We report that colon adenomas from ApcMin/+ mice not only exhibit similarities in gene expression profile to colon adenomas from azoxymethane / dextran sulfate sodium-treated mice (with activating Ctnnb1 mutations) due to the activation of canonical WNT signaling, but also unique transcriptional changes in the pathways regulating cell cycle progression / proliferation, chromosome segregation / cytoskeletal organization and apoptosis. Subsequent experiments characterized changes in gene expression unique to colon adenomas from ApcMin/+ mice including increases in the H2afv, Map6 and Nsmf transcripts. Overall design: Examination of gene expression profiles in 2 different colon adenoma types with activated canonical WNT signaling, relative to their respective non-adenoma controls
Mutational Mechanisms That Activate Wnt Signaling and Predict Outcomes in Colorectal Cancer Patients.
Cell line, Treatment, Subject
View SamplesGene expression data were collected by RNA-seq from HCT-116 cells in the presence or absence of siRNA targeting APC and 1,376 transcripts changed in expression following APC silencing were identified relative to scrambled siRNA-transfected and untreated controls. Overall design: Examination of gene expression under 3 different transfection conditions
Chromatin-associated APC regulates gene expression in collaboration with canonical WNT signaling and AP-1.
Specimen part, Cell line, Treatment, Subject
View SamplesWe report the effect of DKK1 treatment during culture on the length and transcriptome of embryos on day 15 of development, supporting the notion that changes early in development affect later stages of development. Overall design: Bovine embryos were produced in vitro and exposed to either 0 or 100 ng/ml DKK1 from day 5 to 7 of culture. Embryos were transferred on day 7 and recovered on day 15 for evaluation of length and transciptome
Dickkopf-related protein 1 is a progestomedin acting on the bovine embryo during the morula-to-blastocyst transition to program trophoblast elongation.
Treatment, Subject
View SamplesBackground & Aims: Ursodeoxycholic acid (UDCA) attenuates chemical and colitis-induced colon carcinogenesis in animal models. We investigated its mechanism of action on normal intestinal cells, in which carcinogenesis- or inflammation-related alterations do not interfere with the result. Methods: Alterations of gene expression were identified in Affymetrix arrays in isolated colon epithelium of mice fed with a diet containing 0.4% UDCA and were confirmed in the normal rat intestinal cell line IEC-6 by RT-PCR. The effect of the insulin receptor substrate 1 (Irs-1) expression and of ERK phosphorylation on proliferation was investigated in vitro by flow cytometry, western blotting, siRNA-mediated gene suppression or by pharmacological inhibition of the kinase activity. The ERK1-effect on Irs-1 transcription was tested in a reporter system. Results: UDCA-treatment in vivo suppressed potential pro-proliferatory genes including Irs-1 and reduced cell proliferation by more than 30%. In vitro it neutralised the proliferatory signals of IGF-1 and EGF and slowed down the cell cycle. Irs-1 transcription was suppressed due to high ERK1 activation. Both Irs-1 suppression and the persistent high ERK activation inhibited proliferation. Conversely, the decrease of phosphorylation of ERK1 (but not ERK2) or of its expression partially abrogated the inhibitory effects of UDCA. Conclusions: UDCA inhibits proliferation of intestinal epithelial cells by acting upon IGF-1 and EGF pathways and targeting ERK1 and, consequently, Irs-1. The inhibition of these pathways adds a new dimension to the physiological and therapeutic action of UDCA and, since both pathways are activated in inflammation and cancer, suggests new applications of UDCA in chemoprevention and chemotherapy.
UDCA slows down intestinal cell proliferation by inducing high and sustained ERK phosphorylation.
Specimen part, Cell line
View SamplesBackground: Sepsis involves aberrant immune responses to infection, but the exact nature of this immune dysfunction remains poorly defined. Bacterial endotoxins like lipopolysaccharide (LPS) are potent inducers of inflammation, which has been associated with the pathophysiology of sepsis, but repeated exposure can also induce a suppressive effect known as endotoxin tolerance or cellular reprogramming. It has been proposed that endotoxin tolerance might be associated with the immunosuppressive state that was primarily observed during late-stage sepsis. However, this relationship remains poorly characterised. Here we clarify the underlying mechanisms and timing of immune dysfunction in sepsis. Methods: We defined a gene expression signature characteristic of endotoxin tolerance. Gene-set test approaches were used to correlate this signature with early sepsis, both newly and retrospectively analysing microarrays from 593 patients in 11 cohorts. Then we recruited a unique cohort of possible sepsis patients at first clinical presentation in an independent blinded controlled observational study to determine whether this signature was associated with the development of confirmed sepsis and organ dysfunction. Findings: All sepsis patients presented an expression profile strongly associated with the endotoxin tolerance signature (p < 0.01; AUC 96.1%). Importantly, this signature further differentiated between suspected sepsis patients who did, or did not, go on to develop confirmed sepsis, and predicted the development of organ dysfunction. Interpretation: Our data support an updated model of sepsis pathogenesis in which endotoxin tolerance-mediated immune dysfunction (cellular reprogramming) is present throughout the clinical course of disease and related to disease severity. Thus endotoxin tolerance might offer new insights guiding the development of new therapies and diagnostics for early sepsis. Overall design: For the RNA-Seq study reported here, 73 patients were recruited with deferred consent at the time of first examination in an emergency ward based on the opinion of physicians that there was a potential for the patient''s condition to develop into sepsis. These were retrospectively divided into groups based on clinical features and compared to 11 non-urgent surgical controls.
An Endotoxin Tolerance Signature Predicts Sepsis and Organ Dysfunction at Initial Clinical Presentation.
No sample metadata fields
View SamplesBackground: Dendritic cells (DCs) are critical for regulating CD4 and CD8 T cell immunity, controlling Th1, Th2, and Th17 bias, generating inducible Tregs, and inducing tolerance. Multiple DC subsets have been identified in the mouse that are thought to have evolved to control these different immune outcomes. However, how these subsets differentially respond to inflammatory and/or tolerogenic signals in order to accomplish their divergent functionality remains unclear. Results: We analysed the responses of murine, splenic CD8 and CD11b DC subsets to in-vivo stimulation with lipopolysaccharide using RNA-Seq and systems biology approaches and observed responses are highly subset-specific. We reanalysed multiple datasets from the literature and show that these subset responses are obscured when analysing signaling at the population level. We show that the subset-specificity is due to the unique regulation of distinct TLR4 pathway modulators that ‘fine-tune’ a common TLR4 cascade rather and not due to major differences in signaling pathways or transcription factors. Conclusions: We propose the Pathway Modulation Model wherein common signaling pathways are regulated by unique sets of modulators allowing for distinct immune responses in closely related DC subsets. We extend these observations using analagous datasets from the literature and show that our model provides a global mechanism for generating cell subset-specific signaling in multiple subpopulations in mouse and man. Overall design: Splenic CD8 and CD11b DC subsets from LPS stimulated (10 pooled animals) and Control (5 pooled animals) mice were analysed by RNA-Seq.
A systems biology approach to the analysis of subset-specific responses to lipopolysaccharide in dendritic cells.
Specimen part, Cell line, Subject, Time
View SamplesOxaliplatin (oxPt) resistance in colorectal cancers (CRC) is a major medical problem, and predictive markers are urgently needed. Recently, miR-625-3p was reported as a promising predictive marker. Here, we have used in vitro models to show that miR-625-3p functionally induces oxPt resistance in CRC cells, and have identified signalling networks affected by miR-625-3p. The p38 MAPK activator MAP2K6 was shown to be a direct target of miR-625-3p, and, accordingly, was downregulated in patients not responding to oxPt therapy. miR-625-3p resistance could be reversed in CRC cells by anti-miR-625-3p treatment and by ectopic expression of a miR-625-3p insensitive MAP2K6 variant. In addition, by reducing p38 MAPK signalling using either siRNA technology, chemical inhibitors to p38 or by ectopic expression of dominant negative MAP2K6 protein we induced resistance to oxPt. Transcriptome, proteome and phosphoproteome profiles revealed inactivation of MAP2K6-p38 signalling as one likely mechanism a possible driving force behind of oxPt resistance. Our study shows that miR-625-3p induces oxPt resistance by abrogating MAP2K6-p38 regulated apoptosis and cell cycle control networks, and corroborates the predictive power of miR-625-3p
miR-625-3p regulates oxaliplatin resistance by targeting MAP2K6-p38 signalling in human colorectal adenocarcinoma cells.
Subject
View SamplesSirtuin-1 (Sirt1), a class III histone/protein deacetylase is central to cellular metabolism, stress responses and aging, but its contributions to various host immune functions have been little investigated. To study the role of Sirt1 in T-cell functions, we undertook targeted deletions by mating mice with a floxed Sirt1 gene to mice expressing CD4-cre or Foxp3-cre recombinase, respectively. We found that Sirt1 deletion left conventional T-effector cell activation, proliferation and cytokine production largely unaltered. However, Sirt1 targeting promoted the expression and acetylation of Foxp3, a key transcription factor in T-regulatory (Treg) cells, and increased Treg suppressive functions in vitro and in vivo. Consistent with these data, mice with targeted deletions of Sirt1 in either CD4+ T-cells or Foxp3+ Treg cells exhibited prolonged survival of MHC-mismatched cardiac allografts. Allografts in Sirt1 targeted recipients showed long-term preservation of myocardial histology and infiltration by Foxp3+ Treg cells. Comparable results were seen in wild-type allograft recipients treated with Sirt1 inhibitors, such as EX-527 and splitomicin. Hence, Sirt1 may inhibit Treg functions and its targeting may have therapeutic value in autoimmunity and transplantation.
Sirtuin-1 targeting promotes Foxp3+ T-regulatory cell function and prolongs allograft survival.
Specimen part
View SamplesTargeting histone/protein deacetylase (HDAC)-6, -9, or Sirtuin-1 (Sirt1) augments the suppressive functions of Foxp3+ T regulatory (Treg) cells, but it is unclear if this involves different mechanisms, such that combined inhibition would be beneficial. We compared the suppressive functions of Tregs from wild-type C57BL/6 mice or mice with global (HDAC6-/-, HDAC9-/-, dual HDAC6/9-/-) or conditional deletion (CD4-Cre or Foxp3-Cre and floxed Sirt1; GSE26425) alone, or after treatment with isoform-selective HDAC inhibitors (HDACi). We found the heat shock response was crucial in mediating the effects of HDAC6, but not Sirt1 inhibition. Furthermore, while HDAC6, HDAC9 and Sirt1 all deacetylate Foxp3, each has diverse effects on Foxp3 transcription, and loss of HDAC9 is associated with stabilization of Stat5 acetylation and its transcriptional activity. Targeting different HDAC can increase Treg function by multiple and additive mechanisms, indicating the therapeutic potential for combinations of HDACi in the management of autoimmunity and alloresponses post-transplant.
Histone deacetylases 6 and 9 and sirtuin-1 control Foxp3+ regulatory T cell function through shared and isoform-specific mechanisms.
No sample metadata fields
View SamplesWe investigated the role of DNMT1 in immune homeostasis by generating mice lacking DNMT1 in Foxp3+ T-regulatory (Treg) cells. These mice showed decreased peripheral Foxp3+ Tregs, complete loss of Foxp3+ Treg suppressive functions in vitro and in vivo, and died from autoimmunity by 3-4 weeks unless they received perinatal transfer of wild-type Tregs that prolonged their survival. Methylation of CpG-sites in the TSDR region of Foxp3 was unaffected by DNMT1 deletion, but microarray revealed more >500 proinflammatory and other genes were upregulated in DNMT1-/- Tregs. CD4-Cre-mediated DNMT1 deletion showed inability of conventional T cells to convert to Foxp3+ Treg under appropriate polarizing conditions. Hence, DNMT1 is absolutely necessary for maintenance of the gene program required for normal Treg development and function.
Foxp3+ T-regulatory cells require DNA methyltransferase 1 expression to prevent development of lethal autoimmunity.
Specimen part
View Samples