The effects of glutamine on intestinal epithelial cell proliferation in parenterally fed rats.
Ontology highlight
ABSTRACT:
SUBMITTER: Mandir N
PROVIDER: S-EPMC1727517 | biostudies-other | 1999 May
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Myo-inositol is a breakdown product of phytate produced in the gut through the action of phytase. Although the effect of phytase-released phosphorus (P) on growth performance of animals has been well characterized, there is still little understanding of the effect of myo-inositol. The first objective of this study was to determine the effects of added myo-inositol to a phytate-rich low-protein diet on growth performance and apparent total tract digestibility (ATTD) in growing piglets. The second objective was to determine whether myo-inositol could directly affect intestinal epithelial cell proliferation and function for which we used intestinal porcine epithelial cells (IPEC-J2). A total of 128 weanling piglets were allotted to four dietary treatments consisting of eight replicates per treatment and four piglets per replicate in a randomized complete block design for 4 wk. The four experimental diets comprised the positive control [PC; 20% crude protein (CP)], negative control (NC; 17% CP), negative control plus 2.0g/kg myo-inositol (NC+INO; 17% CP), and negative control plus 3000FTU/kg phytase (NC+PHY; 17% CP). Average daily feed intake (ADFI), average daily gain (ADG), and gain-feed ratio (G: F) were recorded. Phytase supplementation in the protein-deficient NC diet increased the G:F ratio (P < 0.05) without myo-inositol effects on growth performance. Phosphorus digestibility in the phytase-supplemented group increased compared to the PC, NC, and NC+INO groups, whereas plasma myo-inositol concentration was significantly higher (P < 0.05) in the NC+INO group. Due to the lack of myo-inositol effect on growth performance, an additional in vitro study was conducted to determine the direct effect of myo-inositol on the intestinal epithelium that might not be reflected in growth performance. Myo-inositol increased the mRNA abundance of selected nutrient transporters in a concentration-dependent manner (P < 0.05). Myo-inositol also enhanced barrier integrity in the IPEC-J2 monolayer by increasing the transepithelial electrical resistance (TEER) with reduced paracellular permeability of FITC-dextran (P < 0.05). In conclusion, despite the lack of myo-inositol effect on animal performance, the in vitro data indicate that myo-inositol may directly regulate gut barrier integrity. Addition of myo-inositol to pig diets at levels that enhance intestinal epithelial cell function may result in effects on growth performance and gut health of pigs.
| S-EPMC9259597 | biostudies-literature
Project description:A metabolic transition from glycolysis to oxidative phosphorylation is often associated with differentiation of many types of stem cells. However, the link between mitochondrial respiration and stem cells' behavior is not fully understood. We genetically disrupted electron transport chain (ETC) complexes in the intestinal stem cells (ISCs) of Drosophila. We found that ISCs carrying impaired ETC proliferated much more slowly than normal and produced very few enteroblasts, which failed to further differentiate into enterocytes. One of the main impediments to ISC proliferation and lineage specification appeared to be abnormally elevated forkhead box O (FOXO) signaling in the ETC-deficient ISCs, as genetically suppressing the signaling pathway partially restored the number of enterocytes. Contrary to common belief, reactive oxygen species (ROS) accumulation did not appear to mediate the ETC mutant phenotype. Our results demonstrate that mitochondrial respiration is essential for Drosophila ISC proliferation and lineage specification in vivo and acts at least partially by repressing endogenous FOXO signaling.
| S-EPMC7359575 | biostudies-literature
Project description:Following damage to the intestinal epithelium, restoration of epithelial barrier integrity is triggered by a robust proliferative response. In other tissues, focal adhesion kinase (FAK) regulates many of the cellular processes that are critical for epithelial homeostasis and restitution, including cell migration, proliferation and survival. However, few studies to date have determined how FAK contributes to mucosal wound healing in vivo.To examine the role of FAK in intestinal epithelial homeostasis and during injury, we generated intestinal epithelium (IE)-specific conditional FAK knockout mice. Colitis was induced with dextran-sulfate-sodium (DSS) and intestinal tissues were analyzed by immunohistochemistry and immunoblotting. While intestinal development occurred normally in mice lacking FAK, FAK-deficient animals were profoundly susceptible to colitis. The loss of epithelial FAK resulted in elevated p53 expression and an increased sensitivity to apoptosis, coincident with a failure to upregulate epithelial cell proliferation. FAK has been reported to function as a mechanosensor, inducing cyclin D1 expression and promoting cell cycle progression under conditions in which tissue/matrix stiffness is increased. Collagen deposition, a hallmark of inflammatory injury resulting in increased tissue rigidity, was observed in control and FAK knockout mice during colitis. Despite this fibrotic response, the colonic epithelium in FAK-deficient mice exhibited significantly reduced cyclin D1 expression, suggesting that proliferation is uncoupled from fibrosis in the absence of FAK. In support of this hypothesis, proliferation of Caco-2 cells increased proportionally with matrix stiffness in vitro only under conditions of normal FAK expression; FAK depleted cells exhibited reduced proliferation concomitant with attenuated cyclin D1 expression.In the colon, FAK functions as a regulator of epithelial cell survival and proliferation under conditions of mucosal injury and a mechanosensor of tissue compliance, inducing repair-driven proliferation in the colonic epithelium through upregulation of cyclin D1.
| S-EPMC3160839 | biostudies-literature
Project description:BackgroundPreviously, we showed that M3 muscarinic receptor (M3R; gene name Chrm3) deficiency attenuates murine intestinal neoplasia, supporting the hypothesis that muscarinic receptors play an important role in intestinal tumorigenesis.MethodsTo test this hypothesis, in the present study we treated mice with bethanechol, a non-selective muscarinic receptor agonist without nicotinic receptor activity, and examined its effects on azoxymethane (AOM)-induced colon neoplasia. Mice were provided with drinking water containing 400 μg/mL bethanechol chloride or water without additions (control) for a total of 20 weeks, a period that included the initial 6 weeks when mice received intraperitoneal injections of AOM.ResultsWhen euthanized at week 20, control mice had 8.0 ± 1.3 tumors per animal, whereas bethanechol-treated mice had 10.4 ± 1.5 tumors per mouse (mean ± SE; P = 0.023), a 30% increase. Strikingly, tumor volume per animal was increased 52% in bethanechol-treated compared with control mice (179.7 ± 21.0 vs. 111. 8 ± 22.4 mm(3); P = 0.047). On histological examination, bethenechol-treated mice also had more adenocarcinomas per animal (8.0 ± 1.0 vs. 4.1 ± 0.6 for control mice, P = 0.0042). Cell proliferation in both normal mucosa and adenocarcinomas was increased in bethanechol-treated compared to control mice. Also, in tumors, bethanechol treatment increased expression of Chrm3, Egfr and post-Egfr signaling molecules Myc and cyclin D1. Bethanechol treatment increased the thickness of normal colonic mucosa and the expression of selected matrix metalloproteinase (Mmp) genes, including Mmp7, Mmp10 and Mmp13.ConclusionsThese findings support a prominent role for muscarinic receptors in colon neoplasia, and identify post-receptor signaling molecules as potential therapeutic targets.
| S-EPMC3640951 | biostudies-literature
Project description:The gut microbiota exerts a variety of positive effects on the intestinal homeostasis, including the production of beneficial molecules, control of the epithelial barrier integrity and the regulation of the balance between host's cell death and proliferation. The interactions between commensal bacteria and intestinal cells are still under-investigated and is then of paramount importance to address such interactions at the molecular and cellular levels. We report an in vitro analysis of the effects of molecules secreted by Lactobacillus gasseri SF1183 on HCT116 cells, selected as a model of intestinal epithelial cells. SF1183 is a L. gasseri strain isolated from an ileal biopsy of a human healthy volunteer, able to prevent colitis symptoms in vivo. Expanding previous findings, we show that bioactive molecules secreted by SF1183 reduce the proliferation of HCT116 cells in a reversible manner determining a variation in cell cycle markers (p21WAF, p53, cyclin D1) and resulting in the protection of HCT116 cells from TNF-alfa induced apoptosis, an effect potentially relevant for the protection of the epithelial barrier integrity and reconstitution of tissue homeostasis. Consistently, SF1183 secreted molecules increase the recruitment of occludin, a major component of TJ, at the cell-cell contacts, suggesting a reinforcement of the barrier function.
| S-EPMC9691729 | biostudies-literature
Project description:Alanyl-glutamine (Ala-Gln) has recently been shown to enhance catch-up growth and gut integrity in undernourished children from Northeast Brazil. We hypothesized that the intestinal epithelial effects of Ala-Gln in malnourished weanling mice and mouse small intestinal epithelial (MSIE) cells would include modulation of barrier function, proliferation, and apoptosis. Dams of 10-day-old suckling C57BL/6 pups were randomized to a standard diet or an isocaloric Northeast Brazil "regional basic diet," moderately deficient in protein, fat, and minerals. Upon weaning to their dam's diet on day of life 21, pups were randomized to Ala-Gln solution or water. At 6 wk of age, mice were killed, and jejunal tissue was collected for morphology, immunohistochemistry, and Ussing chamber analysis of transmucosal resistance and permeability. Proliferation of MSIE cells in the presence or absence of Ala-Gln was measured by MTS and bromodeoxyuridine assays. MSIE apoptosis was assessed by annexin and 7-amino-actinomycin D staining. Pups of regional basic diet-fed dams exhibited failure to thrive. Jejunal specimens from undernourished weanlings showed decreased villous height and crypt depth, decreased transmucosal resistance, increased permeability to FITC-dextran, increased claudin-3 expression, and decreased epithelial proliferation and increased epithelial apoptosis (as measured by bromodeoxyuridine and cleaved caspase-3 staining, respectively). Undernourished weanlings supplemented with Ala-Gln showed improvements in weight velocity, villous height, crypt depth, transmucosal resistance, and epithelial proliferation/apoptosis compared with unsupplemented controls. Similarly, Ala-Gln increased proliferation and reduced apoptosis in MSIE cells. In summary, Ala-Gln promotes intestinal epithelial homeostasis in a mouse model of malnutrition-associated enteropathy, mimicking key features of the human disease.
| S-EPMC3191556 | biostudies-literature
Project description:BackgroundThe hypocholesterolemic effects of lactic acid bacteria (LAB) have now become an area of great interest and controversy for many scientists. In this study, we evaluated the effects of Lactobacillus plantarum 9-41-A and Lactobacillus fermentum M1-16 on body weight, lipid metabolism and intestinal microflora of rats fed a high-cholesterol diet.MethodsForty rats were assigned to four groups and fed either a normal or a high-cholesterol diet. The LAB-treated groups received the high-cholesterol diet supplemented with Lactobacillus plantarum 9-41-A or Lactobacillus fermentum M1-16. The rats were sacrificed after a 6-week feeding period. Body weights, visceral organ and fat pad weights, serum and liver cholesterol and lipid levels, and fecal cholesterol and bile acid concentrations were measured. Liver lipid deposition and adipocyte size were evaluated histologically.ResultsCompared with rats fed a high-cholesterol diet but without LAB supplementation, serum total cholesterol, low-density lipoprotein cholesterol and triglycerides levels were significantly decreased in LAB-treated rats (p < 0.05), with no significant change in high-density lipoprotein cholesterol levels. Hepatic cholesterol and triglyceride levels and liver lipid deposition were significantly decreased in the LAB-treated groups (p < 0.05). Accordingly, both fecal cholesterol and bile acids levels were significantly increased after LAB administration (p < 0.05). Intestinal Lactobacillus and Bifidobacterium colonies were increased while Escherichia coli colonies were decreased in the LAB-treated groups. Fecal water content was higher in the LAB-treated groups. Compared with rats fed a high-cholesterol diet, administration of Lactobacillus plantarum 9-41-A resulted in decreases in the body weight gain, liver and fat pad weight, and adipocytes size (p < 0.05).ConclusionsThis study suggests that LAB supplementation has hypocholesterolemic effects in rats fed a high-cholesterol diet. The ability to lower serum cholesterol varies among LAB strains. Our strains might be able to improve the intestinal microbial balance and potentially improve intestinal transit time. Although the mechanism is largely unknown, L. plantarum 9-41-A may play a role in fat metabolism.
| S-EPMC3144010 | biostudies-literature
Project description:Cancer cells can use a variety of metabolic substrates to fulfill the bioenergetic and biosynthetic needs of their oncogenic program. Besides bioenergetics, cancer cell metabolism also directly influences genetic, epigenetic and signaling events associated with tumor progression. Many cancer cells are addicted to glutamine, and this addiction is observed in oxidative as well as in glycolytic cells. Although both oxidative and bioreductive glutamine metabolism can contribute to cancer progression and glutamine can further serve to generate peptides (including glutathione) and proteins, we report that glutamine promotes the proliferation of cancer cells independently of its use as a metabolic fuel or as a precursor of glutathione. Extracellular glutamine activates transcription factor signal transducer and activator of transcription 3 (STAT3), which is necessary and sufficient to mediate the proliferative effects of glutamine on glycolytic and oxidative cancer cells. Glutamine also activates transcription factors hypoxia-inducible factor-1, mammalian target of rapamycin and c-Myc, but these factors do not mediate the effects of glutamine on cancer cell proliferation. Our findings shed a new light on the anticancer effects of l-asparaginase that possesses glutaminase activity and converts glutamine into glutamate extracellularly. Conversely, cancer resistance to treatments that block glutamine metabolism could arise from glutamine-independent STAT3 reactivation.
| S-EPMC5245769 | biostudies-literature
Project description:Background & aimsGlutamine plays a protective role in intestinal cells during physiologic stress; however, the protection mechanisms are not fully understood. Autophagy functions in bulk degradation of cellular components, but has been recognized recently as an important mechanism for cell survival under conditions of stress. We therefore sought to see if glutamine's actions involve the induction of autophagy in intestinal cells and, if so, the mechanisms that underlie this action.MethodsFormation of microtubule-associated protein light chain 3 (LC3)-phospholipid conjugates (LC3-II) in rat intestinal epithelial IEC-18 cells and human colonic epithelial Caco-2(BBE) cells was determined by Western blotting and localized by confocal microscopy. Activation of mammalian target of rapamycin (mTOR) pathway, mitogen-activated protein (MAP) kinases, caspase-3, and poly (ADP-ribose) polymerase were monitored by Western blotting.ResultsGlutamine increased LC3-II as well as the number of autophagosomes. Glutamine-induced LC3-II formation was paralleled by inactivation of mTOR and p38 MAP kinase pathways, and inhibition of mTOR and p38 MAP kinase allowed LC3-II induction in glutamine-deprived cells. Under glutamine starvation, LC3-II recovery after heat stress or the increase under oxidative stress was blunted significantly. Glutamine depletion increased caspase-3 and poly (ADP-ribose) polymerase activity after heat stress, which was inhibited by treatment with inhibitors of mTOR and p38 MAP kinase.ConclusionsGlutamine induces autophagy under basal and stressed conditions, and prevents apoptosis under heat stress through its regulation of the mTOR and p38 MAP kinase pathways. We propose that glutamine contributes to cell survival during physiologic stress by induction of autophagy.
| S-EPMC2673957 | biostudies-literature
Project description:Background & aimsThe embryonic small intestinal epithelium is highly proliferative, and although much is known about mechanisms regulating proliferation in the adult intestine, the mechanisms controlling epithelial cell proliferation in the developing intestine are less clear. GATA4, a transcription factor that regulates proliferation in other developing tissues, is first expressed early in the developing gut in midgut endoderm. GATA4 function within midgut endoderm and the early intestinal epithelium has not been investigated.MethodsUsing Sonic Hedgehog Cre to eliminate GATA4 in the midgut endoderm of mouse embryos, we determined the impact of loss of GATA4 on intestinal development, including epithelial cell proliferation, between E9.5-E18.5.ResultsWe found that intestinal length and width were decreased in GATA4 mutants compared with controls. GATA4-deficient intestinal epithelium contained fewer cells, and epithelial girth was decreased. We further observed a decreased proportion of proliferating cells at E10.5 and E11.5 in GATA4 mutants. We demonstrated that GATA4 binds to chromatin containing GATA4 consensus binding sites within Cyclin D2 (Ccnd2), Cyclin dependent kinase 6 (Cdk6), and Frizzled 5 (Fzd5). Moreover, Ccnd2, Cdk6, and Fzd5 transcripts were reduced at E11.5 in GATA4 mutant tissue. Villus morphogenesis was delayed, and villus structure was abnormal in GATA4 mutant intestine.ConclusionsOur data identify GATA4 as an essential regulator of early intestinal epithelial cell proliferation. We propose that GATA4 controls proliferation in part by directly regulating transcription of cell cycle mediators. Our data further suggest that GATA4 affects proliferation through transcriptional regulation of Fzd5, perhaps by influencing the response of the epithelium to WNT signaling.
| S-EPMC4823006 | biostudies-literature