Project description:microRNA profiling of rat small intestinal crypt cell IEC-6. Comparing control untreated with cells treated with transforming growth factor-beta (TGF-beta). TGF-beta stimulated cell differentiation, as observed in the stimulation of intestinal epithelial cell markers (alkaline phophotase, villin, aminopeptidase N, etc.). Two condition experiment. Control vs TGF-beta treatment. Biological replicates: 3 control, 3 treated. Independently grown and harvested. One replicate per array
Project description:microRNA profiling of rat small intestinal crypt cell IEC-6. Comparing control untreated with cells treated with transforming growth factor-beta (TGF-beta). TGF-beta stimulated cell differentiation, as observed in the stimulation of intestinal epithelial cell markers (alkaline phophotase, villin, aminopeptidase N, etc.).
Project description:Depending on the tumor type IκB kinase α (IKKα) can act as tumor promoter or tumor suppressor in various malignancies. Here we demonstrate a key function of IKKα in the suppression of a tumoricidal microenvironment during intestinal carcinogenesis. Mice deficient in IKKα kinase activity are largely protected from intestinal tumor development that is dependent on the enhanced recruitment of IFNγ expressing M1-like myeloid cells. In IKKα mutant mice M1-like polarization is not controlled in a cell autonomous manner but depends rather on the interplay of both IKKα mutant tumor epithelia and immune cells. Tamoxifen-inducible β-catc.a. mice comprise an excellent model to study Wnt-dependent tumor initiation. These mice are characterized by IEC-restricted stabilization of β-catenin causing rapid expansion of intestinal crypts and loss of differentiated IEC. To further explore the underlying IKKα controlled pro-proliferative mechanism, we performed a microarray analysis comparing RNA isolated from wildtype, IkkαAA/AA, β-catc.a. or β-catc.a./IkkαAA/AA IEC 15 days after the first tamoxifen administration. and within 4 weeks β-catc.a. mice succumb to this marked crypt hyperproliferation
Project description:The intestine is the critical organ not only for processing and resorbing nutrients from ingested food but also for defending the organism from external stresses such as pathogens. These functions are mainly carried out by the epithelium which is constantly being self-renewed throughout adult life. Intestinal epithelial homeostasis is maintained through well-controlled cell proliferation of the stem cells and transient amplifying cells and the apoptotic degeneration of epithelial cells, mostly at or near the tip of the villi. Many genes and pathways have been found to influence intestinal epithelial cell proliferation. Among them is the mTORC1 signaling pathway, whose activation is known to increase cell proliferation. Here, we report the first intestinal epithelial specific knockout (IEC-KO) of an amino acid transporter capable of activating mTORC1. We show that the transporter, slc7a5, is highly expressed in the intestinal crypt and slc7a5 IEC-KO leads to expected reduction in mTORC1 signal in the crypt or even in intestinal organoids in vitro. Surprisingly, slc7a5 IEC-KO leads to increased proliferation of both transit amplifying cells and crypt base stem cells but a reduction in the secretory cells, particularly mature Paneth cells in the crypt base. Our scRNA-seq and electron microscopic analyses reveals that slc7a5 IEC-KO causes dedifferentiation of the Paneth cells, leading to drastically reduced secretory granules and lysozyme expression without affecting the overall Paneth cell number. We further show that slc7a5 IEC-KO mice are prone to induced colitis due to this loss of Paneth cell differentiation. We propose a model where slc7a5 regulates secretory cell differentiation to affect stem cell niche and/or inflammatory response to regulate cell proliferation in the crypts.
Project description:RIE (rat intestinal epithelial) cells treated with 2 ng/ml of TGF-beta-1 for 1 hr were compared to control cells. The experiment was performed under identical conditions four times: RIE vs RIE - TGF-beta #1-#4. RIE-Ras cells were established by stable transfection of the parental cells with pSV2-H-Ras(12V) which contain human sequences encoding the constitutively active H-Ras(12V) protein. RIE-Ras cells treated with 2 ng/ml of TGF-beta-1 for 1 hr were compared to control cells. The experiment was performed four times under identical conditions (RIE-Ras vs RIE-RAS TGF-beta #1-#4). Keywords = TGF-beta Keywords = rat Keywords = intestinal epithelial cells Keywords: parallel sample
Project description:Intestinal epithelium are generated by intestinal stem cells, which are recognized morphologically as slender columnar cells at the base of the crypt. Stem cells produce transit-amplifying (TA) cells, which divide a number of times and the daughter cells differentiate into absorptive enterocytes as well as secretory-lineages. Intestinal stem cells highly express Lgr5 which is decreased in TA cells. Here, we show that the zinc transported SLC39A7/ZIP7 is essential for the proliferation of TA cells and maintenance of intestinal stem cells. Lgr5Med TA cells derived from Zip7-deficient mice upregulated the expression of unfold protein responses-related genes including pro-apoptotic genes, indicating of induction of ER stress in these cells. The same effect was seen in Lgr5Hi stem cells derived from Zip7-deficient mice. We conclude that ZIP7 is fundamental to the maintenance of crypt homeostasis by resolving ER stress. Small intestinal crypts were isolated form tamoxifen-treated control (Zip7flox/+, Villin-CreERT2, Lgr5-EGFP-ires-CreERT2) and tamoxifen-treated Zip7â??IEC (Zip7flox/flox, Villin-CreERT2, Lgr5-EGFP-ires-CreERT2) mice. We FACS purified intestinal crypt cells according to their Lgr5 expression levels. RNA was isolated from four FACS sorted cell populations: Lgr5Hi cells and Lgr5Med cells derived from control mice, Lgr5Hi cells and Lgr5Med cells derived from Zip7â??IEC mice. Isolated RNA was analyzed using the Affymetrix platform.
Project description:The Wnt signaling pathway is deregulated in over 90% of human colorectal cancers. β Catenin, the central signal transducer of the Wnt pathway, can directly modulate gene expression by interacting with transcription factors of the TCF/LEF-family. In the present study we investigate the role of Wnt signaling in the homeostasis of intestinal epithelium using tissue-specific, inducible beta-catenin gene ablation in adult mice. Block of Wnt/beta-catenin signaling resulted in rapid loss of transient-amplifying cells and crypt structures. Importantly, intestinal stem cells were induced to terminally differentiate upon deletion of beta-catenin resulting in a complete block of intestinal homeostasis and fatal loss of intestinal function. Transcriptional profiling of mutant crypt mRNA isolated by laser capture micro dissection confirmed those observations and allowed to identify genes potentially responsible for the functional preservation of intestinal stem cells. Experiment Overall Design: laser capture microdissection of intestinal crypts, control vs. beta-catenin mutant (2days after induction of deletion by tamoxifen), two rounds of amplification of mRNA