Translation and mRNA decay are intimately connected processes, and translational inhibition often precedes and stimulates transcript degradation. Here, we have focused on methods that allow determination of mRNA stability on a transcriptome-wide scale. We describe experimental and computational methods for the two most commonly used approaches (transcriptional inhibition and metabolic labeling), and we discuss associated caveats. Overall design: Metabolic labeling time courses (1, 2, 4, 8, 12, 24 hr) using 4SU were performed in HEK293.
Determining mRNA half-lives on a transcriptome-wide scale.
Treatment, Subject
View SamplesPioneering studies within the last few years have allowed the in vitro expansion of tissue-specific adult stem cells from a variety of endoderm-derived organs, including the stomach, small intestine and colon. Here we derived organoids from mouse gallbladder tissue (gallbladder organoids), from mouse liver (including the extrahepatic biliary ducts and gallbladder; liver organoids) and from mouse small intestine tissue (intestinal organoids). RNA was prepared from these organoids and used to assay expression of 21,258 genes using Affymetrix gene expression arrays. RNA was also prepared from mouse gallbladder, liver and small intestine tissues and used to assay gene expression in these tissues. Finally, gallbladder organoids were induced to differentiate by removing R-spondin 1 and noggin from the culture media and subjected to gene expression array analysis.
R-spondin 1 and noggin facilitate expansion of resident stem cells from non-damaged gallbladders.
Specimen part
View SamplesProfiling of the transcriptome of FITChigh/FSCdim and FITCdim/FSChigh sub-populations. Three biological replicates were profiled for each cell type. Overall design: Profiling of the transcriptome of FITChigh/FSCdim and FITCdim/FSChigh sub-populations. Three biological replicates were profiled for each cell type.
An autofluorescence-based method for the isolation of highly purified ventricular cardiomyocytes.
Specimen part, Cell line, Subject
View SamplesNatural Killer (NK) cells are the first lymphocyte population to reconstitute early after non myelo-ablative and T cell-replete haploidentical hematopoietic stem cell transplantations (h-HSCTs) with post-transplant infusion of cyclophosphamide. The present study characterizes the transient and predominant expansion starting from the 2nd week after h-HSCT of a donor-derived unconventional subset of CD56dim/CD16neg (uCD56dim) NK cells expressing remarkable high levels of NKG2A and low levels of NKp46. Both transcription and phenotypic profiles indicated that uCD56dim NK cells are a distinct NK cell subpopulation with features of late differentiation, yet retaining proliferative capability and functional plasticity to generate conventional CD56bright/CD16pos NK cells in response to IL-15 plus IL-18. uCD56dim NK cells represent by far the largest NK cell subset detectable in the following 7 weeks after h-HSCT and they also express high levels of the activating receptors NKGD and NKp30 as well as of the lytic granules Granzyme-B and Perforin. Nonetheless, uCD56dim NK cells displayed a defective cytotoxicity that could be reversed by blocking the inhibitory receptor CD94/NKG2A. These data open new important perspectives to better understand the ontogenesis/homeostasis of human NK cells and to develop a novel immune-therapeutic approach by targeting the inhibitory NKG2A check point, thus enhancing NK cell alloreactivity early after h-HSCT.
The early expansion of anergic NKG2A<sup>pos</sup>/CD56<sup>dim</sup>/CD16<sup>neg</sup> natural killer represents a therapeutic target in haploidentical hematopoietic stem cell transplantation.
Specimen part
View SamplesPro-inflammation triggered by microbial lipopolysaccharide (LPS) through Toll-like receptor (TLR) 4 in the presence of interferon (IFN)-g induces cytokine secretion in dendritic cells (DCs) tightly regulated by a defined differentiation program. This DC differentiation is characterized by a dynamic immune activating but also tolerance inducing phenotype associated with irreversible down-modulation of cytokines. CD40L on activated T cells further modifies DC differentiation. Using DNA micro arrays we showed down-regulated mRNA levels of TLR signaling molecules while CD40/CD40L signaling molecules were up-regulated at a time when LPS/IFN-g activated DCs have ceased cytokine expression. Accordingly we demonstrated that CD40/CD40L but not TLR4 or TLR3 signaling mediated by LPS or poly (cytidylic-inosinic) acid (poly I:C) and dsRNA re-established the capacity to secret interleukin (IL)-12 in LPS/IFN-g activated DCs, which have exhausted their potential for cytokine secretion. This resulting TH1 polarizing DC phenotype which lacked accompanying secretion of the crucial immune suppressive IL-10 - enhanced activation of cytotoxic T lymphocytes (CTLs). We therefore conclude that immune modulation is restricted to a secondary T-cell mediated stimulus at an exhausted DC state which prevents an immune tolerant DC phenotype. These findings impacts on the rational design of TLR activated DC-based cancer vaccines for the induction of anti-tumoral CTL responses.
CD40 ligation restores type 1 polarizing capacity in TLR4-activated dendritic cells that have ceased interleukin-12 expression.
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BET inhibitor resistance emerges from leukaemia stem cells.
Specimen part, Cell line
View SamplesBromodomain and Extra Terminal protein (BET) inhibitors are first-in-class targeted therapies that deliver a new therapeutic paradigm by directly targeting epigenetic readers. Early clinical trials have shown significant promise especially in acute myeloid leukaemia (AML)3; therefore the evaluation of resistance mechanisms, an inevitable consequence of cancer therapies, is of utmost importance to optimise the clinical efficacy of these drugs. Using primary murine stem and progenitor cells immortalised with MLL-AF9, we have used an innovative approach to generate 20 cell lines derived from single cell clones demonstrating stable resistance, in vitro and in vivo, to the prototypical BET inhibitor, I-BET. Resistance to I-BET confers cross-resistance to chemically distinct BET inhibitors such as JQ1, as well as resistance to genetic knockdown of BET proteins. Resistance is not mediated through increased drug efflux or metabolism but is demonstrated to emerge from leukaemia stem cells (LSC). Resistant clones display a leukaemic granulocyte-macrophage progenitor (L-GMP) phenotype (Lin-, Sca-, cKit+, CD34+, FcRII/RIII+) and functionally exhibit increased clonogenic capacity in vitro and markedly shorter leukaemia latency in vivo. Chromatin bound BRD4 is globally reduced in resistant cells, however expression of key target genes such as MYC remains unaltered, highlighting the existence of alternative mechanisms to regulate transcription. We demonstrate that resistance to BET inhibitors is in part a consequence of increased Wnt/-catenin signaling. Negative regulation of this pathway results in differentiation of resistant cells into mature leukaemic blasts, inhibition of MYC expression and restoration of sensitivity to I-BET in vitro and in vivo. Finally, we show that the sensitivity of primary human AML cells to I-BET correlates with the baseline expression of Wnt/-catenin target genes. Together these findings provide novel insights into the biology of AML, highlight the potential therapeutic limitations of BET inhibitors and identify strategies that may overcome resistance and enhance the clinical utility of these unique targeted therapies.
BET inhibitor resistance emerges from leukaemia stem cells.
Specimen part, Cell line
View SamplesCentral to the molecular pathogenesis of MLL leukaemia is the abnormal co-optation of members of transcription complexes including disrupter of telomeric silencing 1-like (DOT1L) and bromodomain containing protein 4 (BRD4). Consequently, targeted therapies against DOT1L and BRD4 are currently being evaluated in clinical trials. However, the mechanisms by which BRD4 and DOT1L regulate leukaemogenic transcription programs remain unclear. Using quantitative proteomics, chemoproteomics and biochemical fractionation we find that native BRD4 and DOT1L exist in largely separate protein complexes. Genetic disruption or small molecule inhibition of BRD4 and DOT1L shows marked synergistic activity against MLL-FP leukaemia cell lines, primary human leukaemia cells and murine leukaemia models. Mechanistically, we find a previously unrecognised functional collaboration between DOT1L and BRD4 that is especially important at highly transcribed genes in close proximity to superenhancers. DOT1L via H3K79me2 facilitates the deposition of histone H4 acetylation, which in turn regulates the binding of BRD4 to chromatin. These data provide novel insights into the regulation of transcription and specify a molecular framework for therapeutic intervention in this poor prognostic disease. Overall design: RNASeq of MV4;11 cells transduced with scramble shRNA or BRD4 shRNA in combination with DMSO or SGC0946 in triplicate
Functional interdependence of BRD4 and DOT1L in MLL leukemia.
Specimen part, Cell line, Subject
View SamplesCentral to the molecular pathogenesis of MLL leukaemia is the abnormal co-optation of members of transcription complexes including disrupter of telomeric silencing 1-like (DOT1L) and bromodomain containing protein 4 (BRD4). Consequently, targeted therapies against DOT1L and BRD4 are currently being evaluated in clinical trials. However, the mechanisms by which BRD4 and DOT1L regulate leukaemogenic transcription programs remain unclear. Using quantitative proteomics, chemoproteomics and biochemical fractionation we find that native BRD4 and DOT1L exist in largely separate protein complexes. Genetic disruption or small molecule inhibition of BRD4 and DOT1L shows marked synergistic activity against MLL-FP leukaemia cell lines, primary human leukaemia cells and murine leukaemia models. Mechanistically, we find a previously unrecognised functional collaboration between DOT1L and BRD4 that is especially important at highly transcribed genes in close proximity to superenhancers. DOT1L via H3K79me2 facilitates the deposition of histone H4 acetylation, which in turn regulates the binding of BRD4 to chromatin. These data provide novel insights into the regulation of transcription and specify a molecular framework for therapeutic intervention in this poor prognostic disease. Overall design: RNASeq of MLL-AF9 cells transduced with scramle shRNA or BRD4 shRNA in combination with DMSO or SGC0946 in triplicate
Functional interdependence of BRD4 and DOT1L in MLL leukemia.
Specimen part, Cell line, Treatment, Subject
View SamplesThe success of targeted therapies hinges on our ability to understand the molecular and cellular mechanism of action of these agents. Here we modify various BET bromodomain inhibitors, an exemplar novel targeted therapy, to create functionally conserved compounds that are amenable to click-chemistry and can be used as molecular probes in vitro and in vivo. Using click-proteomics and click-sequencing we provide new mechanistic insights to explain the gene regulatory function of BRD4 and the transcriptional changes invoked by BET inhibitors. In mouse models of acute leukaemia, we use high resolution microscopy and flow cytometry to highlight the underappreciated heterogeneity of drug activity within tumour cells located in different tissue compartments. We also demonstrate the differential distribution and effects of the drug in normal and malignant cells in vivo. These data provide critical insights that reveal the cellular and molecular details for the efficacy and limitations of these agents. This study provides a framework for the pre-clinical assessment of other conventional and targeted therapies. Overall design: RNASeq of MV4;11 cell treated with DMSO, JQ1 or JQ1–PA
Click chemistry enables preclinical evaluation of targeted epigenetic therapies.
Specimen part, Cell line, Subject
View Samples