The intestine is an organ with exceptionally high rate of cell turnover and perturbations in this process can lead to disease such as cancer or intestinal atrophy. Nutrition is a key factor regulating the intestinal cell turnover and has a profound impact on intestinal volume and cellular architecture. However, how the intestinal equilibrium is maintained in fluctuating dietary conditions is insufficiently understood. By utilizing the Drosophila midgut as a model, we reveal a novel nutrient sensing mechanism coupling stem cell metabolism with stem cell extrinsic growth signal. Our results show that intestinal stem cells (ISCs) employ the hexosamine biosynthesis pathway (HBP) to monitor nutritional status and energy metabolism. Elevated activity of the HBP promotes Warburg effect-like metabolic reprogramming, which is required for the reactivation of ISCs from calorie restriction-induced quiescence. Furthermore, the HBP activity is an essential facilitator for insulin signaling-induced intestinal growth. In conclusion, intestinal stem cell intrinsic nutrient sensing regulates metabolic pathway activities, and defines the stem cell responsiveness to niche-derived growth signals. Overall design: Intestinal mRNA profiles of 7 days old mated females of UAS-mCD8::GFP, hsFLP; tub-GAL4/+; FRT82B tub-GAL80/FRT82B genotype kept in calorie-restriction +/- 0.1M D-acetylglucosamine for 24h.
Stem Cell Intrinsic Hexosamine Metabolism Regulates Intestinal Adaptation to Nutrient Content.
Sex, Specimen part, Treatment, SubjectView Samples
Characterization of the underlying genetic defects in patients with a rare and peculiar phenotype is challenging. Here we have utilized whole genome expression profiling, and identified a homozygous germline mutation in the DDB2 gene in a patient with several facial tumors. The feasibility of using blood derived RNA, diminishing costs of the technology, and the limited number of samples needed provide this approach a powerful new tool that may substantially aid in such gene identification efforts.
Blood-derived gene-expression profiling in unravelling susceptibility to recessive disease.
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Acquisition of the lower jaw (mandible) was evolutionarily important for jawed vertebrates. In humans, syndromic craniofacial malformations often accompany jaw anomalies. Hand2 is involved in coordinating the developmental network of mandibles and the oral apparatus through Hand2-downstream genes and is therefore a major determinant of jaw identity.
Specification of jaw identity by the Hand2 transcription factor.
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Both environmental and genetic factors play important roles in the development of the metabolic syndrome. To elucidate how these factors interact under normal conditions, C57Bl/6 (B6) and 129S6/SvEvTac (129) mice were placed on a low-fat or high-fat diet. Liver samples were extracted and hybridized to Affymetrix Genome U74 (version 2) arrays.
Effects of diet and genetic background on sterol regulatory element-binding protein-1c, stearoyl-CoA desaturase 1, and the development of the metabolic syndrome.
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SKBR3 cells expressing NDRG1 shRNA1 or vector control were harvested by trypsinization and total RNA was extracted. Silencing NDRG1 reduces cell proliferation rates, causing lipid metabolism dysfunction including increased fatty acid incorporation into neutral lipids and lipid droplets.
NDRG1 regulates neutral lipid metabolism in breast cancer cells.
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In mouse, spermatogonial stem/progenitor cells are the progenitor cell which develop to mature sperms through a series of mitotic and meiotic divisions and differentiation. Gfra1 is an established surface marker for mouse spermatogonial stem/progenitor cells. In this study, we used a transcriptomic approach to investigate the effect of aging on Gfra1-positive and -negative populations of mouse male germ cells.
Age affects gene expression in mouse spermatogonial stem/progenitor cells.
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Sucrose is a major carbon source for industrial bioethanol production by Saccharomyces cerevisiae. In yeasts, two modes of sucrose metabolism occur: (i) extracellular hydrolysis by invertase, followed by uptake and metabolism of glucose and fructose, and (ii) uptake via sucrose-H+ symport followed by intracellular hydrolysis and metabolism. Although alternative start codons in the SUC2 gene enable synthesis of extracellular and intracellular invertase isoforms, sucrose hydrolysis in S. cerevisiae predominantly occurs extracellularly. In anaerobic cultures, intracellular hydrolysis theoretically enables a 9 % higher ethanol yield than extracellular hydrolysis, due to energy costs of sucrose-proton symport. This prediction was tested by engineering the promoter and 5 coding sequences of SUC2, resulting in relocation of invertase to the cytosol. In anaerobic sucrose-limited chemostats, this iSUC2-strain showed an only 4% increased ethanol yield and high residual sucrose concentrations indicated suboptimal sucrose-transport kinetics. To improve sucrose-uptake affinity, it was subjected to 95 generations of anaerobic, sucrose-limited chemostat cultivation, resulting in a 20-fold decrease of residual sucrose concentrations and a 10-fold increase of the sucrose-transport capacity. A single-cell isolate showed an 11 % higher ethanol yield on sucrose in chemostat and batch cultures than an isogenic SUC2 reference strain, while transcriptome analysis revealed elevated expression of AGT1, encoding a disaccharide-proton symporter, and other maltose-related genes. Deletion of AGT1, which had been duplicated during laboratory evolution, restored the growth characteristics of the unevolved iSUC2 strain. This study demonstrates that engineering the topology of sucrose metabolism is an attractive strategy to improve ethanol yields in industrial processes.
Increasing free-energy (ATP) conservation in maltose-grown Saccharomyces cerevisiae by expression of a heterologous maltose phosphorylase.
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17b-Estradiol added to MEL cells expressing Gata1-ER or PU.1-ER transgenes to stimulate either erythropoietic Gata-1 dependent or myeloid PU.1 dependent gene espression in different time points
PU.1 activation relieves GATA-1-mediated repression of Cebpa and Cbfb during leukemia differentiation.
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In contrast to urodele amphibians and teleost fish, mammals lack the regenerative responses to replace large body parts. Amphibian and fish regeneration uses dedifferentiation, i.e. reversal of differentiated state, as a means to produce progenitor cells to eventually replace damaged tissues. Therefore, activation of dedifferentiation response in mammalian tissues holds an immense promise for human regenerative medicine. msx2 expression has been shown to peak at the early time points of amphibian limb regeneration. Despite this temporal importance in the heterogenous regenerating limb tissues, the potential role of msx2 in dedifferentiation was previously not addressed in salamander or mammalian muscle cells. In order to test this, we ectopically overexpressed msx2 in mammalian myotubes and profiled their transcriptomes using next generation sequencing. We identified 4964 up-regulated and 4464 down-regulated transcripts in myotubes compared to myoblasts (uninduced GFP control cells; = 1.5 fold; FDR corrected p-values < 0.01). Upon ectopic msx2 expression in myotubes, 923 transcripts were downregulated, whereas 1283 transcripts were upregulated. Based on msx2's potential role in dedifferentiation, we reasoned that the transcripts, which are normally upregulated in myotubes in comparison to myoblasts, should go down upon msx2-expression. In accord with this idea, 575 myotube-enriched transcripts were downregulated after one day of ectopic msx2 expression. Similarly, 331 myoblast-enriched transcripts were upregulated upon msx2 expression. Overall design: To extensively analyze transcriptome-wide changes upon ectopic msx2 expression in mammalian myotubes, we performed next generation RNA-sequencing (RNA-seq) on uninduced and induced isolated myotubes that have msx2 and GFP or GFP alone transgenes. As a reference for the undifferentiated state, we also sequenced the transcriptomes of uninduced myoblast cultures of these two transgenic constructs. Deep sequencing was performed using Illumina HiSeq.
Ectopic expression of Msx2 in mammalian myotubes recapitulates aspects of amphibian muscle dedifferentiation.
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Infliximab (IFX) has been reported as the further therapy in intravenous immunoglobulin G (IVIG)-resistant Kawasaki disease (KD) patients. IFX is a monoclonal antibody that blocks the pro-inflammatory cytokine tumor necrosis factor (TNF)-, but how IFX affect KD vasculitis is unknown. We investigated expression profiling of whole blood cells to elucidate the molecular mechanisms of the effectiveness of IFX therapy and to find characteristic biomarker and an important target in refractory KD. Methods: Refractory KD patients who failed to respond to repeated intravenous immunoglobulin G (IVIG) infusions had received a single infusion of IFX as third therapy. To validate specifically transcripts abundance for IFX therapy, we detected the altered transcripts expression and signaling pathways of whole blood mRNA in these IFX-responsive patients (n=8) using Affymetrix array, comparing initial IVIG-responsive patients (n=6).Results: A total of 1,388 transcripts abundance were significantly altered before and after IFX treatment. These transcripts abundance in IFX had Nucleotide-binding oligomerization domain pathway that play a role in activation of NFB and IL-1 signaling pathway outside the field of TNF- signaling pathway. Fifty transcripts including Peptidase inhibitor-3 (PI3), Matrix metalloproteinase-8 (MMP8), Chemokine (C-C motif) receptor-2 (CCR2) and Pentraxin-3 (PTX3) were significantly down-regulated in IFX. Conclusion: We demonstrated that the inhibition of TNF- by IFX have affected various molecular mechanism materially for IVIG-resistant KD patients.
Transcriptional regulation by infliximab therapy in Kawasaki disease patients with immunoglobulin resistance.
Specimen part, Disease, Disease stage, Treatment, SubjectView Samples