scholarly journals Glucose-dependent insulinotropic polypeptide-mediated signaling pathways enhance apical PepT1 expression in intestinal epithelial cells

2015 ◽  
Vol 308 (1) ◽  
pp. G56-G62 ◽  
Author(s):  
Steven D. Coon ◽  
Vazhaikkurichi M. Rajendran ◽  
John H. Schwartz ◽  
Satish K. Singh
Keyword(s):  
Epithelial Cells ◽  
Signaling Pathways ◽  
Intestinal Epithelial Cells ◽  
Cell Model ◽  
Intestinal Epithelial ◽  
Akt Inhibitor ◽  
Membrane Expression ◽  
Intracellular Ca ◽  
Glucagon Like Peptide 1 ◽  
Apical Membranes

We have shown recently that glucose-dependent insulinotropic polypeptide (GIP), but not glucagon-like peptide 1 (GLP-1) augments H+ peptide cotransporter (PepT1)-mediated peptide absorption in murine jejunum. While we observed that inhibiting cAMP production decreased this augmentation of PepT1 activity by GIP, it was unclear whether PKA and/or other regulators of cAMP signaling pathway(s) were involved. This study utilized tritiated glycyl-sarcosine [3H-glycyl-sarcosine (Gly-Sar), a relatively nonhydrolyzable dipeptide] uptake to measure PepT1 activity in CDX2-transfected IEC-6 (IEC-6/CDX2) cells, an absorptive intestinal epithelial cell model. Similar to our earlier observations with mouse jejunum, GIP but not GLP-1 augmented Gly-Sar uptake (control vs. +GIP: 154 ± 22 vs. 454 ± 39 pmol/mg protein; P < 0.001) in IEC-6/CDX2 cells. Rp-cAMP (a PKA inhibitor) and wortmannin [phosophoinositide-3-kinase (PI3K) inhibitor] pretreatment completely blocked, whereas neither calphostin C (a potent PKC inhibitor) nor BAPTA (an intracellular Ca2+ chelator) pretreatment affected the GIP-augmented Gly-Sar uptake in IEC-6/CDX2 cells. The downstream metabolites Epac (control vs. Epac agonist: 287 ± 22 vs. 711 ± 80 pmol/mg protein) and AKT (control vs. AKT inhibitor: 720 ± 50 vs. 75 ± 19 pmol/mg protein) were shown to be involved in GIP-augmented PepT1 activity as well. Western blot analyses revealed that both GIP and Epac agonist pretreatment enhance the PepT1 expression on the apical membranes, which is completely blocked by wortmannin in IEC-6/CDX2 cells. These observations demonstrate that both cAMP and PI3K signaling pathways augment GIP-induced peptide uptake through Epac and AKT-mediated pathways in intestinal epithelial cells, respectively. In addition, these observations also indicate that both Epac and AKT-mediated signaling pathways increase apical membrane expression of PepT1 in intestinal absorptive epithelial cells.

scholarly journals Citrus Peels Phenolic Derivatives Alleviate Benzo[α]pyrene-Induced Inflammatory Injury of Human Intestinal Epithelial Cells Through NLRP3 and AhR Signaling Pathways

2021 ◽  
Author(s):  
Zhuwei Liang ◽  
Huailing Wang ◽  
Dan Luo ◽  
Xiaoyu Liu ◽  
Jie Liu
Keyword(s):  
Epithelial Cells ◽  
Signaling Pathways ◽  
Intestinal Epithelial Cells ◽  
Cell Model ◽  
Intestinal Epithelial ◽  
Human Intestinal Epithelial Cells ◽  
Pathway Activation ◽  
Citrus Peels ◽  
A Cell ◽  
Phenolic Derivatives

Abstract Benzo[α]pyrene (BaP) is ubiquitous in foods, and possesses a fatal cytotoxicity. In current study, ten Citrus peels (Chenpi) phenolic derivatives (CPDs) were isolated in a cell model of human intestinal epithelial (Caco-2) cells under BaP-exposure by a bio-assay guided method. Among them, methyl (3,4,5-trimethoxybenzoyl) valylphenylalaninate (Citrus peels phenolic derivative-2, CPD-2) performed the most protective activity by promoting the antiinflammatory potential on BaP-induced Caco-2 cells. CPD-2 inhibited BaP-induced intracellular ROS over-production and inflammatory epithelial cytokine, IL-4, IL-8, TNF-α, IL-1β and IL-18 over-expression, but not IL-6. CPD-2 also inhibited BaP-induced NLRP3 inflammasome and AhR signaling pathway activation. Overall, CPD-2 attenuates BaP-induced apoptotic death via promoting the antiinflammatory potentials by inhibiting the NLRP3 and AhR signaling pathways activation of Caco-2 cells. Finally, the Citrus peels phenolic derivatives was observed for the first time against BaP-induced inflammation and oxidative stress in human intestinal epithelial cells.

scholarly journals Type III Interferon Restriction by Porcine Epidemic Diarrhea Virus and the Role of Viral Protein nsp1 in IRF1 Signaling

2017 ◽  
pp. JVI.01677-17 ◽  
Author(s):  
Qingzhan Zhang ◽  
Hanzhong Ke ◽  
Anthony Blikslager ◽  
Takashi Fujita ◽  
Dongwan Yoo
Keyword(s):  
Epithelial Cells ◽  
Porcine Epidemic Diarrhea Virus ◽  
Nuclear Translocation ◽  
Intestinal Epithelial Cells ◽  
Cell Model ◽  
Intestinal Epithelial ◽  
Diarrhea Virus ◽  
Type Iii ◽  
Porcine Epidemic Diarrhea ◽  
Type Iii Ifn

Type III interferons (IFN-λs) play a vital role to maintain the antiviral state of the mucosal epithelial surface in the gut, and in turn, enteric viruses may have evolved to evade the type III IFN responses during infection. To study of the possible immune evasion of porcine epidemic diarrhea virus (PEDV) from type III IFN response, a line of porcine intestinal epithelial cells was developed as a cell model for PEDV replication. IFN-λ1 and IFN-λ3 inhibited the PEDV replication, indicating the anti-PEDV activity of type III IFNs. Of the 21 PEDV proteins, nsp1, nsp3, nsp5, nsp8, nsp14, nsp15, nsp16, ORF3, E, M, and N were found to suppress the type III IFN activities, and the IRF1 signaling mediated the suppression. PEDV specifically inhibited IRF1 nuclear translocation. Peroxisome is the innate antiviral signaling platform for activation of IRF1-mediated IFN-λ production, and peroxisomes were found to decrease in number in PEDV-infected cells. PEDV nsp1 blocked the nuclear translocation of IRF1 and reduced the number of peroxisomes to suppress IRF1-mediated type III IFNs. Mutational studies showed the conserved residues of nsp1 were crucial for IRF1-mediated IFN-λ suppression. Our study for the first time provides the evidence that the porcine enteric virus PEDV downregulates and evades the IRF1-mediated type III IFN responses by reducing the peroxisomes.IMPORTANCEPorcine epidemic diarrhea virus (PEDV) is a highly contagious enteric coronavirus emerged in swine in the US and has caused severe economic losses. PEDV targets the intestinal epithelial cells in the gut, and intestinal epithelial cells selectively induce and respond to the production of type III interferons (IFNs). However, little is known about modulation of type III IFN response by PEDV in the intestinal epithelial cells. In this study, we established a porcine intestinal epithelial cell model for PEDV replication. We found that PEDV inhibited the IRF1-mediated type III IFN production by decreasing the peroxisomes in number in the porcine intestinal epithelial cells. We also demonstrated that the conserved residues in the PEDV nsp1 protein were crucial for IFN suppression. This study for the first time showed the PEDV evasion of type III IFN response in the intestinal epithelial cells. It provides valuable information on the host cell-virus interactions not only for PEDV but also other enteric viral infections in swine.

252 Crosstalk Between PKD1 and β-Catenin Signaling Pathways in PKD1 Transgenic Mice and Cultures of Intestinal Epithelial Cells

2015 ◽  
Vol 148 (4) ◽  
pp. S-57
Author(s):  
James Sinnett-Smith ◽  
Yang Ni ◽  
Nora Rozengurt ◽  
Steven H. Young ◽  
Enrique Rozengurt
Keyword(s):  
Epithelial Cells ◽  
Transgenic Mice ◽  
Signaling Pathways ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial

IL-1 activates two phospholipid signaling pathways in intestinal epithelial cells

2001 ◽  
Vol 50 (7) ◽  
pp. 375-381 ◽  
Author(s):  
F. R. Homaidan ◽  
I. Chakroun ◽  
G. S. Dbaibo ◽  
W. El-Assaad ◽  
M. E. El-Sabban
Keyword(s):  
Epithelial Cells ◽  
Signaling Pathways ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Phospholipid Signaling

scholarly journals Gastrin Stimulates Cyclooxygenase-2 Expression in Intestinal Epithelial Cells through Multiple Signaling Pathways

2002 ◽  
Vol 277 (50) ◽  
pp. 48755-48763 ◽  
Author(s):  
Yan-Shi Guo ◽  
Ji-Zhong Cheng ◽  
Gui-Fang Jin ◽  
J. Silvio Gutkind ◽  
Mark R. Hellmich ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Signaling Pathways ◽  
Intestinal Epithelial Cells ◽  
Cyclooxygenase 2 ◽  
Intestinal Epithelial ◽  
Multiple Signaling

DUSP16 IS A NOVEL IBD GENE IMPLICATED IN THE REGULATION OF DIFFERENTIATION AND HOMEOSTASIS OF INTESTINAL EPITHELIAL CELLS

2021 ◽  
Vol 27 (Supplement_1) ◽  
pp. S29-S30
Author(s):  
Jessy Ntunzwenimana ◽  
Azadeh Alikashani ◽  
Claudine Beauchamp ◽  
Jean Paquette ◽  
Gabrielle Boucher ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Map Kinases ◽  
Intestinal Epithelial Cells ◽  
Cell Model ◽  
Basolateral Membrane ◽  
Intestinal Lumen ◽  
Interleukin 17 ◽  
Intestinal Epithelial ◽  
Intestinal Pathogens ◽  
Ht 29

Abstract Inflammatory bowel disease (IBD) are chronic inflammatory diseases including Crohn’s disease (CD) and ulcerative colitis (UC). More than 200 genomic regions have been identified and validated (association values〈 5x10-8) to be associated with CD, UC or IBD. These regions may contain multiple genes and the current challenge lies in identifying the causal gene in each of these. To address this problem, we performed a functional genomic screen of 145 genes from validated IBD loci, in a relevant intestinal epithelial cell model (HT-29). The results of this transcriptome-based screening revealed that the candidate IBD gene DUSP16 (a dual specificity phosphatase targeting MAP kinases (MAPKs) phosphorylation) as well as the known IBD gene KSR1 (a scaffold protein regulating the spatiotemporal activation of the ERK) regulate the expression of genes involved in intestinal differentiation and homeostasis. They induce, among others, the expression of the PIGR gene that encodes the polymeric immunoglobulin receptor. PIGR plays a role in transporting dimeric IgA molecules from the basolateral membrane of epithelial cells to the intestinal lumen, via transcytosis, where they play an essential role in protecting the epithelium against intestinal pathogens. Our hypothesis is that DUSP16 and KSR1 modulate the activity of MAPKs in intestinal epithelial cells to induce PIGR expression, thus participating in the maintenance of homeostasis of the intestinal barrier. To better understand how DUSP16 modulates the expression of PIGR, we used an approach of over- expression (cDNA) and knockdown (shRNA) of DUSP16 in HT-29 cells. Our results confirmed that DUSP16 induction increases the expression of PIGR, whereas a knockdown of DUSP16 reduces the basal level of PIGR. Next we confirmed by Western Blot that the induction of DUSP16 was accompanied by a decrease in MAPK phosphorylation. The involvement of MAPKs was also confirmed through the use of chemical inhibitors specific for each MAPK, with inhibition of ERK and p38 showing the strongest induction of PIGR expression. We are currently analyzing known functional mutants of DUSP16 and KSR1 to determine their impact on MAPK activity and on PIGR expression. This work supports a role for PIGR in disease pathogenesis, adding to two recent studies that documented that patients suffering from UC accumulated somatic mutations in a group of genes regulating the expression of PIGR by Interleukin 17. The mutated genes, including PIGR, were positively selected in inflamed tissues, indicating the importance of the biological function occupied by this gene in the maintenance of homeostasis. In conclusion, our study successfully identified functional links between two genes from independent IBD loci, and suggests that these DUSP16 and KSR1 play a role in the process of epithelial transcytosis and the development of IBD.

Sign in / Sign up

Export Citation Format

Share Document