Digestion of tripeptides and disaccharides: relationship with brush border hydrolases

1976 ◽  
Vol 231 (1) ◽  
pp. 87-92 ◽  
Author(s):  
C Arvanitakis ◽  
J Ruhlen ◽  
J Folscroft ◽  
JB Rhodes
Keyword(s):  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Intestinal Epithelial ◽  
Cytoplasmic Fraction ◽  
Perfusion Studies ◽  
Intestinal Digestion ◽  
Microvillus Membrane ◽  
Hydrolysis Of ◽  
Glycyl Glycine

Intestinal digestion of two tripeptides (leucyl-glycyl-glycine, prolyl-glycyl-glycine) and two disacchrarides (sucrose, maltose) was examined in the hamster by intestinal perfusion in vivo and hydrolysis of the substrates by microvillus membranes. Perfusion studies showed that luminal disappearance rates of leucyl-glycl-glycine were significantly higher than prolyl-glycyl-glycine (P less than o.001), sucrose (P less than 0.001), and maltose (P less than 0.005). Hydrolytic products of leucyl-glycyl-glycine, sucrose, and maltose were detected in the gut lumen in appreciable concentrations, whereas negligible concentrations of prolyl-glycyl-glycine products were present. Leucyl-glycyl-glycine hydrolysis in microvillus membranes was markedly higher than prolyl-glycyl-glycine (P less than 0.001), which was predominant in the cytoplasmic fraction. These results indicate that leucyl-glycyl-glycine, like sucrose and maltose, is hydrolyzed at the membrane. With some tripeptides, i.e., leucyl-glycyl-glycine, digestion occurs at the microvillus membrane with subsequent transport of hydrolytic products into the intestinal epithelial cell. Other tripeptides, i.e., prolyl-glycyl-glycine, may cross the membrane and undergo intracellular hydrolysis by cytoplasmic peptidases.

Effects of lactoferrin on intestinal epithelial cell growth and differentiation: an in vivo and in vitro study

BioMetals ◽  
2014 ◽  
Vol 27 (5) ◽  
pp. 857-874 ◽  
Author(s):  
Anne Blais ◽  
Cuibai Fan ◽  
Thierry Voisin ◽  
Najat Aattouri ◽  
Michel Dubarry ◽  
...  
Keyword(s):  
Cell Growth ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
In Vitro Study ◽  
Vitro Study ◽  
Intestinal Epithelial ◽  
Cell Growth And Differentiation

scholarly journals Deficiency in the anti-apoptotic protein DJ-1 promotes intestinal epithelial cell apoptosis and aggravates inflammatory bowel disease via p53

2020 ◽  
Vol 295 (13) ◽  
pp. 4237-4251 ◽  
Author(s):  
Jie Zhang ◽  
Min Xu ◽  
Weihua Zhou ◽  
Dejian Li ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Inflammatory Bowel Disease ◽  
Epithelial Cell ◽  
Bowel Disease ◽  
Intestinal Epithelial Cell ◽  
Intestinal Inflammation ◽  
Intestinal Epithelial ◽  
P53 Expression ◽  
Inflammatory Bowel

Parkinson disease autosomal recessive, early onset 7 (PARK7 or DJ-1) is involved in multiple physiological processes and exerts anti-apoptotic effects on multiple cell types. Increased intestinal epithelial cell (IEC) apoptosis and excessive activation of the p53 signaling pathway is a hallmark of inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD). However, whether DJ-1 plays a role in colitis is unclear. To determine whether DJ-1 deficiency is involved in the p53 activation that results in IEC apoptosis in colitis, here we performed immunostaining, real-time PCR, and immunoblotting analyses to assess DJ-1 expression in human UC and CD samples. In the inflamed intestines of individuals with IBD, DJ-1 expression was decreased and negatively correlated with p53 expression. DJ-1 deficiency significantly aggravated colitis, evidenced by increased intestinal inflammation and exacerbated IEC apoptosis. Moreover, DJ-1 directly interacted with p53, and reduced DJ-1 levels increased p53 levels both in vivo and in vitro and were associated with decreased p53 degradation via the lysosomal pathway. We also induced experimental colitis with dextran sulfate sodium in mice and found that compared with DJ-1−/− mice, DJ-1−/−p53−/− mice have reduced apoptosis and inflammation and increased epithelial barrier integrity. Furthermore, pharmacological inhibition of p53 relieved inflammation in the DJ-1−/− mice. In conclusion, reduced DJ-1 expression promotes inflammation and IEC apoptosis via p53 in colitis, suggesting that the modulation of DJ-1 expression may be a potential therapeutic strategy for managing colitis.

scholarly journals Intestinal epithelial cell-specific IGF1 promotes the expansion of intestinal stem cells during epithelial regeneration and functions on the intestinal immune homeostasis

2018 ◽  
Vol 315 (4) ◽  
pp. E638-E649 ◽  
Author(s):  
Yu Zheng ◽  
Yongli Song ◽  
Qi Han ◽  
Wenjie Liu ◽  
Jiuzhi Xu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
High Throughput Sequencing ◽  
Secretory Cells ◽  
Intestinal Epithelial ◽  
Epithelial Stem Cells ◽  
Microbial Composition ◽  
Epithelial Regeneration

It is well known that insulin-like growth factor 1 (IGF1) acts as a trophic factor in small intestine under both physiological and pathophysiological conditions. However, it still lacks direct in vivo evidence of the functions of intestinal epithelial cell (IEC)-specific IGF1 under both normal and pathological conditions. Using IEC-specific IGF1-knockout (cKO) mice and Lgr5-eGFP-CreERT mice, we demonstrate that IEC-specific IGF1 can enhance nutrient uptake, reduce protein catabolism and energy consumption, and promote the proliferation and expansion of intestinal epithelial cells, including intestinal epithelial stem cells and intestinal secretory cells. Next, we showed that IEC-specific IGF1 renders IECs resistant to irradiation and promotes epithelial regeneration. Strikingly, transcriptome profiling assay revealed that many differentially expressed genes involved in the differentiation and maturation of lymphoid lineages were significantly suppressed in the cKO mice as compared with the control mice. We demonstrated that deletion of IGF1 in IECs enhances bacterial translocation to the mesenteric lymph nodes and liver. Furthermore, high-throughput sequencing of 16S ribosomal RNA genes of gut microbiota revealed that IEC-specific IGF1 loss profoundly affected the gut microbial composition at various levels of classification. Therefore, our findings shed light on the in vivo roles of IEC-specific IGF1 in intestinal homeostasis, epithelial regeneration, and immunity, broadening our current insights on IGF1 functions.

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.

scholarly journals Rapid protein kinase D1 signaling promotes migration of intestinal epithelial cells

2012 ◽  
Vol 303 (3) ◽  
pp. G356-G366 ◽  
Author(s):  
Steven H. Young ◽  
Nora Rozengurt ◽  
James Sinnett-Smith ◽  
Enrique Rozengurt
Keyword(s):  
Protein Kinase ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Intestinal Epithelial Cell ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Protein Kinase D1

We have examined the role of protein kinase D1 (PKD1) signaling in intestinal epithelial cell migration. Wounding monolayer cultures of intestinal epithelial cell line IEC-18 or IEC-6 induced rapid PKD1 activation in the cells immediately adjacent to the wound edge, as judged by immunofluorescence microscopy with an antibody that detects the phosphorylated state of PKD1 at Ser916, an autophosphorylation site. An increase in PKD1 phosphorylation at Ser916 was evident as early as 45 s after wounding, reached a maximum after 3 min, and persisted for ≥15 min. PKD1 autophosphorylation at Ser916 was prevented by the PKD family inhibitors kb NB 142-70 and CRT0066101. A kb NB 142-70-sensitive increase in PKD autophosphorylation was also elicited by wounding IEC-6 cells. Using in vitro kinase assays after PKD1 immunoprecipitation, we corroborated that wounding IEC-18 cells induced rapid PKD1 catalytic activation. Further results indicate that PKD1 signaling is required to promote migration of intestinal epithelial cells into the denuded area of the wound. Specifically, treatment with kb NB 142-70 or small interfering RNAs targeting PKD1 markedly reduced wound-induced migration in IEC-18 cells. To test whether PKD1 promotes migration of intestinal epithelial cells in vivo, we used transgenic mice that express elevated PKD1 protein in the small intestinal epithelium. Enterocyte migration was markedly increased in the PKD1 transgenic mice. These results demonstrate that PKD1 activation is one of the early events initiated by wounding a monolayer of intestinal epithelial cells and indicate that PKD1 signaling promotes the migration of these cells in vitro and in vivo.

14 COLONIC EPITHELIAL CELL-SPECIFIC AFTIPHILIN KNOCKDOWN REGULATES EPITHELIAL BARRIER FUNCTION THROUGH MYOSIN LIGHT CHAIN-ASSOCIATED ACTIN ORGANIZATION IN VITRO AND INTESTINAL LENGTH IN VIVO

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S28-S28
Author(s):  
Ivy Ka Man Law ◽  
Carl Rankin ◽  
Charalabos Pothoulakis
Keyword(s):  
Epithelial Cell ◽  
Barrier Function ◽  
Intestinal Epithelial Cell ◽  
Epithelial Barrier ◽  
Intestinal Epithelial ◽  
Knock Out ◽  
Epithelial Barrier Function ◽  
Actin Organization

Abstract Background and Aims Colonic epithelial integrity is often compromised during colonic inflammation and Inflammatory Bowel Disease. Aftiphilin (AFTPH) is a downstream target of microRNA-133a and its expression is reduced in colonic tissues of wild type mice from experimental colitis models and colonic biopsies from patients with ulcerative colitis. We have previously shown that AFTPH is involved in regulating intestinal epithelial barrier function and actin organization in human colonic epithelial cells in vitro (DDW 2016). On the other hand, our results suggested that global aftiphilin knock-out is embryonic lethal in mouse models (DDW 2019). Here, we further examined the role of AFTPH in regulating actin organization in vitro and characterize the colonic epithelial cell-specific aftiphilin knock-out mice. Methods Human colonic epithelial NCM460 cells were transfected with si-RNA against AFTPH to achieve transient AFTPH gene-silencing. Stable AFTPH knock-down clones were generated by transducing Caco2-BBE cells with recombinant lentivirus carrying sh-AFTPH or control sh-RNA. To create intestinal epithelial cell-specific aftiphilin knock-out mice, Aftph flox/flox mice were cross-bred with B6.Cg-Tg(Vil1-cre)997Gum/J mice, which express Villin-driven Cre recombinase (Vil-Cre), to generate intestinal epithelial cell-specific aftiphilin knock-out mice (Aftph Vil-/Vil-). Protein expression of F- and G-actin and p70S6K were detected using Western blot. Tissues from various organs were collected with Aftph Vil-/Vil- and its wildtype counterparts at 12 weeks. Results Results from western blot analysis showed that F-/G-actin ratio in AFTPH gene-silenced NCM460 cells were 0.6±0.17 fold, when compared to the treatment control. In addition, AFTPH gene-silencing in human colonic epithelial cells activated p70S6K, a kinase that is involved in actin organization, when compared to treatment control (1.2±0.15 vs. 2.0±0.15, p=0.0354). Furthermore, transepithelial electric resistance (TER) of Caco2-BBE cells deficient in AFTPH is significantly lower than that of control cells (0.5±0.07 fold). Lastly, in vivo intestinal epithelial cell-specific Aftph knock-out increased the length of small intestine, when compared to that of wild type mice (30.7±0.33 vs. 34.8±0.97, p=0.02), while the tissue weight of spleen to body weight was reduced (0.30±0.011 vs. 0.26±0.006, p=0.0169). Summary and Conclusions Our results indicate that AFTPH directly regulates epithelial barrier function and actin organization through mediating F-/G-actin ratio in human colonic epithelial cells, possibly through p70S6K. Importantly, intestinal epithelial cell-specific knock-out in vivo increased intestinal length and reduced size of the spleen. Our results suggested that AFTPH is crucial in regulating colonic epithelial barrier function in vitro and intestinal homeostasis.

scholarly journals Immunohistochemical and biochemical demonstration of the change in glycolipid composition of the intestinal epithelial cell surface in mice in relation to epithelial cell differentiation and bacterial association.

1984 ◽  
Vol 32 (3) ◽  
pp. 299-304 ◽  
Author(s):  
Y Umesaki
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Intestinal Epithelial Cell ◽  
Small Intestinal Mucosa ◽  
Intestinal Epithelial ◽  
Germ Free ◽  
Microvillus Membrane ◽  
Small Intestinal ◽  
Asialo Gm1 ◽  
Crypt Cells

We have previously demonstrated the appearance of fucosyl asialo-GM1 (FGA1) in the small-intestinal epithelial cells of germ-free mice via the induction of GDP-fucose: asialo-GM1 (GA1) alpha(1 leads to 2) fucosyltransferase (FT) after the conventionalization of these animals (Umesaki Y, Sakata T, Yajima T: Biochem Biophys Res Commun 105:439, 1982). The present study, based on this earlier work, demonstrates the changes in the glycolipid antigens of the small-intestinal epithelial-cell membrane as shown immunohistochemically with specific antibodies raised against asialo GM1 (GA1) and FGA1. In germ-free mice, GA1 was localized both in the villus cells and in the crypt cells. In the process of conventionalization, FGA1 appeared in the villus cells while the GA1 content of these cells was decreased. Four to 5 days after the conventionalization procedure, the fluorescence produced by anti-FGA1 was strongest in the villus cells, while that produced by anti-GA1 was detected only in the crypt cells. At this same time the FT activity of the small-intestinal mucosa was highest, with most of the GA1 apparently being converted into FGA1, as shown in the paper cited above. Thereafter, the GA1 content of both the villus and crypt cells again increased greatly. On the other hand, the fluorescence produced with anti-FGA1 decreased, and could no longer be detected 14 days after conventionalization. The activity of FT, measured biochemically in epithelial cells differentially isolated from the villus tip to the crypt, was greater in the villus than in the crypt region. This confirmed the intense staining with anti-FGA1 that was seen in villus cells. The fluorescence produced by the two anti-glycolipid antibodies used in the study distributed not only in the microvillus membrane but also to some extent in the basolateral membrane. The localization of the respective glycolipids contrasted with that of the glycoprotein sucrase--isomaltase enzyme complex, the fluorescence of which was exclusively confined to the microvillus-membrane side of the villus cells.

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