Polyamine depletion is associated with an increase in JunD/AP-1 activity in small intestinal crypt cells

1999 ◽  
Vol 276 (2) ◽  
pp. G441-G450 ◽  
Author(s):  
Anami R. Patel ◽  
Jian-Ying Wang
Keyword(s):  
Cell Growth ◽  
Specific Inhibitor ◽  
Cell Types ◽  
Binding Activity ◽  
Activator Protein 1 ◽  
Intestinal Crypt ◽  
Regulate Cell Growth ◽  
Small Intestinal ◽  
Crypt Cells ◽  
Dialyzed Serum

Activator protein 1 (AP-1) is a group of dimeric transcription factors composed of protooncogene (Jun and Fos) subunits that bind to a common DNA site, the AP-1 binding site. The proteins of c-Jun, JunB, and Fos are essential for initiation of the cell cycle. Conversely, the activation of the junD gene slows cell growth in some cell types. The current study tests the hypothesis that polyamines influence cell growth by altering the balance of positive and negative Jun/AP-1 activities in intestinal epithelial cells. Studies were conducted in the IEC-6 cell line derived from rat small intestinal crypt cells. Administration of α-difluoromethylornithine (DFMO), a specific inhibitor for polyamine synthesis, for 4 and 6 days completely depleted cellular polyamine levels, while AP-1 binding activity was significantly increased. Spermidine, when given together with DFMO, restored AP-1 binding activity toward normal. The increased AP-1 complexes in polyamine-deficient cells were dramatically supershifted by the anti-JunD antibody but not by antibodies against c-Jun, JunB, or Fos proteins. There were significant increases in JunD mRNA and protein in DFMO-treated cells, although expression of the c- fos, c- jun, and junB genes decreased. The increase in JunD/AP-1 activity in DFMO-treated cells was associated with a significant decrease in cell division. Exposure of control quiescent cells to 5% dialyzed serum increased c-Jun/AP-1 but not JunD/AP-1 activities. DFMO prevented the stimulation of c-Jun/AP-1 activity induced by 5% dialyzed serum. These results indicate that 1) polyamine depletion is associated with an increase in AP-1 binding activity and 2) the increase in AP-1 activity in the DFMO-treated cells was primarily contributed by an increase in the JunD/AP-1. These findings suggest that polyamines regulate cell growth at least partially by modulating the balance of positive and negative Jun/AP-1 activities in the intestinal mucosa.

scholarly journals A novel marker glycoprotein for the microvillus membrane of surface colonocytes of rat large intestine and its presence in small-intestinal crypt cells.

1988 ◽  
Vol 106 (6) ◽  
pp. 1937-1946 ◽  
Author(s):  
S U Gorr ◽  
B Stieger ◽  
J A Fransen ◽  
M Kedinger ◽  
A Marxer ◽  
...  
Keyword(s):  
Small Intestine ◽  
Light And Electron Microscopy ◽  
Extraction Procedure ◽  
Distal Colon ◽  
Adult Rats ◽  
Intestinal Crypt ◽  
Phase Partitioning ◽  
Microvillus Membrane ◽  
Small Intestinal ◽  
Crypt Cells

Murine mAbs were produced against purified microvillus membranes of rat colonocytes in order to establish a marker protein for this membrane. The majority of antibodies binding to the colonic microvillus membrane recognized a single protein with a mean apparent Mr of 120 kD in both proximal and distal colon samples. The antigen is membrane bound as probed by phase-partitioning studies using Triton X-114 and by the sodium carbonate extraction procedure and is extensively glycosylated as assessed by endoglycosidase F digestion. Localization studies in adult rats by light and electron microscopy revealed the microvillus membrane of surface colonocytes as the principal site of the immunoreaction. The antigen was not detectable in kidney or liver by immunoprecipitation but was present in the small intestine, where it was predominantly confined to the apical membrane of crypt cells and much less to the microvillus membrane of differentiated enterocytes. During fetal development, the antigen appears first in the colon at day 15 and 1-2 d later in the small intestine. In both segments, it initially covers the whole luminal surface but an adult-like localization pattern develops soon after birth. The antibodies were also used to develop a radiometric assay for the quantification of the antigen in subcellular fractions of colonocytes in order to assess the validity of a previously developed method for the purification of colonic brush-border membranes (Stieger, B., A. Marxer, and H.P. Hauri. 1986. J. Membr. Biol. 91:19-31.). The results suggest that we have identified a valuable marker glycoprotein for the colonic microvillus membrane, which in adult rats may also serve as a marker for early differentiation of enterocyte progenitor cells in small-intestinal crypt cells.

Myc and Max disassociate following polyamine depletion in small intestinal crypt cells

1998 ◽  
Vol 114 ◽  
pp. A891
Author(s):  
J. Li ◽  
L. Li ◽  
JN. Rao ◽  
BL. Bass ◽  
J-Y. Wang
Keyword(s):  
Intestinal Crypt ◽  
Small Intestinal ◽  
Crypt Cells

Polyamines negatively regulate posttranscription of the P53 gene in small intestinal crypt cells

1998 ◽  
Vol 114 ◽  
pp. A431
Author(s):  
J.-Y. Wang ◽  
J. Li ◽  
AR. Patel ◽  
L. Li ◽  
JN. Rao
Keyword(s):  
P53 Gene ◽  
Intestinal Crypt ◽  
Small Intestinal ◽  
Crypt Cells

Loss of Rhb1, a Rheb-Related GTPase in Fission Yeast, Causes Growth Arrest With a Terminal Phenotype Similar to That Caused by Nitrogen Starvation

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 611-622 ◽  
Author(s):  
Kathleen E Mach ◽  
Kyle A Furge ◽  
Charles F Albright
Keyword(s):  
Cell Growth ◽  
Fission Yeast ◽  
Nitrogen Starvation ◽  
Cell Types ◽  
Nitrogen Levels ◽  
Ral Gtpases ◽  
Regulate Cell Growth ◽  
Cell Growth And Differentiation ◽  
Alternative Responses ◽  
Mutant Phenotypes

Abstract The Rheb GTPase is most similar in primary sequence to the Ras, Rap, R-Ras, and Ral GTPases, which regulate cell growth and differentiation in many cell types. A likely fission yeast homologue of mammalian Rheb, which we designated Rhb1, was identified by genome sequencing. Our investigation of rhb1 showed that rhb1− cells arrested cell growth and division with a terminal phenotype similar to that of nitrogenstarved cells. In particular, cells depleted of Rhb1 arrested as small, round cells with 1N DNA content, arrested more quickly in low-nitrogen medium, and induced expression of fnx1 and mei2 mRNA, two mRNAs that were normally induced by nitrogen starvation. Since mammalian Rheb binds and may regulate Raf-1, a Ras effector, we tested for functional overlap between Ras1 and Rhb1 in fission yeast. This analysis showed that Ras1 overexpression did not suppress rhb1− mutant phenotypes, Rhb1 overexpression did not suppress ras1− mutant phenotypes, and ras1−  rhb1− double mutants had phenotypes equal to the sum of the corresponding single-mutant phenotypes. Hence, there is no evidence for overlapping functions between Ras1 and Rhb1. On the basis of this study, we hypothesize that Rhb1 negatively regulates entry into stationary phase when extracellular nitrogen levels are adequate for growth. If this hypothesis is correct, then Rhb1 and Ras1 regulate alternative responses to limiting nutrients.

scholarly journals Co-localization of the Mammalian Hemochromatosis Gene Product (HFE) and a Newly Identified Transferrin Receptor (TfR2) in Intestinal Tissue and Cells

2003 ◽  
Vol 51 (5) ◽  
pp. 613-623 ◽  
Author(s):  
William J.H. Griffiths ◽  
Timothy M. Cox
Keyword(s):  
Transferrin Receptor ◽  
Iron Homeostasis ◽  
Receptor Gene ◽  
Hfe Gene ◽  
Transport Pathway ◽  
Intestinal Crypt ◽  
Hemochromatosis Gene ◽  
Small Intestinal ◽  
Potential Interactions ◽  
Crypt Cells

Mutations in the HFE gene and a newly identified second transferrin receptor gene, TfR2, cause hemochromatosis. The cognate proteins, HFE and TfR2, are therefore of key importance in human iron homeostasis. HFE is expressed in small intestinal crypt cells where transferrin-iron entry may determine subsequent iron absorption by mature enterocytes, but the physiological function of TfR2 is unknown. Using specific peptide antisera, we examined the duodenal localization of HFE and TfR2 in humans and mice, with and without HFE deficiency, by confocal microscopy. We also investigated potential interactions of these proteins in human intestinal cells in situ. Duodenal expression of HFE and TfR2 (but not TfR1) in wild-type mice and humans was restricted to crypt cells, in which they co-localized. HFE deficiency disrupted this interaction, altering the cellular distribution of TfR2 in human crypts. In human Caco-2 cells, HFE and TfR2 co-localized to a distinct CD63-negative vesicular compartment showing marked signal enhancement on exposure to iron-saturated transferrin ligand, indicating that HFE preferentially interacts with TfR2 in a specialized early endosomal transport pathway for transferrin-iron. This interaction occurs specifically in small intestinal crypt cells that differentiate to become iron-absorbing enterocytes. Our immunohistochemical findings provide evidence for a novel mechanism for the regulation of iron balance in mammals.

scholarly journals Cell Proliferation, Reactive Oxygen and Cellular Glutathione

Dose-Response ◽  
2005 ◽  
Vol 3 (3) ◽  
pp. dose-response.0 ◽  
Author(s):  
Regina M. Day ◽  
Yuichiro J. Suzuki
Keyword(s):  
Signal Transduction ◽  
Cell Growth ◽  
Cellular Proliferation ◽  
Reactive Oxygen ◽  
Cell Types ◽  
Antioxidant Response ◽  
Redox Status ◽  
Binding Activity ◽  
Hormetic Effect ◽  
Low Levels

A variety of cellular activities, including metabolism, growth, and death, are regulated and modulated by the redox status of the environment. A biphasic effect has been demonstrated on cellular proliferation with reactive oxygen species (ROS)—especially hydrogen peroxide and superoxide—in which low levels (usually submicromolar concentrations) induce growth but higher concentrations (usually >10–30 micromolar) induce apoptosis or necrosis. This phenomenon has been demonstrated for primary, immortalized and transformed cell types. However, the mechanism of the proliferative response to low levels of ROS is not well understood. Much of the work examining the signal transduction by ROS, including H2O2, has been performed using doses in the lethal range. Although use of higher ROS doses have allowed the identification of important signal transduction pathways, these pathways may be activated by cells only in association with ROS-induced apoptosis and necrosis, and may not utilize the same pathways activated by lower doses of ROS associated with increased cell growth. Recent data has shown that low levels of exogenous H2O2 up-regulate intracellular glutathione and activate the DNA binding activity toward antioxidant response element. The modulation of the cellular redox environment, through the regulation of cellular glutathione levels, may be a part of the hormetic effect shown by ROS on cell growth.

Identification of a 5-hydroxytryptamine (5-HT2) receptor on guinea pig small intestinal crypt cells

1993 ◽  
Vol 265 (2) ◽  
pp. G339-G346 ◽  
Author(s):  
A. K. Siriwardena ◽  
E. H. Smith ◽  
E. H. Borum ◽  
J. M. Kellum
Keyword(s):  
Guinea Pig ◽  
Dependent Manner ◽  
Maximal Inhibition ◽  
Concentration Dependent Manner ◽  
Intestinal Crypt ◽  
Mucosal Cells ◽  
Number Of Binding Sites ◽  
Small Intestinal ◽  
Ics 205 930 ◽  
Crypt Cells

Radioligand labeling of [3H]ketanserin was examined in suspensions of dispersed guinea pig small intestinal mucosal cells prepared by modification of the EDTA-chelation method described by M. M. Weiser (J. Biol. Chem. 248: 2536-2541, 1973). Preferential incorporation of [3H]thymidine was used to confirm that suspensions were enriched in crypt cells. At 25 degrees C, binding of [3H]ketanserin to dispersed enterocytes was rapid, maximal by 5 min, saturable (dissociation constant = 1.5 nM), 65 +/- 5% specific, stable, and reversible. The maximal number of binding sites per cell was 92,000 (range 86,000-105,500). Binding was temperature dependent, with maximal binding at 37 degrees C, and was inhibited by 5-hydroxytryptamine (5-HT) (half-maximal inhibition of [3H]ketanserin binding observed in response to 1 microM 5-HT) and ketanserin (half-maximal inhibition of [3H]ketanserin binding observed in response to 1 nM ketanserin) but not by the 5-HT1P antagonist N-acetyl-5-hydroxytryptophyl 5-hydroxytryptophan amide (5-HTP-DP) or the 5-HT3 antagonist 3-tropanyl-indole-3-carboxylate methiodide (ICS-205-930). The second messenger system coupled to the putative mucosal 5-HT2 receptor was examined. 5-HT stimulated a concentration-dependent production of inositol 1,4,5-trisphosphate (IP3) in the dispersed enterocytes. This was maximal at 1 min and was inhibited in a concentration-dependent manner by ketanserin. 5-HTP-DP and ICS-205-930 had no effect on 5-HT-stimulated production of IP3. These data provide evidence for the existence of a mucosal 5-HT2 receptor located on guinea pig small intestinal crypt cells.

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