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GSE36151
Saccharomyces cerevisiae
18 Downloadable Samples
Affymetrix Yeast Genome 2.0 Array (yeast2)
Description
When grown on solid substrates, different microorganisms often form colonies with very specific morphologies. Whereas the pioneers of microbiology often used colony morphology to discriminate between species and strains, the phenomenon has not received much recent attention. In this study, we use a genome-wide assay in the model yeast Saccharomyces cerevisiae to identify all genes that affect colony morphology. We show that several major signaling cascades, including the MAPK, TORC, SNF1 and RIM101 pathways play a role, indicating that morphological changes are a reaction to changing environments. Other genes that affect colony morphology are involved in protein sorting and epigenetic regulation. Interestingly, the screen reveals only few genes that are likely to play a direct role in establishing colony morphology, one notable exception being FLO11, a gene encoding a cell-surface adhesin that has already been implicated in colony morphology, biofilm formation, and invasive and pseudohyphal growth. Using a series of modified promoters to tune FLO11 expression, we confirm the central role of Flo11 and show that differences in FLO11 expression result in distinct colony morphologies. Together, our results provide a first comprehensive looks at the complex genetic network that underlies the diversity in the morphologies of yeast colonies.
Publication Title
Identification of a complex genetic network underlying Saccharomyces cerevisiae colony morphology.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 23 Downloadable Samples
- Affymetrix Mouse Gene 1.1 ST Array (mogene11st)
Description
Red meat consumption is associated with an increased colon cancer risk. Heme, present in red meat, injures the colon surface epithelium by luminal cytotoxicity and reactive oxygen species. This surface injury is overcompensated by hyperproliferation and hyperplasia of crypt cells. Transcriptome analysis of mucosa of heme-fed mice showed, besides stress- and proliferation-related genes, many upregulated lipid metabolism-related PPAR target genes. The aim of this study was to investigate the role of PPAR in heme-induced hyperproliferation and hyperplasia. Male PPAR KO and WT mice received a purified diet with or without heme. As PPAR is proposed to protect against oxidative stress and lipid peroxidation, we hypothesized that the absence of PPAR leads to more surface injury and crypt hyperproliferation in the colon upon heme-feeding. Heme induced luminal cytotoxicity and lipid peroxidation and colonic hyperproliferation and hyperplasia to the same extent in WT and KO mice. Transcriptome analysis of colonic mucosa confirmed similar heme-induced hyperproliferation in WT and KO mice. Stainings for alkaline phosphatase activity and expression levels of Vanin-1 and Nrf2-targets indicated a compromised antioxidant defense in heme-fed KO mice. Our results suggest that the protective role of PPAR in antioxidant defense involves the Nrf2-inhibitor Fosl1, which is upregulated by heme in PPAR KO mice. We conclude that PPAR plays a protective role in colon against oxidative stress, but PPAR does not mediate heme-induced hyperproliferation. This implies that oxidative stress of surface cells is not the main determinant of heme-induced hyperproliferation and hyperplasia.
Publication Title
Dietary heme-mediated PPARα activation does not affect the heme-induced epithelial hyperproliferation and hyperplasia in mouse colon.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 36 Downloadable Samples
Illumina HiSeq 2500
Description
By conditionally deleting BRD4 at various stages of thymic differentiation, we have established that BRD4 deficiency selectively affects a unique developmental subpopulation of thymocytes. Overall design: We examined by RNA-seq the effect on gene expression of BRD4 deletion in ex vivo DN, ISP, DP, CD4 and CD8 thymocyte subpopulations. The analysis was also performed on WT or BRD4 deleted ISP and DP thymocytes cultured for 16 hours at 37oC In this analysis, the conditional deletion of BRD4 (cKO) is achieved using the LCK-cre Transgene.
Publication Title
Immature CD8 Single-Positive Thymocytes Are a Molecularly Distinct Subpopulation, Selectively Dependent on BRD4 for Their Differentiation.
Sample Metadata Fields
Specimen part, Treatment, Subject
View Samples- Mus musculus
- 19 Downloadable Samples
Affymetrix Mouse Gene 1.0 ST Array (mogene10st), Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sample Metadata Fields
Sex, Age, Specimen part, Treatment
View Samples- Mus musculus
- 16 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
The risk for colon cancer is associated with nutrition, especially high fat and low calcium diets high in red meat. Red meat contains the iron porphyrin pigment heme, which induces cytotoxicity of the colon contents and epithelial hyperproliferation. Using a mouse model, we showed that heme caused damage to the colonic surface epithelium and induced compensatory hyperproliferation. Expression levels of heme- and stress-related genes show that heme affects surface cells and not directly crypt cells. Therefore, injured surface cells should signal to crypt TA cells to induce compensatory hyperproliferation. Surface-specific downregulated inhibitors of proliferation were Wnt inhibitory factor 1, Indian Hedgehog, Bone morphogenic protein 2 and possibly Interleukin-15. Heme also upregulated Amphiregulin, Epiregulin and Cyclooxygenase-2 mRNA in the surface cells, however, their protein/metabolite levels were not increased as heme induced surface-specific translation repression by increasing 4E-BP1. Therefore, we conclude that heme induced colonic hyperproliferation and hyperplasia by repressing feedback inhibition of proliferation.
Publication Title
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sample Metadata Fields
Sex, Age, Specimen part, Treatment
View Samples- Mus musculus
- 3 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302), Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
The risk for colon cancer is associated with nutrition, especially with diets high in red meat. Red meat contains the iron porphyrin pigment heme, which induces cytotoxicity of the colon contents and epithelial hyperproliferation. Using a mouse model, we showed that heme caused damage to the colonic surface epithelium and induced compensatory hyperproliferation. Expression levels of heme- and stress-related genes show that heme affects surface cells and not directly crypt cells. Therefore, injured surface cells should signal to crypt TA cells to induce compensatory hyperproliferation. Surface-specific downregulated inhibitors of proliferation were Wnt inhibitory factor 1, Indian Hedgehog, Bone morphogenic protein 2 and possibly Interleukin-15. Heme also upregulated Amphiregulin, Epiregulin and Cyclooxygenase-2 mRNA in the surface cells, however, their protein/metabolite levels were not increased as heme induced surface-specific translation repression by increasing 4E-BP1. Therefore, we conclude that heme induced colonic hyperproliferation and hyperplasia by repressing feedback inhibition of proliferation.
Publication Title
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sample Metadata Fields
Sex, Age, Specimen part, Treatment
View Samples- Homo sapiens
- 23 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Probiotic bacteria, specific representatives of bacterial species that are a common part of the human microbiota, are proposed to deliver health benefits to the consumer by modulation of intestinal function via largely unknown molecular mechanisms. To explore in vivo mucosal responses of healthy adults to probiotics, we obtained transcriptomes in an intervention study following a double-blind placebo-controlled cross-over design. In the mucosa of the proximal small intestine of healthy volunteers, probiotic strains from the species Lactobacillus acidophilus, L. casei and L. rhamnosus each induced differential gene regulatory networks and pathways in the human mucosa. Comprehensive analyses revealed that these transcriptional networks regulate major basal mucosal processes, and uncovered remarkable similarity to response profiles obtained for specific bioactive molecules and drugs. This study elucidates how intestinal mucosa of healthy humans perceive different probiotics and provides avenues for rationally designed tests of clinical applications.
Publication Title
Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 18 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Obesity and insulin resistance are two major risk factors underlying the metabolic syndrome. To gain more insight in the role of the small intestine in the etiology of these metabolic disorders, a microarray study was performed on small intestines (SI) of C57BL/6J mice that were fed a high fat diet mimicking the fatty acid composition of a Western-style human diet. The mice became obese and developed dietary fat-induced glucose intolerance. For gene expression profiling, the small intestines were subdivided in three equal parts along the longitudinal axis. The most pronounced effects of dietary fat were detected in part 2 of the small intestine. The biological processes that were most extensively modulated on a high fat diet were related to lipid metabolism, especially - and -fatty acid oxidation seemed to play an important role, cell cycle and inflammation/immune response. An additional secretome analysis revealed differentially expressed secreted proteins, such as Il18, Ffgf15, Mif, Igfbp3 and Angptl4, which might provoke systemic effects in peripheral organs by influencing their metabolic homeostasis. Furthermore, many of the dietary fat-modulated genes and biological processes in small intestine were previously already associated with obesity and/or insulin resistance. Together, the data of this exploratory study provided various leads for an essential role of the small intestine in development of obesity and/or insulin resistance.
Publication Title
The role of the small intestine in the development of dietary fat-induced obesity and insulin resistance in C57BL/6J mice.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 9 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Red meat consumption is associated with an increased colon cancer risk. Heme, present in red meat, injures the colon surface epithelium by luminal cytotoxicity and reactive oxygen species. This surface injury is compensated by hyperproliferation and hyperplasia of crypt cells, which was induced by a changed surface to crypt signalling as recently described. It is unknown whether the change in signaling is caused by cytotoxic stress and/or by oxidative stress, as these processes were never studied separately. Therefore, the aim of this study was to determine the possible differential effects of dietary heme on these luminal stressors and their impact on the colonic mucosa after 2, 4, 7 and 14 days of heme feeding. Mice received a purified humanized control diet or this diet supplemented with 0.2 mol heme/g. Oxidative stress was measured as Thiobarbituric Acid Reactive Substances (TBARS) in fecal water. Cytotoxicity of fecal water was quantified with a bioassay. Epithelial cell proliferation was determined by Ki67 immunohistochemistry and mucosal responses were further studied in detail by whole genome transcriptomics. Dietary heme caused instantaneous and delayed changes in the luminal contents which were reflected in the mucosa. Instantaneous, there was an increase in reactive oxygen species leading to increased levels of lipid peroxidation products. Mucosal gene expression showed an instantaneous antioxidant response and PPAR target gene activation. After day 4 cytotoxicity of the colonic contents was increased and hyperproliferation was initiated, indicating that cytotoxicity was causal for the initiation of hyperproliferation. Several oncogenes were activated and tumor protein 53 was inhibited. In conclusion, dietary heme caused an instantaneous production of reactive oxygen species in mouse colon. A lag time was observed in the formation of cytotoxicity which coincided with the initiation hyperproliferation.
Publication Title
Dietary heme induces acute oxidative stress, but delayed cytotoxicity and compensatory hyperproliferation in mouse colon.
Sample Metadata Fields
Sex, Specimen part, Time
View Samples- Mus musculus
- 18 Downloadable Samples
- Affymetrix Mouse Gene 1.1 ST Array (mogene11st)
Description
Colorectal cancer risk is associated with diets high in red meat. Heme, the pigment of red meat, induces cytotoxicity of colonic contents and elicits epithelial damage and compensatory hyperproliferation, leading to hyperplasia. Here we explore the possible causal role of the gut microbiota in heme-induced hyperproliferation. To this end, mice were fed a purified control or heme diet (0.5 mol/g heme) with or without broad-spectrum antibiotics for 14 d. Heme-induced hyperproliferation was shown to depend on the presence of the gut microbiota, because hyperproliferation was completely eliminated by antibiotics, although heme-induced luminal cytotoxicity was sustained in these mice. Colon mucosa transcriptomics revealed that antibiotics block heme-induced differential expression of oncogenes, tumor suppressors, and cell turnover genes, implying that antibiotic treatment prevented the heme-dependent cytotoxic micelles to reach the epithelium. Our results indicate that this occurs because antibiotics reinforce the mucus barrier by eliminating sulfide-producing bacteria and mucin-degrading bacteria (e.g., Akkermansia). Sulfide potently reduces disulfide bonds and can drive mucin denaturation and microbial access to the mucus layer. This reduction results in formation of trisulfides that can be detected in vitro and in vivo. Therefore, trisulfides can serve as a novel marker of colonic mucolysis and thus as a proxy for mucus barrier reduction. In feces, antibiotics drastically decreased trisulfides but increased mucin polymers that can be lysed by sulfide. We conclude that the gut microbiota is required for heme-induced epithelial hyperproliferation and hyperplasia because of the capacity to reduce mucus barrier function.
Publication Title
Gut microbiota facilitates dietary heme-induced epithelial hyperproliferation by opening the mucus barrier in colon.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples