Sp1 and Sp3 mediate NHE2 gene transcription in the intestinal epithelial cells

2007 ◽  
Vol 293 (1) ◽  
pp. G146-G153 ◽  
Author(s):  
Ping Hua ◽  
Hua Xu ◽  
Jennifer K. Uno ◽  
Maciej A. Lipko ◽  
Jiali Dong ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Epithelial Cells ◽  
Gene Transcription ◽  
Promoter Region ◽  
Promoter Activity ◽  
Intestinal Epithelial Cells ◽  
Gene Promoter ◽  
Minimal Promoter ◽  
Intestinal Epithelial ◽  
Minimal Promoter Region

Our previous studies have identified a minimal Sp1-driven promoter region (nt −36/+116) directing NHE2 expression in mouse renal epithelial cells. However, this minimal promoter region was not sufficient to support active transcription of NHE2 gene in the intestinal epithelial cells, suggesting the need for additional upstream regulatory elements. In the present study, we used nontransformed rat intestinal epithelial (RIE) cells as a model to identify the minimal promoter region and transcription factors necessary for the basal transcription of rat NHE2 gene in the intestinal epithelial cells. We identified a region within the rat NHE2 gene promoter located within nt −67/−43 upstream of transcription initiation site as indispensable for the promoter function in intestinal epithelial cells. Mutations at nt −56/−51 not only abolished the DNA-protein interaction in this region, but also completely abolished NHE2 gene promoter activity in RIE cells. Supershift assays revealed that Sp1 and Sp3 interact with this promoter region, but, contrary to the minimal promoter indispensable for renal expression of NHE2, both transcription factors expressed individually in Drosophila SL2 cells activated rat NHE2 gene promoter. Moreover, Sp1 was a weaker transactivator and when coexpressed in SL2 cells it reduced Sp3-mediated NHE2 basal promoter activity. Furthermore, DNase I footprinting confirmed that nt −58/−51 is protected by nuclear protein from RIE cells. We conclude that the mechanism of basal control of rat NHE2 gene promoter activity is different in the renal and intestinal epithelium, with Sp3 being the major transcriptional activator of NHE2 gene transcription in the intestinal epithelial cells.

scholarly journals Sodium butyrate stimulates NHE8 expression via its role on activating NHE8 basal promoter activity

2015 ◽  
Vol 309 (6) ◽  
pp. G500-G505 ◽  
Author(s):  
Hua Xu ◽  
Anthony McCoy ◽  
Jing Li ◽  
Yang Zhao ◽  
Fayez K. Ghishan
Keyword(s):  
Epithelial Cells ◽  
Mrna Expression ◽  
Promoter Region ◽  
Intestinal Epithelial Cells ◽  
Gene Promoter ◽  
Sodium Absorption ◽  
Intestinal Epithelial ◽  
Mobility Shift ◽  
Bacterial Fermentation ◽  
Butyrate Treatment

Butyrate is a major metabolite in colonic lumen. It is produced from bacterial fermentation of dietary fiber. Butyrate has been shown to stimulate electroneutral sodium absorption through its regulation on sodium/hydrogen exchanger 3 (NHE3). Although NHE8, the newest addition of intestinal NHE family, is involved in sodium absorption in the intestinal tract, whether butyrate modulates NHE8 expression in the intestinal epithelial cells is not known. In the current study, we showed that butyrate treatment strongly induced NHE8 protein and NHE8 mRNA expression in human intestinal epithelial cells. Transfection with the human NHE8 promoter reporter constructs showed that butyrate treatment stimulated reporter gene expression at an amount comparable with its stimulation of NHE8 mRNA expression. Interestingly, a similar result was also observed in human NHE8 promoter transfected cells after trichostatin (TSA) treatment. Gel mobility shift assay identified an enhanced Sp3 protein binding on the human NHE8 basal promoter region upon butyrate stimulation. Furthermore, Sp3 acetylation modification is involved in butyrate-mediated NHE8 activation in Caco-2 cells. Our findings suggest that the mechanism of butyrate action on NHE8 expression involves enhanced Sp3 interaction at the basal promoter region of the human NHE8 gene promoter to activate NHE8 gene transcription. Thus butyrate is involved in intestinal regulation of NHE8 resulting enhanced sodium absorption.

scholarly journals LPA stimulates intestinal DRA gene transcription via LPA2 receptor, PI3K/AKT, and c-Fos-dependent pathway

2012 ◽  
Vol 302 (6) ◽  
pp. G618-G627 ◽  
Author(s):  
Amika Singla ◽  
Anoop Kumar ◽  
Shubha Priyamvada ◽  
Maliha Tahniyath ◽  
Seema Saksena ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Gene Transcription ◽  
Promoter Activity ◽  
Intestinal Epithelial Cells ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Short Term ◽  
Exchange Activity

DRA (downregulated in adenoma) or SLC26A3 is the major apical anion exchanger mediating Cl− absorption in intestinal epithelial cells. Disturbances in DRA function and expression have been implicated in diarrheal conditions such as congenital chloride diarrhea and inflammatory bowel diseases. Previous studies have shown that DRA is subject to regulation by short-term and transcriptional mechanisms. In this regard, we have recently shown that short-term treatment by lysophosphatidic acid (LPA), an important bioactive phospholipid, stimulates Cl−/HCO3−(OH−) exchange activity via an increase in DRA surface levels in human intestinal epithelial cells. However, the long-term effects of LPA on DRA at the level of gene transcription have not been examined. The present studies were aimed at investigating the effects of LPA on DRA function and expression as well as elucidating the mechanisms underlying its transcriptional regulation. Long-term LPA treatment increased the Cl−/HCO3− exchange activity in Caco-2 cells. LPA treatment (50–100 μM) of Caco-2 cells significantly stimulated DRA mRNA levels and DRA promoter activity (−1183/+114). This increase in DRA promoter activity involved the LPA2 receptor and phosphatidylinositol 3-kinase (PI3K)/AKT pathways. Progressive deletions from −1183/+114 to −790/+114 abrogated the stimulatory effects of LPA, indicating that the −1183/−790 promoter region harbors LPA response elements. Utilizing EMSA and mutational studies, our results showed that LPA induced the DRA promoter activity in a c-Fos-dependent manner. LPA also increased the protein expression of c-Fos and c-Jun in Caco-2 cells. Furthermore, overexpression of c-Fos but not c-Jun enhanced the DRA promoter activity. This increase in DRA transcription in response to LPA indicates that LPA may act as an antidiarrheal agent and could be exploited for the treatment of diarrhea associated with inflammatory or infectious diseases of the gut.

scholarly journals Transcriptional inhibition of intestinal NHE8 expression by glucocorticoids involves Pax5

2010 ◽  
Vol 299 (4) ◽  
pp. G921-G927 ◽  
Author(s):  
Hua Xu ◽  
Bo Zhang ◽  
Jing Li ◽  
Huacong Chen ◽  
Chunhui Wang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Promoter Activity ◽  
Intestinal Epithelial Cells ◽  
Gene Promoter ◽  
High Expression ◽  
Male Rats ◽  
Proximal Promoter ◽  
Sodium Absorption ◽  
Intestinal Epithelial ◽  
Intestinal Maturation

Sodium/hydrogen exchangers (NHEs) are a family of proteins that transport sodium ions into the cells by moving protons out of the cells. They play a major role in sodium absorption, cell volume regulation, and intracellular pH regulation. Three out of nine identified NHEs (NHE2, NHE3, and NHE8) are expressed on the apical membrane of intestinal epithelial cells. Glucocorticoids have been found to regulate NHE3 function in the intestine, but it is unknown if they have a similar function on NHE8 expression. Interestingly, high glucocorticoid levels in the intestine coincide chronologically with the change from high expression of NHE8 to high expression of NHE3. Studies were performed to explore the role of glucocorticoids on NHE8 expression during intestinal maturation. Brush-border membrane vesicles were isolated from intestinal epithelia, and Western blotting was performed to determine NHE8 protein expression of suckling male rats treated with methylpredisolone. Real-time PCR was used to quantitate NHE8 mRNA expression in rats and Caco-2 cells. Human NHE8 promoter activity was characterized through transfection of Caco-2 cells. Gel mobility shift assays (GMSAs) were used to identify the promoter sequences and the transcription factors involved in glucocorticoid-mediated regulation. Our results showed that the expression of NHE8 mRNA and protein was decreased in glucocorticoid-treated rats and human intestinal epithelial cells (Caco-2). The activity of the human NHE8 gene promoter transfected in Caco-2 cells was also reduced by glucocorticoid treatment. GMSAs suggested that the reduction in promoter activity in the presence of glucocorticoids was due to enhanced transcription factor Pax5 binding on the NHE8 proximal promoter region. In conclusion, this study showed that glucocorticoids inhibit NHE8 gene expression by increasing Pax5 binding on NHE8 gene promoter, suggesting an important role for Pax5 during intestinal maturation.

scholarly journals Induced JunD in intestinal epithelial cells represses CDK4 transcription through its proximal promoter region following polyamine depletion

2007 ◽  
Vol 403 (3) ◽  
pp. 573-581 ◽  
Author(s):  
Lan Xiao ◽  
Jaladanki N. Rao ◽  
Tongtong Zou ◽  
Lan Liu ◽  
Bernard S. Marasa ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cells ◽  
Promoter Region ◽  
Promoter Activity ◽  
Intestinal Epithelial Cells ◽  
Ectopic Expression ◽  
Proximal Promoter ◽  
Transcriptional Level ◽  
Intestinal Epithelial ◽  
Proximal Promoter Region

Maintenance of intestinal epithelial integrity requires cellular polyamines that regulate expression of various genes involved in cell proliferation, growth arrest and apoptosis. In prior studies, depletion of cellular polyamines has been shown to stabilize JunD, a member of the AP-1 (activator protein-1) family of transcription factors, leading to inhibition of intestinal epithelial cell proliferation, but the exact downstream targets of induced JunD remain elusive. CDK4 (cyclin-dependent kinase 4) is essential for the G1- to S-phase transition during the cell cycle and its expression is primarily controlled at the transcriptional level. In the present study, we show that induced JunD in IECs (intestinal epithelial cells) is a transcriptional repressor of the CDK4 gene following polyamine depletion. Increased JunD in polyamine-deficient cells was associated with a significant inhibition of CDK4 transcription, as indicated by repression of CDK4-promoter activity and decreased levels of CDK4 mRNA and protein, all of which were prevented by using specific antisense JunD oligomers. Ectopic expression of the wild-type junD also repressed CDK4-promoter activity and decreased levels of CDK4 mRNA and protein without any effect on CDK2 expression. Gel shift and chromatin immunoprecipitation assays revealed that JunD bound to the proximal region of the CDK4-promoter in vitro as well as in vivo, while experiments using different CDK4-promoter mutants showed that transcriptional repression of CDK4 by JunD was mediated through an AP-1 binding site within this proximal sequence of the CDK4-promoter. These results indicate that induced JunD in IECs represses CDK4 transcription through its proximal promoter region following polyamine depletion.

scholarly journals HNF4α and CDX2 Regulate Intestinal YAP1 Promoter Activity

2019 ◽  
Vol 20 (12) ◽  
pp. 2981 ◽  
Author(s):  
Larsen ◽  
Davidsen ◽  
Dahlgaard ◽  
Pedersen ◽  
Troelsen
Keyword(s):  
Epithelial Cells ◽  
Promoter Activity ◽  
Intestinal Epithelial Cells ◽  
Hippo Pathway ◽  
Bioinformatic Analysis ◽  
Intestinal Epithelial ◽  
Mobility Shift ◽  
Enhancer Activity ◽  
The Hippo Pathway

The Hippo pathway is important for tissue homeostasis, regulation of organ size andgrowth in most tissues. The co‐transcription factor yes‐associated protein 1 (YAP1) serves as a maindownstream effector of the Hippo pathway and its dysregulation increases cancer development andblocks colonic tissue repair. Nevertheless, little is known about the transcriptional regulation ofYAP1 in intestinal cells. The aim of this study to identify gene control regions in the YAP1 gene andtranscription factors important for intestinal expression. Bioinformatic analysis of caudal typehomeobox 2 (CDX2) and hepatocyte nuclear factor 4 alpha (HNF4α) chromatin immunoprecipitatedDNA from differentiated Caco‐2 cells revealed potential intragenic enhancers in the YAP1 gene.Transfection of luciferase‐expressing YAP1 promoter‐reporter constructs containing the potentialenhancer regions validated one potent enhancer of the YAP1 promoter activity in Caco‐2 and T84cells. Two potential CDX2 and one HNF4α binding sites were identified in the enhancer by in silicotranscription factor binding site analysis and protein‐DNA binding was confirmed in vitro usingelectrophoretic mobility shift assay. It was found by chromatin immunoprecipitation experimentsthat CDX2 and HNF4α bind to the YAP1 enhancer in Caco‐2 cells. These results reveal a previouslyunknown enhancer of the YAP1 promoter activity in the YAP1 gene, with importance for highexpression levels in intestinal epithelial cells. Additionally, CDX2 and HNF4α binding areimportant for the YAP1 enhancer activity in intestinal epithelial cells.

scholarly journals Regulation of basal promoter activity of the human thiamine pyrophosphate transporter SLC44A4 in human intestinal epithelial cells

2015 ◽  
Vol 308 (9) ◽  
pp. C750-C757 ◽  
Author(s):  
Svetlana M. Nabokina ◽  
Mel Brendan Ramos ◽  
Judith E. Valle ◽  
Hamid M. Said
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Epithelial Cells ◽  
Promoter Activity ◽  
Minimal Promoter ◽  
Thiamine Pyrophosphate ◽  
Luciferase Reporter ◽  
Uptake System ◽  
Colonic Epithelial Cells ◽  
Basal Promoter Activity

Microbiota of the large intestine synthesize considerable amount of vitamin B1 in the form of thiamine pyrophosphate (TPP). There is a specific high-affinity regulated carrier-mediated uptake system for TPP in human colonocytes (product of the SLC44A4 gene). The mechanisms of regulation of SLC44A4 gene expression are currently unknown. In this study, we characterized the SLC44A4 minimal promoter region and identified transcription factors important for basal promoter activity in colonic epithelial cells. The 5′-regulatory region of the SLC44A4 gene (1,022 bp) was cloned and showed promoter activity upon transient transfection into human colonic epithelial NCM460 cells. With the use of a series of 5′- and 3′-deletion luciferase reporter constructs, the minimal genomic region that required basal transcription of the SLC44A4 gene expression was mapped between nucleotides −178 and +88 (using the distal transcriptional start site as +1). Mutational analysis performed on putative cis-regulatory elements established the involvement of ETS/ELF3 [E26 transformation-specific sequence (ETS) proteins], cAMP-responsive element (CRE), and SP1/GC-box sequence motifs in basal SLC44A4 promoter activity. By means of EMSA, binding of ELF3 and CRE-binding protein-1 (CREB-1) transcription factors to the SLC44A4 minimal promoter was shown. Contribution of CREB into SLC44A4 promoter activity was confirmed using NCM460 cells overexpressing CREB. We also found high expression of ELF3 and CREB-1 in colonic (NCM460) compared with noncolonic (ARPE19) cells, suggesting their possible contribution to colon-specific pattern of SLC44A4 expression. This study represents the first characterization of the SLC44A4 promoter and reports the importance of both ELF3 and CREB-1 transcription factors in the maintenance of basal promoter activity in colonic epithelial cells.

scholarly journals Regulation of NF-κB responses by epigenetic suppression of IκBα expression in HCT116 intestinal epithelial cells

2010 ◽  
Vol 299 (1) ◽  
pp. G96-G105 ◽  
Author(s):  
Angela O'Gorman ◽  
Amy Colleran ◽  
Aideen Ryan ◽  
Jelena Mann ◽  
Laurence John Egan
Keyword(s):  
Epithelial Cells ◽  
Tumor Necrosis ◽  
Tumor Necrosis Factor Α ◽  
Intestinal Epithelial Cells ◽  
Gene Promoter ◽  
Intestinal Epithelial ◽  
Epigenetic Factors ◽  
Factor Α ◽  
Necrosis Factor ◽  
Hct116 Cells

Intestinal epithelial cells play critical roles in regulating mucosal immunity. Since epigenetic factors such as DNA methylation and histone modifications are implicated in aging, carcinogenesis, and immunity, we set out to assess any role for epigenetic factors in the regulation of intestinal epithelial cell immune responses. Experiments were conducted using the HCT116 cell line, and a subclone was genetically engineered to lack DNA methyltransferases (DNMT). The induction of the chemokine interleukin-8 and the antiapoptotic protein cFLIP by tumor necrosis factor-α were markedly less in HCT116 cells lacking DNMT than in parental cells. These effects were accompanied by lower monocyte chemotaxis and higher caspase signaling in HCT116 cells lacking DNMT than parental cells. Tumor necrosis factor-α-induced NF-κB activation was blocked and IκBα expression was higher in HCT116 cells lacking DNMT than in parental cells. A CpG island in the IκBα gene promoter region was found to contain variable levels of methylation in parental HCT116 cells. Chromatin immunoprecipitation analysis of histone proteins bound to the IκBα gene promoter revealed that higher levels of IκBα expression in HCT116 cells lacking DNMT compared with parental cells were accompanied by more chromatin marks permissive to gene transcription. These findings show that epigenetic factors influence the NF-κB system in intestinal epithelial cells, resulting in a previously unrecognized mechanism of innate immune regulation.

scholarly journals A host cell long noncoding RNA NR_033736 regulates type I interferon-mediated gene transcription and modulates intestinal epithelial anti-Cryptosporidium defense

2021 ◽  
Vol 17 (1) ◽  
pp. e1009241
Author(s):  
Juan Li ◽  
Kehua Jin ◽  
Min Li ◽  
Nicholas W. Mathy ◽  
Ai-Yu Gong ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Host Cell ◽  
Gene Transcription ◽  
Intestinal Epithelial Cells ◽  
Immune Defense ◽  
Fine Tuning ◽  
Type I ◽  
Intestinal Epithelial ◽  
Type I Ifn ◽  
Innate Defense

The gastrointestinal epithelium guides the immune system to differentiate between commensal and pathogenic microbiota, which relies on intimate links with the type I IFN signal pathway. Epithelial cells along the epithelium provide the front line of host defense against pathogen infection in the gastrointestinal tract. Increasing evidence supports the regulatory potential of long noncoding RNAs (lncRNAs) in immune defense but their role in regulating intestinal epithelial antimicrobial responses is still unclear. Cryptosporidium, a protozoan parasite that infects intestinal epithelial cells, is an important opportunistic pathogen in AIDS patients and a common cause of diarrhea in young children in developing countries. Recent advances in Cryptosporidium research have revealed a strong type I IFN response in infected intestinal epithelial cells. We previously identified a panel of host cell lncRNAs that are upregulated in murine intestinal epithelial cells following microbial challenge. One of these lncRNAs, NR_033736, is upregulated in intestinal epithelial cells following Cryptosporidium infection and displays a significant suppressive effect on type I IFN-controlled gene transcription in infected host cells. NR_033736 can be assembled into the ISGF3 complex and suppresses type I IFN-mediated gene transcription. Interestingly, upregulation of NR_033736 itself is triggered by the type I IFN signaling. Moreover, NR_033736 modulates epithelial anti-Cryptosporidium defense. Our data suggest that upregulation of NR_033736 provides negative feedback regulation of type I IFN signaling through suppression of type I IFN-controlled gene transcription, and consequently, contributing to fine-tuning of epithelial innate defense against microbial infection.

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