To define target genes of the intestine-restricted transcription factor (TF) CDX2 in intestinal stem cells, we performed chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq). We used RNA-sequencing to profile gene expression changes during cell differentiation from mouse intestinal stem cells to mature villus cells, as well as genes perturbed in intestinal stem cells upon loss of Cdx2. We find thousands of genes that change in expression during cell differentiation, including known stem cell and mature markers. Upon loss of Cdx2, hundreds of genes are up and down-regulated in intestinal stem cells, some of which are also bound by CDX2 nearby and constitute candidate direct target genes. Overall design: CDX2 ChIP-Seq analysis of isolated mouse intestinal stem cells. RNA seq analysis of control mouse villus cells, control intestinal stem cells and Cdx2-deleted intestinal stem cells.
Distinct Processes and Transcriptional Targets Underlie CDX2 Requirements in Intestinal Stem Cells and Differentiated Villus Cells.
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View SamplesHere we describe a method for fabricating a primary human Small Intestine-on-a-Chip (Intestine Chip) containing epithelial cells isolated from healthy regions of intestinal biopsies. The primary epithelial cells are expanded as 3D organoids, dissociated, and cultured on a porous membrane within a microfluidic device with human intestinal microvascular endothelium cultured in a parallel microchannel under flow and cyclic deformation. In the Intestine Chip, the epithelium forms villi-like projections lined by polarized epithelial cells that undergo multi-lineage differentiation similar to that of intestinal organoids, however, these cells expose their apical surfaces to an open lumen and interface with endothelium. Transcriptomic analysis also indicates that the Intestine Chip more closely mimics whole human duodenum in vivo when compared to the duodenal organoids used to create the chips. Because fluids flowing through the lumen of the Intestine Chip can be collected continuously, sequential analysis of fluid samples can be used to quantify nutrient digestion, mucus secretion and establishment of intestinal barrier function over a period of multiple days in vitro. The Intestine Chip therefore may be useful as a research tool for applications where normal intestinal function is crucial, including studies of metabolism, nutrition, infection, and drug pharmacokinetics, as well as personalized medicine.
Development of a primary human Small Intestine-on-a-Chip using biopsy-derived organoids.
Specimen part
View SamplesBACKGROUND & AIMS: Inflammatory Bowel Disease (IBD) is a chronic inflammatory condition driven by loss of homeostasis between the mucosal immune system, the commensal gut microbiota, and the intestinal epithelium. Our overarching goal is to understand how these components of the intestinal ecosystem cooperate to control homeostasis and to identify novel signal transduction pathways that become dysregulated in IBD. METHODS: We have applied a multi-scale systems biology approach to a mouse model of chronic colitis. We combined quantitative measures of epithelial hyperplasia and immune infiltration with multivariate analysis of inter- and intra-cellular signaling molecules in order to generate a tissue level model of the inflamed disease state. We utilized the computational model to identify signaling pathways that were dysregulated in the context of colitis and then validated model predictions by measuring the effect of small molecule pathway inhibitors on colitis. RESULTS: Our data-driven computational model identified mTOR signaling as a potential driver of inflammation and mTOR inhibition reversed the molecular, immunological, and epithelial manifestations of colitis. Inhibition of Notch signaling, which induces epithelial differentiation, had the same effect, suggesting that the epithelial proliferation/differentiation state plays a key role in maintaining homeostasis of the colon. Confirming this, we found that colonic organoids grown ex vivo showed a similar relationship between proliferation and cytokine expression, even in the absence of gut bacteria and immune cells. CONCLUSIONS: Our study provides a tissue-level systems biology perspective of murine colitis and suggests that mTOR plays a key role in regulating colonic homeostasis by controlling epithelial proliferation/differentiation state.
The colonic epithelium plays an active role in promoting colitis by shaping the tissue cytokine profile.
Specimen part
View SamplesWe demonstrate that PKA signalling drives zonal conversion within adult adrenocortical lineage in a sexually dimorphic manner. Our data establish that Prkar1a genetic ablation (leading to constitutive PKA activation) in the adult adrenocortical lineage leads to endocrine hyperactivity and accelerates adrenal cortex renewal. This results in increased zona fasciculata differentiation and final conversion into reticularis-like zone. This phenomenon relies partly on sex-dependent mechanisms of cortical renewal, on which the male androgenic milieu exerts a repressive action through induction of WNT signalling, which in turn antagonizes PKA signalling and cortical cell turnover.
PKA signaling drives reticularis differentiation and sexually dimorphic adrenal cortex renewal.
Sex, Specimen part
View SamplesA comparative bulk cell RNA-seq analysis of diverse intestinal stem cell populations was performed, for cells expressing the following markers: Lgr5-eGFPhi, Cd166+, Cd24lo, Grp78, upper side population (SP), Bmi1, mTert, Hopx, Dclk1, a lower side population (SP) Overall design: For each ISC population of interest, three independent mice (biological replicates) were used. From each mouse, a marker-“positive” and a marker-“negative” population were collected, as well as a "total" population.
Intestinal Enteroendocrine Lineage Cells Possess Homeostatic and Injury-Inducible Stem Cell Activity.
Disease, Subject
View SamplesAnalysis of gene expression in the meristematic zone of Arabidopsis roots overexpressing miR396
MicroRNA miR396 Regulates the Switch between Stem Cells and Transit-Amplifying Cells in Arabidopsis Roots.
Age, Specimen part
View SamplesRANK-positive and RANK-negative luminal progenitor cells were isolated by FACS from histologically normal human breast tissue from wild-type human donors. RNA-seq gene expression profiling was used to find differentially expressed genes between the RANK-positive and RANK-negative cell populations. Overall design: Cells were isolated from 4 human patients. A paired analysis was used to compare RANK-positive and RANK-negative cells within patients.
RANK ligand as a potential target for breast cancer prevention in BRCA1-mutation carriers.
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View SamplesBRCA1, a well-known breast and ovarian cancer susceptibility gene with multiple interacting partners, is predicted to have diverse biological functions. However, to date its only well-established role is in the repair of damaged DNA and cell cycle regulation. In this regard, the etiopathological study of low penetrant variants of BRCA1 provides an opportunity to uncover its other physiologically important functions. Using this rationale, we studied the R1699Q variant of BRCA1, a potentially moderate risk variant, and found that it does not impair DNA damage repair but abrogates the repression of miR-155, a bona fide oncomir. We further show that in the absence of functional BRCA1, miR-155 is up-regulated in BRCA1-deficient mouse mammary epithelial cells, human and mouse BRCA1-deficienct breast tumor cell lines as well as tumors. Mechanistically, we found that BRCA1 represses miR-155 expression via its association with HDAC2, which deacetylates H2A and H3 on the miR-155 promoter. Finally, we show that over-expression of miR-155 accelerates whereas the knockdown of miR-155 attenuates the growth of tumor cell lines in vivo. Taken together, our findings demonstrate a new mode of tumor suppression by BRCA1 and reveal miR-155 as a potential therapeutic target for BRCA1-deficient tumors.
Tumor suppressor BRCA1 epigenetically controls oncogenic microRNA-155.
Specimen part
View SamplesWe examined the functional significance of the R1699Q variant of human BRCA1 gene using a mouse ES cell-based assay.
Tumor suppressor BRCA1 epigenetically controls oncogenic microRNA-155.
Specimen part
View SamplesAdipose tissue iNKT cells have different functions than iNKT cells in the blood and other organs.
Regulatory iNKT cells lack expression of the transcription factor PLZF and control the homeostasis of T(reg) cells and macrophages in adipose tissue.
Age, Specimen part
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