Pro-inflammatory T cells-derived cytokines enhance the maturation of the human fetal intestinal epithelial barrier.

Small intestine (SI) maturation during early life is pivotal in preventing the onset of gut diseases. In this study we interrogated the milestones of SI development by gene expression profiling and ingenuity pathway analyses. We identified a set of cytokines as main regulators of changes observed across different developmental stages.

Grp78 is required for intestinal Kras-dependent glycolysis proliferation and adenomagenesis.

In development of colorectal cancer, mutations in are often followed by mutations in oncogene The latter changes cellular metabolism and is associated with the Warburg phenomenon. Glucose-regulated protein 78 () is an important regulator of the protein-folding machinery, involved in processing and localization of transmembrane proteins. We hypothesize that targeting in and ()-mutant intestines interferes with the metabolic phenotype imposed by mutations.

Differential and organ-specific functions of organic solute transporter α and β in experimental cholestasis.

Background & Aims: Organic solute transporter (OST) subunits OSTα and OSTβ facilitate bile acid efflux from the enterocyte into the portal circulation. Patients with deficiency of OSTα or OSTβ display considerable variation in the level of bile acid malabsorption, chronic diarrhea, and signs of cholestasis. Herein, we generated and characterized a mouse model of OSTβ deficiency.

Altered Gut Structure and Anti-Bacterial Defense in Adult Mice Treated with Antibiotics during Early Life.

The association between prolonged antibiotic (AB) use in neonates and increased incidence of later life diseases is not yet fully understood. AB treatment in early life alters intestinal epithelial cell composition, functioning, and maturation, which could be the basis for later life health effects. Here, we investigated whether AB-induced changes in the neonatal gut persisted up to adulthood and whether early life AB had additional long-term consequences for gut functioning.

Epithelial argininosuccinate synthetase is dispensable for intestinal regeneration and tumorigenesis.

The epithelial signaling pathways involved in damage and regeneration, and neoplastic transformation are known to be similar. We noted upregulation of argininosuccinate synthetase (ASS1) in hyperproliferative intestinal epithelium. Since ASS1 leads to de novo synthesis of arginine, an important amino acid for the growth of intestinal epithelial cells, its upregulation can contribute to epithelial proliferation necessary to be sustained during oncogenic transformation and regeneration.

Applicability of different cell line-derived dendritic cell-like cells in autophagy research.

Background And Aims: Immortalized cell lines have been long used as substitute for ex vivo murine and human material, but exhibit features that are not found in healthy tissue. True human dendritic cells (DC) cannot be cultured or passaged as opposed to immortalized cell lines. Research in the fields of immunogenic responses and immunotolerance in DCs has increased over the last decade.

Early Life Antibiotics Influence In Vivo and In Vitro Mouse Intestinal Epithelium Maturation and Functioning.

Background & Aims: The use of antibiotics (ABs) is a common practice during the first months of life. ABs can perturb the intestinal microbiota, indirectly influencing the intestinal epithelial cells (IECs), but can also directly affect IECs independent of the microbiota. Previous studies have focused mostly on the impact of AB treatment during adulthood.

Endoplasmic reticulum stress regulates the intestinal stem cell state through CtBP2.

Enforcing differentiation of cancer stem cells is considered as a potential strategy to sensitize colorectal cancer cells to irradiation and chemotherapy. Activation of the unfolded protein response, due to endoplasmic reticulum (ER) stress, causes rapid stem cell differentiation in normal intestinal and colon cancer cells. We previously found that stem cell differentiation was mediated by a Protein kinase R-like ER kinase (PERK) dependent arrest of mRNA translation, resulting in rapid protein depletion of WNT-dependent transcription factor c-MYC.

Epithelium-derived Indian Hedgehog restricts stromal expression of ErbB family members that drive colonic tumor cell proliferation.

Indian Hedgehog (Ihh) is a morphogen expressed by epithelial cells in the small intestine and colon that signals in a paracrine manner to gp38+ stromal cells. The loss of Ihh signaling results in increased epithelial proliferation, lengthening and multiplication of intestinal crypts and the activation of a stromal cell immune response. How Ihh controls epithelial proliferation through the stroma and how it affects colorectal cancer development remains poorly defined.

Driver mutations of the adenoma-carcinoma sequence govern the intestinal epithelial global translational capacity.

Deregulated global translation is an emerging feature of cancer cells. Oncogenic transformation in colorectal cancer (CRC) is driven by mutations in , , , and , known as the adenoma-carcinoma sequence (ACS). Here we introduce each of these driver mutations into intestinal organoids to show that they are modulators of global translational capacity in intestinal epithelial cells.

A Novel Organoid Model of Damage and Repair Identifies HNF4α as a Critical Regulator of Intestinal Epithelial Regeneration.

Background & Aims: Recent evidence has suggested that the intact intestinal epithelial barrier protects our body from a range of immune-mediated diseases. The epithelial layer has an impressive ability to reconstitute and repair upon damage and this process of repair increasingly is seen as a therapeutic target. In vitro models to study this process in primary intestinal cells are lacking.

Colonic CD90+ Crypt Fibroblasts Secrete Semaphorins to Support Epithelial Growth.

Intestinal epithelial cells have a defined hierarchy with stem cells located at the bottom of the crypt and differentiated cells more at the top. Epithelial cell renewal and differentiation are strictly controlled by various regulatory signals provided by epithelial as well as surrounding cells. Although there is evidence that stromal cells contribute to the intestinal stem cell niche, their markers and the soluble signals they produce have been incompletely defined.

Mouse fetal intestinal organoids: new model to study epithelial maturation from suckling to weaning.

During the suckling-to-weaning transition, the intestinal epithelium matures, allowing digestion of solid food. Transplantation experiments with rodent fetal epithelium into subcutaneous tissue of adult animals suggest that this transition is intrinsically programmed and occurs in the absence of dietary or hormonal signals. Here, we show that organoids derived from mouse primary fetal intestinal epithelial cells express markers of late fetal and neonatal development.

Heterozygosity of Chaperone Grp78 Reduces Intestinal Stem Cell Regeneration Potential and Protects against Adenoma Formation.

Deletion of endoplasmic reticulum resident chaperone Grp78 results in activation of the unfolded protein response and causes rapid depletion of the entire intestinal epithelium. Whether modest reduction of Grp78 may affect stem cell fate without compromising intestinal integrity remains unknown. Here, we employ a model of epithelial-specific, heterozygous deletion by use of mice and organoids.

Pivotal role of glutamine synthetase in ammonia detoxification.

Unlabelled: Glutamine synthetase (GS) catalyzes condensation of ammonia with glutamate to glutamine. Glutamine serves, with alanine, as a major nontoxic interorgan ammonia carrier. Elimination of hepatic GS expression in mice causes only mild hyperammonemia and hypoglutaminemia but a pronounced decrease in the whole-body muscle-to-fat ratio with increased myostatin expression in muscle.

A protocol for lentiviral transduction and downstream analysis of intestinal organoids.

Intestinal crypt-villus structures termed organoids, can be kept in sustained culture three dimensionally when supplemented with the appropriate growth factors. Since organoids are highly similar to the original tissue in terms of homeostatic stem cell differentiation, cell polarity and presence of all terminally differentiated cell types known to the adult intestinal epithelium, they serve as an essential resource in experimental research on the epithelium. The possibility to express transgenes or interfering RNA using lentiviral or retroviral vectors in organoids has increased opportunities for functional analysis of the intestinal epithelium and intestinal stem cells, surpassing traditional mouse transgenics in speed and cost.

Stromal Indian hedgehog signaling is required for intestinal adenoma formation in mice.

Background & Aims: Indian hedgehog (IHH) is an epithelial-derived signal in the intestinal stroma, inducing factors that restrict epithelial proliferation and suppress activation of the immune system. In addition to these rapid effects of IHH signaling, IHH is required to maintain a stromal phenotype in which myofibroblasts and smooth muscle cells predominate. We investigated the role of IHH signaling during development of intestinal neoplasia in mice.

Interorgan coordination of the murine adaptive response to fasting.

Starvation elicits a complex adaptive response in an organism. No information on transcriptional regulation of metabolic adaptations is available. We, therefore, studied the gene expression profiles of brain, small intestine, kidney, liver, and skeletal muscle in mice that were subjected to 0-72 h of fasting.

Glutamine synthetase deficiency in murine astrocytes results in neonatal death.

Glutamine synthetase (GS) is a key enzyme in the "glutamine-glutamate cycle" between astrocytes and neurons, but its function in vivo was thus far tested only pharmacologically. Crossing GS(fl/lacZ) or GS(fl/fl) mice with hGFAP-Cre mice resulted in prenatal excision of the GS(fl) allele in astrocytes. "GS-KO/A" mice were born without malformations, did not suffer from seizures, had a suckling reflex, and did drink immediately after birth, but then gradually failed to feed and died on postnatal day 3.

Glutamine synthetase in muscle is required for glutamine production during fasting and extrahepatic ammonia detoxification.

The main endogenous source of glutamine is de novo synthesis in striated muscle via the enzyme glutamine synthetase (GS). The mice in which GS is selectively but completely eliminated from striated muscle with the Cre-loxP strategy (GS-KO/M mice) are, nevertheless, healthy and fertile. Compared with controls, the circulating concentration and net production of glutamine across the hindquarter were not different in fed GS-KO/M mice.

The human neonatal small intestine has the potential for arginine synthesis; developmental changes in the expression of arginine-synthesizing and -catabolizing enzymes.

Background: Milk contains too little arginine for normal growth, but its precursors proline and glutamine are abundant; the small intestine of rodents and piglets produces arginine from proline during the suckling period; and parenterally fed premature human neonates frequently suffer from hypoargininemia. These findings raise the question whether the neonatal human small intestine also expresses the enzymes that enable the synthesis of arginine from proline and/or glutamine. Carbamoylphosphate synthetase (CPS), ornithine aminotransferase (OAT), argininosuccinate synthetase (ASS), arginase-1 (ARG1), arginase-2 (ARG2), and nitric-oxide synthase (NOS) were visualized by semiquantitative immunohistochemistry in 89 small-intestinal specimens.

Expression of glutamine synthetase and carbamoylphosphate synthetase i in a bioartificial liver: markers for the development of zonation in vitro.

Background: Mechanisms underlying hepatic zonation are not completely elucidated. In vitro test systems may provide new insights into current hypotheses. In this study, zonally expressed proteins, i.

Fasting induces a biphasic adaptive metabolic response in murine small intestine.

Background: The gut is a major energy consumer, but a comprehensive overview of the adaptive response to fasting is lacking. Gene-expression profiling, pathway analysis, and immunohistochemistry were therefore carried out on mouse small intestine after 0, 12, 24, and 72 hours of fasting.

Results: Intestinal weight declined to 50% of control, but this loss of tissue mass was distributed proportionally among the gut's structural components, so that the microarrays' tissue base remained unaffected.

Glutamine synthetase is essential in early mouse embryogenesis.

Glutamine synthetase (GS) is expressed in a tissue-specific and developmentally controlled manner, and functions to remove ammonia or glutamate. Furthermore, it is the only enzyme that can synthesize glutamine de novo. Since congenital deficiency of GS has not been reported, we investigated its role in early development.

Expression of thyroid hormone receptors A and B in developing rat tissues; evidence for extensive posttranscriptional regulation.

The perinatal changes in the pattern of expression of the thyroid hormone receptor (TR) isoforms TRalpha (1) TRalpha (2), TRbeta (1), and TRbeta (2) were investigated using in situ hybridization and immunohistochemistry, and RT-PCR and western blotting as visualization and quantification techniques respectively. In liver, lung, and kidney, TRalpha mRNA was expressed in the stromal and TRbeta mRNA in the parenchymal component of the tissues. When compared with liver, TRalpha mRNA concentrations were tenfold higher in lung, kidney, and intestine, and 100-fold higher in brain, with TRalpha (2) mRNA concentrations exceeding those of TRalpha (1) 5-to 10-fold.