scholarly journals FOXA2 regulates a network of genes involved in critical functions of human intestinal epithelial cells

2015 ◽  
Vol 47 (7) ◽  
pp. 290-297 ◽  
Author(s):  
Nehal Gosalia ◽  
Rui Yang ◽  
Jenny L. Kerschner ◽  
Ann Harris
Keyword(s):  
Transcription Factors ◽  
Epithelial Cell ◽  
Binding Sites ◽  
Intestinal Epithelial Cell ◽  
Cell Function ◽  
Mrna Levels ◽  
Intestinal Epithelial ◽  
Membrane Function ◽  
Protein Levels ◽  
Genome Wide

The forkhead box A (FOXA) family of pioneer transcription factors is critical for the development of many endoderm-derived tissues. Their importance in regulating biological processes in the lung and liver is extensively characterized, though much less is known about their role in intestine. Here we investigate the contribution of FOXA2 to coordinating intestinal epithelial cell function using postconfluent Caco2 cells, differentiated into an enterocyte-like model. FOXA2 binding sites genome-wide were determined by ChIP-seq and direct targets of the factor were validated by ChIP-qPCR and siRNA-mediated depletion of FOXA1/2 followed by RT-qPCR. Peaks of FOXA2 occupancy were frequent at loci contributing to gene ontology pathways of regulation of cell migration, cell motion, and plasma membrane function. Depletion of both FOXA1 and FOXA2 led to a significant reduction in the expression of multiple transmembrane proteins including ion channels and transporters, which form a network that is essential for maintaining normal ion and solute transport. One of the targets was the adenosine A2B receptor, and reduced receptor mRNA levels were associated with a functional decrease in intracellular cyclic AMP. We also observed that 30% of FOXA2 binding sites contained a GATA motif and that FOXA1/A2 depletion reduced GATA-4, but not GATA-6 protein levels. These data show that FOXA2 plays a pivotal role in regulating intestinal epithelial cell function. Moreover, that the FOXA and GATA families of transcription factors may work cooperatively to regulate gene expression genome-wide in the intestinal epithelium.

scholarly journals Translocation of verotoxin-1 across T84 monolayers: mechanism of bacterial toxin penetration of epithelium

1997 ◽  
Vol 273 (6) ◽  
pp. G1349-G1358 ◽  
Author(s):  
Dana J. Philpott ◽  
Cameron A. Ackerley ◽  
Amanda J. Kiliaan ◽  
Mohamed A. Karmali ◽  
Mary H. Perdue ◽  
...  
Keyword(s):  
Epithelial Cell ◽  
Barrier Function ◽  
Pathogenic Bacteria ◽  
Intestinal Epithelial Cell ◽  
Cell Function ◽  
Bacterial Toxin ◽  
General Mechanism ◽  
Epithelial Cell Line ◽  
Intestinal Epithelial ◽  
T84 Cells

Verotoxin-producing Escherichia coli (VTEC) are pathogenic bacteria associated with diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Verotoxins (VTs) elaborated by these organisms produce cytopathic effects on a restricted number of cell types, including endothelial cells lining the microvasculature of the bowel and the kidney. Because human intestinal epithelial cells lack the globotriaosylceramide receptor for VT binding, it is unclear how the toxin moves across the intestinal mucosa to the systemic circulation. The aims of this study were to determine the effects of VT-1 on intestinal epithelial cell function and to characterize VT-1 translocation across monolayers of T84 cells, an intestinal epithelial cell line. VT-1 at concentrations up to 1 μg/ml had no effect on the barrier function of T84 monolayers as assessed by measuring transmonolayer electrical resistance (102 ± 8% of control monolayers). In contrast, both VT-positive and VT-negative VTEC bacterial strains lowered T84 transmonolayer resistance (45 ± 7 and 38 ± 6% of controls, respectively). Comparable amounts of toxin moved across monolayers of T84 cells, exhibiting high-resistance values, as monolayers with VTEC-induced decreases in barrier function, suggesting a transcellular mode of transport. Translocation of VT-1 across T84 monolayers paralleled the movement of a comparably sized protein, horseradish peroxidase. Immunoelectron microscopy confirmed transcellular transport of VT-1, since the toxin was observed within endosomes and associated with specific intracellular targets, including the Golgi network and endoplasmic reticulum. These data present a mode of VT-1 uptake by toxin-insensitive cells and suggest a general mechanism by which bacterial toxins lacking specific intestinal receptors can penetrate the intestinal epithelial barrier.

Activin a modulates intestinal epithelial cell function in vitro

2000 ◽  
Vol 32 ◽  
pp. A19
Author(s):  
S. Jung ◽  
K.M. Schulte ◽  
B. Wiedenmann ◽  
A.U. Dignass
Keyword(s):  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Cell Function ◽  
Activin A ◽  
Intestinal Epithelial

Lysophosphatidic Acid Modulates Intestinal Epithelial Cell Function in Vitro

1998 ◽  
Vol 859 (1 INTESTINAL PL) ◽  
pp. 223-226 ◽  
Author(s):  
ANDREAS STURM ◽  
ANDREA BECKER ◽  
KLAUS-MARTIN SCHULTE ◽  
HARALD GOEBELL ◽  
AXEL U. DIGNASS
Keyword(s):  
Epithelial Cell ◽  
Lysophosphatidic Acid ◽  
Intestinal Epithelial Cell ◽  
Cell Function ◽  
Intestinal Epithelial

scholarly journals Role of STAT6 and Mast Cells in IL-4- and IL-13-Induced Alterations in Murine Intestinal Epithelial Cell Function

2002 ◽  
Vol 169 (8) ◽  
pp. 4417-4422 ◽  
Author(s):  
Kathleen B. Madden ◽  
Lucia Whitman ◽  
Carolyn Sullivan ◽  
William C. Gause ◽  
Joseph F. Urban ◽  
...  
Keyword(s):  
Mast Cells ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Cell Function ◽  
Intestinal Epithelial

scholarly journals Tropomyosin distinguishes between the two actin-binding sites of villin and affects actin-binding properties of other brush border proteins.

1987 ◽  
Vol 104 (1) ◽  
pp. 29-40 ◽  
Author(s):  
D R Burgess ◽  
K O Broschat ◽  
J M Hayden
Keyword(s):  
Epithelial Cell ◽  
Protein Interactions ◽  
Brush Border ◽  
Binding Sites ◽  
Intestinal Epithelial Cell ◽  
Actin Binding ◽  
Intestinal Epithelial ◽  
Binding Properties ◽  
Order Of Magnitude ◽  
Protein Components

The intestinal epithelial cell brush border exhibits distinct localizations of the actin-binding protein components of its cytoskeleton. The protein interactions that dictate this subcellular organization are as yet unknown. We report here that tropomyosin, which is found in the rootlet but not in the microvillus core, can bind to and saturate the actin of isolated cores, and can cause the dissociation of up to 30% of the villin and fimbrin from the cores but does not affect actin binding by 110-kD calmodulin. Low speed sedimentation assays and ultrastructural analysis show that the tropomyosin-containing cores remain bundled, and that 110-kD calmodulin remains attached to the core filaments. The effects of tropomyosin on the binding and bundling activities of villin were subsequently determined by sedimentation assays. Villin binds to F-actin with an apparent Ka of 7 X 10(5) M-1 at approximate physiological ionic strength, which is an order of magnitude lower than that of intestinal epithelial cell tropomyosin. Binding of villin to F-actin presaturated with tropomyosin is inhibited relative to that to pure F-actin, although full saturation can be obtained by increasing the villin concentration. Villin also inhibits the binding of tropomyosin to F-actin, although not to the same extent. However, tropomyosin strongly inhibits bundling of F-actin by villin, and bundling is not recovered even at a saturating villin concentration. Since villin has two actin-binding sites, both of which are required for bundling, the fact that tropomyosin inhibits bundling of F-actin under conditions where actin is fully saturated with villin strongly suggests that tropomyosin's and one of villin's F-actin-binding sites overlap. These results indicate that villin and tropomyosin could compete for actin filaments in the intestinal epithelial cell, and that tropomyosin may play a major role in the regulation of microfilament structure in these and other cells.

Regulation of α1-antitrypsin gene expression in human intestinal epithelial cell line Caco-2 by HNF-1α and HNF-4

1999 ◽  
Vol 276 (5) ◽  
pp. G1181-G1194 ◽  
Author(s):  
Chaobin Hu ◽  
David H. Perlmutter
Keyword(s):  
Gene Expression ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Epithelial Cell Line ◽  
Mrna Levels ◽  
Intestinal Epithelial ◽  
Human Intestinal Epithelial Cell ◽  
Mobility Shift ◽  
Electrophoretic Mobility Shift Assays ◽  
Enterocyte Differentiation

There is still relatively limited information about mechanisms of gene expression in enterocytes and mechanisms by which gene expression is regulated during enterocyte differentiation. Using the human intestinal epithelial cell line Caco-2, which spontaneously differentiates from a cryptlike to a villouslike enterocyte, we have previously shown that there is a marked increase in transcription of the well-characterized α1-antitrypsin (α1-AT) gene during enterocyte differentiation. In this study we examined the possibility of identifying the cis-acting elements and trans-acting DNA-binding proteins responsible for expression of the α1-AT gene in Caco-2 cells during differentiation. Footprint analysis and electrophoretic mobility shift assays showed that hepatocyte nuclear factor-1α (HNF-1α), HNF-1β, and HNF-4 from nuclear extracts of Caco-2 cells specifically bound to two regions in the proximal promoter of the α1-AT gene. Cotransfection studies showed that HNF-1α and HNF-4 had a synergistic effect on α1-AT gene expression. RNA blot analysis showed that HNF-1α and HNF-4 mRNA levels and electrophoretic mobility shift assays showed that HNF-1α binding activity increase coordinately with α1-AT mRNA levels during differentiation of Caco-2 cells. Finally, overexpression of antisense ribozymes for HNF-1α in Caco-2 cells resulted in a selective decrease in endogenous α1-AT gene expression. Together, these results provide evidence that HNF-1α and HNF-4 play a role in the mechanism by which the α1-AT gene is upregulated during enterocyte differentiation in the model Caco-2 cell system.

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