Papers by Carsten Carlberg
Frontiers of Hormone Research, 1997
Personalized Medicine, 2014
Mechanisms of Gene Regulation, 2013
Nuclear Receptors, 2010
ABSTRACT
Mechanisms of Gene Regulation, 2013
Canadian journal of physiology and pharmacology, Jan 21, 2015
Vitamin D3 is one of the few natural compounds that has, via its metabolite 1α,25-dihydroxyvitami... more Vitamin D3 is one of the few natural compounds that has, via its metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) and the transcription factor vitamin D receptor (VDR), a direct effect on gene regulation. For efficiently applying the therapeutic and disease-preventing potential of 1,25(OH)2D3 and its synthetic analogs, the key steps in vitamin D signaling need to be understood. These are the different types of molecular interactions with the VDR, such as (i) the complex formation of VDR with genomic DNA, (ii) the interaction of VDR with its partner transcription factors, (iii) the binding of 1,25(OH)2D3 or its synthetic analogs within the ligand-binding pocket of the VDR, and (iv) the resulting conformational change on the surface of the VDR leading to a change of the protein-protein interaction profile of the receptor with other proteins. This review will present the latest genome-wide insight into vitamin D signaling, and will discuss its therapeutic implications.
Frontiers in physiology, 2014
For a global understanding of the physiological impact of the nuclear hormone 1α,25-dihydroxyvita... more For a global understanding of the physiological impact of the nuclear hormone 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) the analysis of the genome-wide locations of its high affinity receptor, the transcription factor vitamin D receptor (VDR), is essential. Chromatin immunoprecipitation sequencing (ChIP-seq) in GM10855 and GM10861 lymphoblastoid cells, undifferentiated and lipopolysaccharide-differentiated THP-1 monocytes, LS180 colorectal cancer cells and LX2 hepatic stellate cells revealed between 1000 and 13,000 VDR-specific genomic binding sites. The harmonized analysis of these ChIP-seq datasets indicates that the mechanistic basis for the action of the VDR is independent of the cell type. Formaldehyde-assisted isolation of regulatory elements sequencing (FAIRE-seq) data highlight accessible chromatin regions, which are under control of 1,25(OH)2D3. In addition, public data, such as from the ENCODE project, allow to relate the genome-wide actions of VDR and 1,25(OH)2D3 to those o...
Anticancer research, 2012
The transcription factor vitamin D receptor (VDR) is the nuclear sensor for the biologically most... more The transcription factor vitamin D receptor (VDR) is the nuclear sensor for the biologically most active metabolite of vitamin D, 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)). The physiological actions of the VDR and its ligand are not only the well-known regulation of calcium and phosphorus uptake and transport controlling bone formation, but also their significant involvement in the control of immune functions and of cellular growth and differentiation. For a general understanding of the mechanisms of 1α,25(OH)(2)D(3) signaling, it is essential to monitor the genome-wide location of VDR in relation to primary 1α,25(OH)(2)D(3) target genes. Within the last months, two chromatin immunoprecipitation sequencing (ChIP-Seq) studies using cells of the hematopoietic system, lymphoblastoids and monocytes, were published. The reports indicated the existence of 2776 and 1820 1α,25(OH)(2)D(3)-stimulated VDR-binding sites, comparable numbers, of which, however, only 18.2% overlapped. The two...
Endocrine, 1996
The nuclear hormone 1 α,25-dihydroxyvitamin D(3) (VD) is an important regulator of calcium homeos... more The nuclear hormone 1 α,25-dihydroxyvitamin D(3) (VD) is an important regulator of calcium homeostasis and is also a modulator of the cell cycle. The genomic actions of the hormone are mediated by a single transcription factor, the vitamin D(3) receptor (VDR). On the majority of the known VD response elements, VDR binds as heterodimeric complex with the retinoid X receptor (RXR), which is a member of the nuclear receptor superfamily like VDR. RXR supports not only the DNA binding affinity and specificity of VDR, but allosterically also its transactivation properties. Moreover RXR is a partner in other hormone response systems, which supports the idea that the different nuclear hormone signaling pathways are functionally linked.
Molecular pharmacology, 2001
Two structurally different antagonists of the nuclear hormone 1alpha,25-dihydroxyvitamin D(3) [1a... more Two structurally different antagonists of the nuclear hormone 1alpha,25-dihydroxyvitamin D(3) [1alpha,25(OH)(2)D(3)], the 25-carboxylic ester ZK159222 and the 26,23-lactone TEI-9647, have recently been described. In this study, the molecular mechanisms and the efficacy of both antagonists were compared. ZK159222 showed similar potency and sensitivity to 1alpha,25(OH)(2)D(3) in ligand-dependent gel shift assays using the vitamin D receptor (VDR), the retinoid X receptor, and specific DNA binding sites, whereas TEI-9647 displayed reduced potency and >10-fold lower sensitivity in this assay system. Limited protease digestion and gel shift clipping assays showed that the two antagonists stabilized individual patterns of VDR conformations. Both antagonists prevented the interaction of the VDR with coactivator proteins, as demonstrated by GST-pull-down and supershift assays; like the natural hormone, however, they were able to induce a dissociation of corepressor proteins. Interestingl...
Molecular Nutrition & Food Research, 2014
Scope: Vitamin D 3 , its biologically most active metabolite 1␣,25-dihydroxyvitamin D 3 (1,25(OH)... more Scope: Vitamin D 3 , its biologically most active metabolite 1␣,25-dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ), and the vitamin D receptor (VDR) are important for adipose tissue biology. Methods and results: We extrapolated genomic VDR association loci in adipocytes from 55 conserved genome-wide VDR-binding sites in nonfat tissues. Taking the genes DUSP10, TRAK1, NRIP1, and THBD as examples, we confirmed the predicted VDR binding sites upstream of their transcription start sites and showed rapid mRNA up-regulation of all four genes in SGBS human pre-adipocytes. Using adipose tissue biopsy samples from 47 participants of a 5-month vitamin D 3 intervention study, we demonstrated that all four primary VDR target genes can serve as biomarkers for the vitamin D 3 responsiveness of human individuals. Changes in DUSP10 gene expression appear to be the most comprehensive marker, while THBD mRNA changes characterized a rather different group of study participants. Conclusion: We present a new approach to predict vitamin D target genes based on conserved genomic VDR-binding sites. Using human adipocytes as examples, we show that such ubiquitous VDR target genes can be used as markers for the individual's response to a supplementation with vitamin D 3 .
The journal of investigative dermatology. Symposium proceedings / the Society for Investigative Dermatology, Inc. [and] European Society for Dermatological Research, 1996
The molecular structure of the biological active form of vitamin D, 1 alpha,25-dihydroxyvitamin D... more The molecular structure of the biological active form of vitamin D, 1 alpha,25-dihydroxyvitamin D3 (VD), and the vitamin A derivatives all-trans and 9-cis retinoic acid (RA) are not related. The nuclear receptors for VD (VDR) and retinoids (RAR and RXR), however, are members of the same superfamily of ligand-activated transcription factors. We observed stable VDR-RXR and VDR-RAR heterodimers in solution and their transcriptional activity on different types of response elements. Both heterodimeric complexes are activated by VD, but, depending on the relative expression of the nuclear receptors, retinoids can have either co-stimulating or repressing effects. This demonstrates that VD and retinoid signaling are linked at the level of gene regulation and may explain the similar effects of both hormones on cell proliferation and differentiation. This concept may be applied for treating skin diseases, with the hope that a synergism will be observed, allowing better responses with lower do...
The journal of investigative dermatology. Symposium proceedings / the Society for Investigative Dermatology, Inc. [and] European Society for Dermatological Research, 1996
Nuclear signaling by 1 alpha, 25-dihydroxyvitamin D3 (VD) is mediated by its nuclear receptor (VD... more Nuclear signaling by 1 alpha, 25-dihydroxyvitamin D3 (VD) is mediated by its nuclear receptor (VDR). It is widely accepted that VDR forms heterodimers with retinoid X receptors (RXRs) that bind in 5'-RXR-VDR-3' polarity to response elements formed by direct repeats of hexameric core binding motifs spaced by three nucleotides. This model, however, might be too simple to explain the multiplicity of nuclear signaling by VD. Recently, it was reported that VDR forms homodimers and heterodimers with the nuclear receptors for all-trans retinoic acid and thyroid hormone. All four different VDR complexes bind not only to direct repeats, but also to inverted palindromes; moreover, in heterodimeric complexes VDR can also take the 5' position. Taken together, this discriminates at least seven different types of VDR complexes binding each to two types of response elements. For half of these 14 cases, representative natural VD response elements have already been identified, which demo...
The Biochemical journal, Jan 15, 1997
The nuclear hormone 1alpha,25-dihydroxyvitamin D3 (VD) has important cell regulatory functions. V... more The nuclear hormone 1alpha,25-dihydroxyvitamin D3 (VD) has important cell regulatory functions. Various synthetic VD analogues are under investigation to identify candidates with an improved therapeutic profile against hyperproliferative diseases. VD directly activates the transcription factor VD receptor (VDR), which in turn stimulates the expression of a cascade of primary and secondary VD-responsive genes. The activation of the VDR through binding of its natural and synthetic ligands is linked to a conformational change presenting the interface with co-activator proteins, referred to as the (trans)activation function 2 (AF-2) domain. Multiple conformations of the VDR might be the key to understanding a selective action of VD analogues. The method of limited protease digestion was used here to characterize up to three different functional VDR conformations stabilized individually by VD and its analogues. The relative potency of VDR ligands can be quantified in the interaction with...
The Journal of biological chemistry, Jan 25, 1993
The nuclear signaling pathways for retinoids and vitamin D differ in the specificity of the respe... more The nuclear signaling pathways for retinoids and vitamin D differ in the specificity of the respective receptors for response elements. Two pathways for the action of both retinoic acid receptors (RARs) and vitamin D receptors (VDRs) have been identified, one being retinoid X receptor (RXR)-dependent and the other being RXR-independent. Moreover, RXRs were found to function as homodimers. In several steps we converted the retinoid specific response element of the human retinoic acid receptor beta promoter into the vitamin D/retinoic acid response element of the human osteocalcin promoter. We found that VDR homodimers only bind to the motif RGGTGA. The extended osteocalcin element also contains an imperfect direct repeat based on the motif RGGTGA spaced by three nucleotides, which is bound by RXR homodimers and activated by 9-cis-retinoic acid. The responsiveness of the osteocalcin element to all-trans-retinoic acid is mediated neither by RAR homodimers nor by RAR-RXR heterodimers. H...
The Biochemical journal, Jan 15, 1993
The pleiotropic activities of retinoids are mediated by two types of nuclear receptors, the retin... more The pleiotropic activities of retinoids are mediated by two types of nuclear receptors, the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs). All-trans-retinoic acid (RA) transcriptionally activates RARs, but not RXRs, whereas its natural stereoisomer, 9-cis-RA, is the ligand for RXRs. Here, we demonstrate that 9-cis-RA did not transcriptionally activate RARs, whereas in the presence of all-trans-RA the transactivation of RARs was inhibited in a dose-dependent manner by 9-cis-RA. RAR homodimer complexes were destabilized in vitro in the presence of 9-cis-RA. This suggests that 9-cis-RA may be a natural antagonist of all-trans-RA for binding to RAR complexes. The levels of 9-cis-RA may determine by which pathway the transcription of retinoid-responsive genes is modulated.
The Journal of biological chemistry, Jan 4, 1994
The thyroid hormone (3,5,3'-triiodothyronine) receptor (T3R) belongs to the nuclear receptor ... more The thyroid hormone (3,5,3'-triiodothyronine) receptor (T3R) belongs to the nuclear receptor superfamily of ligand-inducible transcription factors. T3Rs are known to bind as homodimers and heterodimers with retinoid X receptors (RXRs) to two hexameric half-sites in directly repeated, palindromic, and inverted palindromic orientations. The binding of T3R monomers to individual half-sites was often reported, but no clear ligand-induced transactivational activity has been shown. Here, we analyzed interactions of T3R monomers with individual half-sites of the sequence NNAGGTCA. We found that the two nucleotides 5' of the AGGTCA core half-site strongly influence T3R binding and transcriptional activity: octameric half-sites of the consensus sequence (T/C)(A/G)AGGTCA were bound by T3Rs with the highest affinity. This suggests T3R functioning also as a monomeric transcription factor like the orphan nuclear receptors NGFI-B and FTZ-F1. Moreover, we observed that the function of T3R-...
The Journal of biological chemistry, Jan 25, 1994
Cellular responsiveness to 1,25-dihydroxyvitamin D3 (VD) is conferred by its intracellular recept... more Cellular responsiveness to 1,25-dihydroxyvitamin D3 (VD) is conferred by its intracellular receptor (VDR), which belongs to the nuclear receptor superfamily of ligand-inducible transcription factors. VDRs are known to bind to specific response elements in the promoter region of VD-regulated genes. Two types of natural VD response elements (VDREs) have been identified so far. One is bound by VDR homodimers and is found in the human osteocalcin gene promoter (DR6-type), and the other is bound by heterodimers of VDR with retinoid X receptors (RXRs) as in the mouse osteopontin promoter (DR3-type). Here, we demonstrate that VDRs directly interact in solution not only with RXR but also with retinoid acid receptors (RARs) and, interestingly, with thyroid hormone receptors (T3Rs). All three heterodimeric partners were able to enhance the in vitro DNA binding affinity of VDR as compared to VDR homodimers, but they showed different affinities for the two types of VDREs, as determined by Scatc...
Molecular and cellular biology, 1995
VDR, the nuclear receptor for 1,25-dihydroxyvitamin D3 (VD), is a member of the superfamily of nu... more VDR, the nuclear receptor for 1,25-dihydroxyvitamin D3 (VD), is a member of the superfamily of nuclear hormone receptors and controls multiple aspects of homeostasis, cell growth, and differentiation. VDR can function as a homodimer, but heterodimerization with the retinoid X receptor (RXR), retinoic acid receptor, or thyroid hormone receptor increases its affinity for response elements in the promoter of target genes. All natural VD response elements identified so far consist of direct repeats of a variety of hexameric core binding motifs with a preferential spacing of three nucleotides (DR3s). However, all four VD signalling pathways function also on response elements formed by inverted palindromes, although these sequences were not of natural origin. Here, we report the identification of two VD response elements consisting of inverted palindromes spaced by nine nucleotides (IP9s) in the promoters of the human calbindin D9k gene and the rat osteocalcin gene. Like most DR3-type VD ...
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Papers by Carsten Carlberg