scholarly journals Enhanced intestinal epithelial cell proliferation in diabetic rats correlates with β-catenin accumulation

2015 ◽  
Vol 226 (3) ◽  
pp. 135-143 ◽  
Author(s):  
Tatiana Dorfman ◽  
Yulia Pollak ◽  
Rima Sohotnik ◽  
Arnold G Coran ◽  
Jacob Bejar ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Real Time ◽  
Real Time Pcr ◽  
Intestinal Epithelial Cell ◽  
Diabetic Rats ◽  
Male Rats ◽  
Intestinal Cell ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation

The Wnt/β-catenin signaling cascade is implicated in the control of stem cell activity, cell proliferation, and cell survival of the gastrointestinal epithelium. Recent evidence indicates that the Wnt/β-catenin pathway is activated under diabetic conditions. The purpose of this study was to evaluate the role of Wnt/β-catenin signaling during diabetes-induced enteropathy in a rat model. Male rats were divided into three groups: control rats received injections of vehicle; diabetic rats received injections of one dose of streptozotocin (STZ); and diabetic–insulin rats received injections of STZ and were treated with insulin given subcutaneously at a dose of 1 U/kg twice daily. Rats were killed on day 7. Wnt/β-catenin-related genes and expression of proteins was determined using real-time PCR, western blotting, and immunohistochemistry. Among 13 genes identified by real-time PCR, seven genes were upregulated in diabetic rats compared with control animals including the target genes c-Myc and Tcf4. Diabetic rats also showed a significant increase in β-catenin protein compared with control animals. Treatment of diabetic rats attenuated the stimulating effect of diabetes on intestinal cell proliferation and Wnt/β-catenin signaling. In conclusion, enhanced intestinal epithelial cell proliferation in diabetic rats correlates with β-catenin accumulation.

scholarly journals Bile acids regulate intestinal cell proliferation by modulating EGFR and FXR signaling

2016 ◽  
Vol 310 (2) ◽  
pp. G81-G92 ◽  
Author(s):  
Avafia Y. Dossa ◽  
Oswaldo Escobar ◽  
Jamie Golden ◽  
Mark R. Frey ◽  
Henri R. Ford ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Bile Acids ◽  
Intestinal Epithelial Cell ◽  
Enteric Bacteria ◽  
Intestinal Cell ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation ◽  
Inhibition Of Proliferation ◽  
Genetic Ablation

Bile acids (BAs) are synthesized in the liver and secreted into the intestine. In the lumen, enteric bacteria metabolize BAs from conjugated, primary forms into more toxic unconjugated, secondary metabolites. Secondary BAs can be injurious to the intestine and may contribute to disease. The epidermal growth factor receptor (EGFR) and the nuclear farnesoid X receptor (FXR) are known to interact with BAs. In this study we examined the effects of BAs on intestinal epithelial cell proliferation and investigated the possible roles for EGFR and FXR in these effects. We report that taurine-conjugated cholic acid (TCA) induced proliferation, while its unconjugated secondary counterpart deoxycholic acid (DCA) inhibited proliferation. TCA stimulated phosphorylation of Src, EGFR, and ERK 1/2. Pharmacological blockade of any of these pathways or genetic ablation of EGFR abrogated TCA-stimulated proliferation. Interestingly, Src or EGFR inhibitors eliminated TCA-induced phosphorylation of both molecules, suggesting that their activation is interdependent. In contrast to TCA, DCA exposure diminished EGFR phosphorylation, and pharmacological or siRNA blockade of FXR abolished DCA-induced inhibition of proliferation. Taken together, these results suggest that TCA induces intestinal cell proliferation via Src, EGFR, and ERK activation. In contrast, DCA inhibits proliferation via an FXR-dependent mechanism that may include downstream inactivation of the EGFR/Src/ERK pathway. Since elevated secondary BA levels are the result of specific bacterial modification, this may provide a mechanism through which an altered microbiota contributes to normal or abnormal intestinal epithelial cell proliferation.

scholarly journals Isoflavones inhibit intestinal epithelial cell proliferation and induce apoptosis in vitro

1999 ◽  
Vol 80 (10) ◽  
pp. 1550-1557 ◽  
Author(s):  
C Booth ◽  
D F Hargreaves ◽  
J A Hadfield ◽  
A T McGown ◽  
C S Potten
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation

The influence of protein fractions from bovine colostrum digested in vivo and in vitro on human intestinal epithelial cell proliferation

2014 ◽  
Vol 81 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Alison J Morgan ◽  
Lisa G Riley ◽  
Paul A Sheehy ◽  
Peter C Wynn
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Proliferative Activity ◽  
Intestinal Epithelial Cell ◽  
Bovine Colostrum ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation ◽  
Human Intestinal Epithelial Cell

Colostrum consists of a number of biologically active proteins and peptides that influence physiological function and development of a neonate. The present study investigated the biological activity of peptides released from first day bovine colostrum through in vitro and in vivo enzymatic digestion. This was assessed for proliferative activity using a human intestinal epithelial cell line, T84. Digestion of the protein fraction of bovine colostrum in vitro was conducted with the enzymes pepsin, chymosin and trypsin. Pepsin and chymosin digests yielded protein fractions with proliferative activity similar to that observed with undigested colostrum and the positive control foetal calf serum (FCS). In contrast trypsin digestion significantly (P<0·05) decreased colostral proliferative activity when co-cultured with cells when compared with undigested colostrum. The proliferative activity of undigested colostrum protein and abomasal whey protein digesta significantly increased (P<0·05) epithelial cell proliferation in comparison to a synthetic peptide mix. Bovine colostrum protein digested in vivo was collected from different regions of the gastrointestinal tract (GIT) in newborn calves fed either once (n=3 calves) or three times at 12-h intervals (n=3 calves). Digesta collected from the distal duodenum, jejunum and colon of calves fed once, significantly (P<0·05) stimulated cell proliferation in comparison with comparable samples collected from calves fed multiple times. These peptide enriched fractions are likely to yield candidate peptides with potential application for gastrointestinal repair in mammalian species.

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