The Vitamin D Receptor Represses Transcription of the Pituitary Transcription Factor Pit-1 Gene without Involvement of the Retinoid X Receptor

2006 ◽  
Vol 20 (4) ◽  
pp. 735-748 ◽  
Author(s):  
Samuel Seoane ◽  
Roman Perez-Fernandez
Keyword(s):  
Vitamin D ◽  
Transcription Factor ◽  
Vitamin D Receptor ◽  
Retinoid X Receptor ◽  
Breast Adenocarcinoma ◽  
Mobility Shift ◽  
Histone Deacetylase 1 ◽  
Protein Levels ◽  
Repressive Effect ◽  
Mcf 7

Abstract Pituitary transcription factor-1 (Pit-1) plays a key role in cell differentiation during organogenesis of the anterior pituitary, and as a transcriptional activator for the pituitary GH and prolactin genes. However, Pit-1 is also expressed in nonpituitary cell types and tissues. In breast tumors, Pit-1 mRNA and protein levels are increased with respect to normal breast, and in MCF-7 human breast adenocarcinoma cells, Pit-1 increases GH secretion and cell proliferation. We report here that 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] administration to MCF-7 cells induces a significant decrease in Pit-1 mRNA and protein levels. By deletion analyses, we mapped a region (located between −147 and −171 bp from the transcription start site of the Pit-1 gene) that is sufficient for the repressive response to 1,25-(OH)2D3. Gel mobility shift and chromatin immunoprecipitation assays confirmed the direct interaction between the vitamin D receptor (VDR) as homodimer (without the retinoid X receptor), and the Pit-1 promoter, supporting the view that Pit-1 is a direct transcriptional target of VDR. Our data also indicate that recruitment of histone deacetylase 1 is involved in this repressive effect. This ligand-dependent Pit-1 gene inhibition by VDR in the absence of the retinoid X receptor seems to indicate a new mechanism of transcriptional repression by 1,25-(OH)2D3.

scholarly journals Cellular Expression Levels of the Vitamin D Receptor Are Critical to Its Transcriptional Regulation by the Pituitary Transcription Factor Pit-1

2007 ◽  
Vol 21 (7) ◽  
pp. 1513-1525 ◽  
Author(s):  
Samuel Seoane ◽  
Isabel Ben ◽  
Viviana Centeno ◽  
Roman Perez-Fernandez
Keyword(s):  
Vitamin D ◽  
Transcription Factor ◽  
Transcriptional Regulation ◽  
Vitamin D Receptor ◽  
Binding Protein ◽  
Target Cells ◽  
Dihydroxyvitamin D3 ◽  
Expression Levels ◽  
1,25 Dihydroxyvitamin D3 ◽  
Mcf 7

Abstract The biological role of 1,25-dihydroxyvitamin D3 has generally been related to calcium homeostasis, but this hormone also has fundamental effects on processes of cellular proliferation and differentiation. The genomic actions of 1,25-dihydroxyvitamin D3 are mediated by the vitamin D receptor (VDR) present in target cells. However, VDR transcriptional regulation is not well understood, probably attributable to the complexity of the VDR gene and its promoter. In the present study, it is demonstrated that administration of the pituitary transcription factor Pit-1 (originally found in the pituitary gland but also present in other nonpituitary cell types and tissues) to the MCF-7 (human breast adenocarcinoma) cell line induces a significant increase in VDR mRNA and protein levels. Conversely, Pit-1-targeted small interference RNA markedly reduced expression of VDR in MCF-7 cells. Reporter gene assays demonstrated that the effect of Pit-1 is mediated by its binding to a region located between −254 and −246 bp from the VDR transcription start site. Selective mutations of this site completely abolished VDR transcription. Chromatin immunoprecipitation analysis showed that binding of Pit-1 to the VDR promoter leads additionally to recruitment of cAMP response element-binding protein binding protein, acetylated histone H4, and RNA polymerase II. Surprisingly, Pit-1 binding also recruits VDR protein to the VDR promoter. Using several cell lines with different levels of VDR expression, it was demonstrated that up-regulation of VDR transcription by Pit-1 is dependent on the presence of VDR protein, suggesting that transcriptional expression of VDR in a given cell type is dependent on, among other factors, its own expression levels.

A cis-acting element in the promoter of human ether à go-go 1 potassium channel gene mediates repression by calcitriol in human cervical cancer cells

2015 ◽  
Vol 93 (1) ◽  
pp. 94-101 ◽  
Author(s):  
V. Cázares-Ordoñez ◽  
R.J. González-Duarte ◽  
L. Díaz ◽  
M. Ishizawa ◽  
S. Uno ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Vitamin D ◽  
Potassium Channel ◽  
Cancer Cells ◽  
Vitamin D Receptor ◽  
Cell Cycle Progression ◽  
Transcriptional Level ◽  
Cis Acting ◽  
Repressive Effect ◽  
Human Cervical Cancer

The human ether à go-go 1 potassium channel (hEAG1) is required for cell cycle progression and proliferation of cancer cells. Inhibitors of hEAG1 activity and expression represent potential therapeutic drugs in cancer. Previously, we have shown that hEAG1 expression is downregulated by calcitriol in a variety of cancer cells. Herein, we provided evidence on the regulatory mechanism involved in such repressive effect in cells derived from human cervical cancer. Our results indicate that repression by calcitriol occurs at the transcriptional level and involves a functional negative vitamin D response element (nVDRE) E-box type in the hEAG1 promoter. The described mechanism in this work implies that a protein complex formed by the vitamin D receptor-interacting repressor, the vitamin D receptor, the retinoid X receptor, and the Williams syndrome transcription factor interact with the nVDRE in the hEAG1 promoter in the absence of ligand. Interestingly, all of these transcription factors except the vitamin D receptor-interacting repressor are displaced from hEAG1 promoter in the presence of calcitriol. Our results provide novel mechanistic insights into calcitriol mode of action in repressing hEAG1 gene expression.

VITAMIN D DERIVATIVES IN COMBINATION WITH 9-cis RETINOIC ACID PROMOTE ACTIVE CELL DEATH IN BREAST CANCER CELLS

1995 ◽  
Vol 14 (3) ◽  
pp. 391-394 ◽  
Author(s):  
S Y James ◽  
A G Mackay ◽  
K W Colston
Keyword(s):  
Breast Cancer ◽  
Vitamin D ◽  
Retinoic Acid ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
P53 Protein ◽  
Protein A ◽  
Therapeutic Implications ◽  
Protein Levels ◽  
Mcf 7

ABSTRACT The effects of the novel vitamin D analogue, EB1089 alone, or in combination with the retinoid, 9-cis retinoic acid (9-cis RA) on indices of apoptosis in MCF-7 breast cancer cells have been examined. EB1089 was capable of reducing bcl-2 protein, a suppressor of apoptosis, and increasing p53 protein levels in MCF-7 cell cultures following 96h treatment. In the presence of 9-cis RA, EB1089 acted to further enhance the down-regulation and up-regulation of bcl-2 and p53 respectively. Furthermore, EB1089 induces DNA fragmentation in MCF-7 cells, a key feature of apoptosis, alone and in combination with 9-cis RA in situ. The observation that EB1089 and 9-cis RA act in a cooperative manner to enhance induction of apoptosis in these cells may have therapeutic implications.

Functional characterization of WT1 binding sites within the human vitamin D receptor gene promoter

2001 ◽  
Vol 7 (2) ◽  
pp. 187-200 ◽  
Author(s):  
TAE HO LEE ◽  
JERRY PELLETIER
Keyword(s):  
Gene Expression ◽  
Vitamin D ◽  
Transcription Factor ◽  
Vitamin D Receptor ◽  
Binding Sites ◽  
Wilms Tumor ◽  
Cdna Array ◽  
Transcriptional Level ◽  
Vdr Gene ◽  
Downstream Target

The Wilms’ tumor suppressor gene, wt1, encodes a zinc finger transcription factor that can regulate gene expression. It plays an essential role in tumorigenesis, kidney differentiation, and urogenital development. To identify WT1 downstream targets, gene expression profiling was conducted using a cDNA array hybridization approach. We confirm herein that the human vitamin D receptor (VDR), a ligand-activated transcription factor, is a WT1 downstream target. Nuclear run on experiments demonstrated that the effect of WT1 on VDR expression is at the transcriptional level. Transient transfection assays, deletion mutagenesis, electrophoretic mobility shift assays, and chromatin immunoprecipitation assays suggest that, although WT1 is presented with a possibility of three binding sites within the VDR promoter, activation of the human VDR gene appears to occur through a single site. This site differs from a previously identified WT1-responsive site in the murine VDR promoter (Maurer U, Jehan F, Englert C, Hübinger G, Weidmann E, DeLucas HF, and Bergmann L. J Biol Chem 276: 3727–3732, 2001). We also show that the products of a Denys-Drash syndrome allele of wt1 inhibit WT1-mediated transactivation of the human VDR promoter. Our results indicate that the human VDR gene is a downstream target of WT1 and may be regulated differently than its murine counterpart.

scholarly journals Niemann-Pick Type A Disease: Behavior of Neutral Sphingomyelinase and Vitamin D Receptor

2019 ◽  
Vol 20 (9) ◽  
pp. 2365 ◽  
Author(s):  
Carmela Conte ◽  
Cataldo Arcuri ◽  
Samuela Cataldi ◽  
Carmen Mecca ◽  
Michela Codini ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Synapse Formation ◽  
Type A ◽  
Acid Sphingomyelinase ◽  
Vdr Gene ◽  
Neutral Sphingomyelinase ◽  
Protein Levels ◽  
Gene And Protein Expression ◽  
Niemann Pick

Sphingomyelinase (SMase) is responsible for the breakdown of sphingomyelin (SM) with production of ceramide. The absence of acid sphingomyelinase (aSMase) causes abnormal synapse formation in Niemann-Pick type A (NPA) disease. Because high levels of ceramide in the NPA brain were demonstrated, the involvement of other SMases were supposed. In the present study we focused the attention on the neurogenic niches in the hippocampal gyrus dentatus (GD), a brain structure essential for forming cohesive memory. We demonstrated for the first time the increase of (Sex determining region Y)-box 2 (SOX2), and the down-regulation of glial fibrillary acidic protein (GFAP) NPA mice GD. Moreover, we found that the expression of Toll like receptors (TLRs), was increased in NPA mice, particularly TLR2, TLR7, TLR8 and TLR9 members. Although no significant change in neutral sphingomyelinase (nSMase) gene expression was detected in the NPA mice hippocampus of, protein levels were enhanced, probably because of the slower protein degradation rate in this area. Many studies demonstrated that vitamin D receptor (VDR) is expressed in the hippocampus GD. Unexpectedly, we showed that NPA mice exhibited VDR gene and protein expression up-regulation. In summary, our study suggests a relation between hippocampal cell differentiation defect, nSMase and VDR increase in NPA mice.

scholarly journals TRAF3 Modulation: Novel Mechanism for the Anti-inflammatory Effects of the Vitamin D Receptor Agonist Paricalcitol in Renal Disease

2020 ◽  
Vol 31 (9) ◽  
pp. 2026-2042 ◽  
Author(s):  
Sandra Rayego-Mateos ◽  
Jose Luis Morgado-Pascual ◽  
José Manuel Valdivielso ◽  
Ana Belén Sanz ◽  
Enrique Bosch-Panadero ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Cultured Cells ◽  
Kidney Injury ◽  
Preclinical Model ◽  
Protein Levels ◽  
Inflammatory State ◽  
Anti Inflammatory ◽  
Injury Models ◽  
Inflammatory Effect

BackgroundCKD leads to vitamin D deficiency. Treatment with vitamin D receptor agonists (VDRAs) may have nephroprotective and anti-inflammatory actions, but their mechanisms of action are poorly understood.MethodsModulation of the noncanonical NF-κB2 pathway and its component TNF receptor–associated factor 3 (TRAF3) by the VDRA paricalcitol was studied in PBMCs from patients with ESKD, cytokine-stimulated cells, and preclinical kidney injury models.ResultsIn PBMCs isolated from patients with ESKD, TRAF3 protein levels were lower than in healthy controls. This finding was associated with evidence of noncanonical NF-κB2 activation and a proinflammatory state. However, PBMCs from patients with ESKD treated with paricalcitol did not exhibit these features. Experiments in cultured cells confirmed the link between TRAF3 and NF-κB2/inflammation. Decreased TRAF3 ubiquitination in K48-linked chains and cIAP1-TRAF3 interaction mediated the mechanisms of paricalcitol action.TRAF3 overexpression by CRISPR/Cas9 technology mimicked VDRA’s effects. In a preclinical model of kidney injury, paricalcitol inhibited renal NF-κB2 activation and decreased renal inflammation. In VDR knockout mice with renal injury, paricalcitol prevented TRAF3 downregulation and NF-κB2–dependent gene upregulation, suggesting a VDR-independent anti-inflammatory effect of paricalcitol.ConclusionsThese data suggest the anti-inflammatory actions of paricalcitol depend on TRAF3 modulation and subsequent inhibition of the noncanonical NF-κB2 pathway, identifying a novel mechanism for VDRA’s effects. Circulating TRAF3 levels could be a biomarker of renal damage associated with the inflammatory state.

scholarly journals 1α,25(OH)2D3-Induced Transrepression by Vitamin D Receptor through E-Box-Type Elements in the Human Parathyroid Hormone Gene Promoter

2007 ◽  
Vol 21 (2) ◽  
pp. 334-342 ◽  
Author(s):  
Mi-sun Kim ◽  
Ryoji Fujiki ◽  
Akiko Murayama ◽  
Hirochika Kitagawa ◽  
Kazuyoshi Yamaoka ◽  
...  
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Gene Promoter ◽  
Negative Regulation ◽  
Retinoid X Receptor ◽  
Gene Promoters ◽  
Histone Deacetylase 2 ◽  
E Box ◽  
Renal Tubule Cell ◽  
Precise Molecular Mechanism

Abstract Although transactivation by the liganded vitamin D receptor (VDR) is well described at the molecular level, the precise molecular mechanism of negative regulation by the liganded VDR remains to be elucidated. We have previously reported a novel class of negative vitamin D response element (nVDRE) called 1αnVDRE in the human 25(OH)D31α-hydroxylase [1α(OH)ase] gene by 1α,25(OH)2D3-bound VDR. This element was composed of two E-box-type motifs that bound to VDIR for transactivation, which was attenuated by liganded VDR. Here, we explore the possible functions of VDIR and E-box motifs in the human (h) PTH and hPTHrP gene promoters. Functional mapping of the hPTH and hPTHrP promoters identified E-box-type elements acting as nVDREs in both the hPTH promoter (hPTHnVDRE; −87 to −60 bp) and in the hPTHrP promoter (hPTHrPnVDRE; −850 to −600 bp; −463 to −104 bp) in a mouse renal tubule cell line. The hPTHnVDRE alone was enough to direct ligand-induced transrepression mediated through VDR/retinoid X receptor and VDIR. Direct DNA binding of hPTHnVDRE to VDIR, but not VDR/retinoid X receptor, was observed and ligand-induced transrepression was coupled with recruitment of VDR and histone deacetylase 2 (HDAC2) to the hPTH promoter. These results suggest that negative regulation of the hPTH gene by liganded VDR is mediated by VDIR directly binding to the E-box-type nVDRE at the promoter, together with recruitment of an HDAC corepressor for ligand-induced transrepression.

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