Background and aims: Dysregulation of intestinal epithelial cells performance associates with an array of pathologies whose onset mechanisms are incompletely understood. The aim of the present study was to provide a map of gene expresssion patterns along the human healthy adult gastro-intestinal tract and to implement a new procedure for microarray data noise filtering that would allow their use as a reference when screening for pathological deviations, such as inflammatory bowel disease (IBD). Methods: Gene expression profiles in antrum, duodenum, jejunum, ileum and transverse colon biopsies were measured with the Affymetrix U133A array and principal component analysis was used to identify region-selective biomarkers. These data were intersected with highly variable genes from a public dataset of gene expression in the ileal and colonic healthy regions of UC and Crohns disease patients. Moreover, gene sets covering gut functions not entirely accounted for by the available public tools were constructed to monitor their expression along the GI tract. Results: 166 genes were found to be responsible for distinguishing the five regions considered. Fourteen had never been described in the GI tract, including a semaphorin probably implicated in pathogen invasion, and six other novel genes. Similar analysis of the IBD datasets revealed that samples stratify based on disease rather than on the intestinal region. This withstanding, eleven genes were identified as possible early predictors of Crohns and/or UC in ileum and/or colon. These include CLCA4 and SLC26A2, both implicated in ion transport. Conclusions: This novel approach, validated by retrieving known gene profiles, allowed the identification of promising new leads both in health and IBD state.
Biomarkers of human gastrointestinal tract regions.
Age
View SamplesDiurnal temperature cycling is an intrinsic characteristic of many exposed microbial ecosystems. However, its influence on yeast physiology and transcriptome has not been studied in detail. In this study, 24-h sinoidal temperature cycles, oscillating between 12 and 30C, were imposed on anaerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae. After three diurnal temperature cycles (DTC), concentrations of glucose, and extracellular metabolites, as well as CO2-production rates showed regular, reproducible circadian rhytms. DTC also led to waves of transcriptional activation and repression, which involved one sixth of the yeast genome. A substantial fraction of these DTC-responsive genes appeared to primarily respond to changes in glucose concentration. Elimination of known glucose-responsive genes revealed overrepresentation of previously identified temperature-responsive genes as well as genes involved in cell cycle and de novo purine biosynthesis. Analyses of budding index and flow cytomery demonstrated that DTC led to a partial synchronization of the cell cycle of the yeast populations in the chemostat cultures, which was lost upon release from DTC. Comparison of DTC results with data from steady-state cultures showed that DTC was sufficiently slow to allow S. cerevisiae chemostat cultures to almost completely acclimatize their transcriptome and physiology at the DTC temperature maximum, and to approach acclimation at the DTC temperature minimum.
Physiological and transcriptional responses of anaerobic chemostat cultures of Saccharomyces cerevisiae subjected to diurnal temperature cycles.
No sample metadata fields
View SamplesSystemic transcriptional responses in Arabidopsis thaliana distal leaves to wounding
The plant NADPH oxidase RBOHD mediates rapid systemic signaling in response to diverse stimuli.
Age, Specimen part
View SamplesWe report gene expression data for FACS sorted zebrafish mpeg1:mCherry + and mpx:EGFP + cells collected from whole embryos at 72 hours post fertilization (hpf). We also report gene expression data for the remaining, transgene negative, portion of these embryos. Overall design: ~1,000 mpeg1:mCherry+; mpx:EGFP+ transgenic embryos were homogenized, filtered, and sorted using FACS into PBS, collecting >50,000 cells for each of the three populations: mpeg1:mCherry+, mpx:EGFP+ and double negative (no double positive cells were collected as there was almost no overlap between mCherry and EGFP expression).
Distinct Roles for Matrix Metalloproteinases 2 and 9 in Embryonic Hematopoietic Stem Cell Emergence, Migration, and Niche Colonization.
No sample metadata fields
View SamplesExpression data from mouse tumor-specific CD4+ T cells
Molecular profiling of tumor-specific T<sub>H</sub>1 cells activated in vivo.
Specimen part
View SamplesThe immune system can both promote and suppress cancer. Chronic inflammation and proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered tumor-promoting. In contrast, the exact nature of protective antitumor immunity remains obscure. In this study, we have quantified locally secreted cytokines during primary immune responses against myeloma and B-cell lymphoma in mice. Strikingly, successful cancer immunosurveillance mediated by tumor-specific CD4+ T cells was consistently associated with elevated local levels of both proinflammatory (IL-1aplha, IL-1beta, and IL-6) and T helper 1 (Th1)-associated cytokines (interferon-alpha, IL-2, IL-12). Cancer eradication was achieved by a collaboration between tumor-specific Th1 cells and tumor-infiltrating, antigen-presenting macrophages. Th1 cells induced secretion of IL-1? and IL-6 by macrophages. Th1-derived interferon-? was shown to render macrophages directly cytotoxic to cancer cells, and to induce macrophages to secrete the angiostatic chemokines CXCL9/MIG and CXCL10/IP-10. Thus, inflammation, when driven by tumor-specific Th1 cells, may prevent rather than promote cancer.
Inflammation driven by tumour-specific Th1 cells protects against B-cell cancer.
Specimen part
View SamplesWe analyzed the generation of mouse gliomas following the overexpression of PDGF-B in embryonic neural progenitors. Comparison of our microarray data, with published gene expression data sets for many different murine neural cell types, revealed a closest relationship between our tumor cells and oligodendrocyte progenitor cells, confirming definitively that PDGF-B-induced gliomas are pure oligodendrogliomas.
PDGF-B induces a homogeneous class of oligodendrogliomas from embryonic neural progenitors.
No sample metadata fields
View SamplesAngioimmunoblastic T-cell lymphoma (AITL) is an aggressive lymphoid tumor derived from malignant transformation of T follicular helper (Tfh) cells. Genetically, AITL is characterized by loss of function mutations in the Ten-Eleven Translocation 2 (TET2) epigenetic tumor suppressor and a highly recurrent mutation (p.Gly17Val, G17V) in the RHOA small GTPase gene Moreover, RHOA G17V expression in Tet2 deficient hematopoietic progenitors resulted in the specific development of lymphoid tumors resembling human AITL. Notably, inhibition of ICOS signaling impaired the growth of RHOA G17V-induced mouse lymphomas in vivo, thus providing a potential new rational approach for the treatment of AITL. Overall design: We analyzed mRNA expression profiles of primary tumor cells expressing Rhoa G17V or Rhoa wild type.
RHOA G17V Induces T Follicular Helper Cell Specification and Promotes Lymphomagenesis.
Specimen part, Subject
View SamplesDNA methylation, histone modifications, and nucleosomal occupancy collaborate to cause silencing of tumor related genes in cancer. The development of drugs that target these processes is therefore important for cancer therapy. Inhibitors of DNA methylation and histone deacetylation have already been approved by the FDA for the treatment of hematologic malignancies. However, drugs that target the other mechanisms still need to be developed. Recently, 3-deazaneplanocin A (DZNep) was reported to selectively inhibit the trimethylation of lysine 27 on histone H3 (H3K27me3) and lysine 20 on histone H4 (H4K20me3) as well as re-activate silenced genes in cancer cells. This finding opens the door to pharmacological inhibition of histone methylation and we therefore wanted to further study the mechanism of action of 3-deazaneplanocin A in cancer cells. Western blot analysis showed that two other drugs, sinefungin and adenosine-dialdehyde (Adox), have similar effects on the trimethylation H3K27 as 3-deazaneplanocin A and that DZNep is not selective, but globally inhibits histone methylation. Intriguingly, chromatin immunoprecipitation of various histone modifications and microarray analysis show DZNep acts via a different pathway to 5-aza-2-deoxycytidine (5-azaCdR), a DNA methyltransferase inhibitor and gives us an interesting insight into how chromatin structure effects gene expression. We also determine the kinetics of gene activation in order to understand if the induced changes were somatically heritable. We have found that upon removal of DZNep, gene expression is reduced to its original state suggesting that there is a homeostatic mechanism which returns the histone modifications to their ground state after DZNep treatment. Not only do these studies show the strong need for further development of histone methylation inhibitors but also allow us to better understand how chromatin structure affects gene expression.
DZNep is a global histone methylation inhibitor that reactivates developmental genes not silenced by DNA methylation.
No sample metadata fields
View SamplesDNA methylation, histone modifications, and nucleosomal occupancy collaborate to cause silencing of tumor related genes in cancer. The development of drugs that target these processes is therefore important for cancer therapy. Inhibitors of DNA methylation and histone deacetylation have already been approved by the FDA for the treatment of hematologic malignancies. However, drugs that target the other mechanisms still need to be developed. Recently, 3-deazaneplanocin A (DZNep) was reported to selectively inhibit the trimethylation of lysine 27 on histone H3 (H3K27me3) and lysine 20 on histone H4 (H4K20me3) as well as re-activate silenced genes in cancer cells. This finding opens the door to pharmacological inhibition of histone methylation and we therefore wanted to further study the mechanism of action of 3-deazaneplanocin A in cancer cells. Western blot analysis showed that two other drugs, sinefungin and adenosine-dialdehyde (Adox), have similar effects on the trimethylation H3K27 as 3-deazaneplanocin A and that DZNep is not selective, but globally inhibits histone methylation. Intriguingly, chromatin immunoprecipitation of various histone modifications and microarray analysis show DZNep acts via a different pathway to 5-aza-2-deoxycytidine (5-azaCdR), a DNA methyltransferase inhibitor and gives us an interesting insight into how chromatin structure effects gene expression. We also determine the kinetics of gene activation in order to understand if the induced changes were somatically heritable. We have found that upon removal of DZNep, gene expression is reduced to its original state suggesting that there is a homeostatic mechanism which returns the histone modifications to their ground state after DZNep treatment. Not only do these studies show the strong need for further development of histone methylation inhibitors but also allow us to better understand how chromatin structure affects gene expression.
DZNep is a global histone methylation inhibitor that reactivates developmental genes not silenced by DNA methylation.
Cell line
View Samples