in globin gene regulation, we find that BCL11A occupies several discrete sites in the beta-globin gene cluster. BCL11A emerges as a therapeutic target for reactivation of HbF in beta-hemoglobin disorders.
Human fetal hemoglobin expression is regulated by the developmental stage-specific repressor BCL11A.
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View SamplesExpression data from mice exposed to intermittent hypoxia and mice reared for 12 months. We used microarrays to analyze the transcriptome of hippocampus from mice exposed to intermittent hypoxia or aged mice.
Treatment of intermittent hypoxia increases phosphorylated tau in the hippocampus via biological processes common to aging.
Specimen part, Treatment
View SamplesExercise training improves whole body glucose homeostasis through effects largely attributed to adaptations in skeletal muscle; however, training also affects other tissues including adipose tissue. To determine if exercise-induced adaptations to adipose tissue contribute to training-induced improvements in glucose homeostasis, subcutaneous white adipose tissue (scWAT) from trained or sedentary donor mice was transplanted into the visceral cavity of sedentary recipients. Remarkably, nine days post-transplantation, mice receiving trained scWAT had improved glucose tolerance and enhanced insulin sensitivity compared to mice transplanted with sedentary scWAT or sham-treated mice. Mice transplanted with trained scWAT had increased insulin-stimulated glucose uptake in tibialis anterior and soleus muscles and brown adipose tissue, suggesting that the transplanted scWAT exerted endocrine effects. Furthermore, the deleterious effects of high-fat feeding on glucose tolerance and insulin sensitivity were completely reversed if high-fat fed recipient mice were transplanted with trained scWAT. In additional experiments, voluntary exercise training by wheel running for only 11 days resulted in profound changes in scWAT including increased expression of 1550 genes involved in numerous cellular functions, including metabolism. Exercise training causes adaptations to scWAT that elicit metabolic improvements in other tissues, demonstrating a previously unrecognized role for adipose tissue in the beneficial effects of exercise on systemic glucose homeostasis.
A novel role for subcutaneous adipose tissue in exercise-induced improvements in glucose homeostasis.
Sex, Age, Specimen part
View SamplesD-3-Phosphoglycerate dehydrogenase (Phgdh; EC 1.1.1.95) is a necessary enzyme for de novo L-serine biosynthesis via the phosphorylated pathway. We demonstrated previously that Phgdh is expressed exclusively by neuroepithelium and radial glia in developing mouse brain and later mainly by astrocytes. Mutations in the human PHGDH gene cause serine deficiency disorders (SDD) associated with severe neurological symptoms such as congenital microcephaly, psychomotor retardation, and intractable seizures. We recently demonstrated that genetically engineered mice, in which the gene for Phgdh has been disrupted, have significantly decreased levels of serine and glycine, and exhibit malformation of brain such as microcephaly. The Phgdh null (KO) embryos exhibit lethal phenotype after gestational day 14, indicating that the phosphorylated pathway is essential for embryogenesis, especially for brain development. It is worth noting that the Phgdh knockout (KO) embryos primarily displayed microcephaly, which is the most conspicuous phenotype of patients with SDD. Thus, Phgdh KO mice are a useful animal model for studying the effect of diminished L-serine levels on development of the central nervous system and other organs. To better understand the mechanism underlying the molecular pathogenesis of SDD, we sought to examine whether gene expression is altered in the Phgdh KO mouse model. We identify genes that have altered expression in the head of the Phgdh KO embryos using the GeneChip array. Some of the genes identified by this method belong in functional categories that are relevant to the biochemical and morphological aberrations of the Phgdh deletion.
Inactivation of the 3-phosphoglycerate dehydrogenase gene in mice: changes in gene expression and associated regulatory networks resulting from serine deficiency.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Activation of the aryl hydrocarbon receptor dampens the severity of inflammatory skin conditions.
Sex, Age, Specimen part, Treatment, Subject
View SamplesEnvironmental stimuli are known to contribute to psoriasis pathogenesis and that of other autoimmune diseases, but the mechanism is unknown. Here we show that the aryl hydrocarbon receptor (AhR), a transcription factor that senses environmental stimuli, modulates pathology in psoriasis. AhR-activating ligands reduced inflammation in the lesional skin of psoriasis patients, whereas AhR antagonists upregulated inflammation. Similarly, AhR signaling via the endogenous FICZ ligand reduced the inflammatory response in the imiquimod-induced model of psoriasis and AhR deficient mice exhibited a substantial exacerbation of the disease, compared to AhR sufficient controls. Non-haematopoietic cells, in particular keratinocytes, were responsible for this hyper-inflammatory response, which involved increased reactivity to IL-1beta and upregulation of AP-1 family members of transcription factors. Thus, our data suggest a critical role for AhR in the regulation of inflammatory responses and open the possibility for novel therapeutic strategies in chronic inflammatory disorders.
Activation of the aryl hydrocarbon receptor dampens the severity of inflammatory skin conditions.
Specimen part
View SamplesSTAT3 is a pleiotropic transcription factor with important functions in cytokine signalling in a variety of tissues. However, the role of STAT3 in the intestinal epithelium is not well understood. Here we demonstrate that development of colonic inflammation is associated with the induction of STAT3 activity in intestinal epithelial cells (IEC). Studies in genetically engineered mice showed that epithelial STAT3 activation in DSS colitis is dependent on IL-22 rather than IL-6. IL-22 was secreted by colonic CD11c+ cells in response to Toll-like receptor stimulation. Conditional knockout mice with an IEC specific deletion of STAT3 activity were highly susceptible to experimental colitis, indicating that epithelial STAT3 regulates gut homeostasis. STAT3IEC-KO mice, upon induction of colitis, showed a striking defect of epithelial restitution. Gene chip analysis indicated that STAT3 regulates the cellular stress response, apoptosis and pathways associated with wound healing in IEC. Consistently, both IL-22 and epithelial STAT3 were found to be important in wound-healing experiments in vivo. In summary, our data suggest that intestinal epithelial STAT3 activation regulates immune homeostasis in the gut by promoting IL-22-dependent mucosal wound healing.
STAT3 links IL-22 signaling in intestinal epithelial cells to mucosal wound healing.
Specimen part
View SamplesInterleukin 2 (IL-2), a cytokine linked to human autoimmune diseases, limits IL-17 production. We show that deletion of Stat3 in T cells abrogates IL-17 production and attenuates autoimmunity associated with IL-2 deficiency. While STAT3 induces IL-17 and RORt and inhibits Foxp3, IL-2 inhibited IL-17 independently of Foxp3 and RORt. We found that STAT3 and STAT5 bound to multiple common sites across the Il17 genetic locus. The induction of STAT5 binding by IL-2 was associated with a reduction in STAT3 binding at these sites and the inhibition of associated active epigenetic marks. Titrating the relative activation of STAT3 and STAT5 modulated TH17 cell specification. Thus, the balance rather than the absolute magnitude of these signals determines the propensity of cells to make a key inflammatory cytokine.
Opposing regulation of the locus encoding IL-17 through direct, reciprocal actions of STAT3 and STAT5.
Specimen part
View SamplesEpigenetic gene regulation in various oncogenic pathways is currently an important focus of cancer research. The PI3K pathway plays a pivotal role in hepatocellular carcinoma, but the significance of histone modification in the PI3K pathway-dependent hepatotumorigenesis remains unknown.
Impact of histone demethylase KDM3A-dependent AP-1 transactivity on hepatotumorigenesis induced by PI3K activation.
Specimen part
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