Biological processes require close cooperation of multiple transcription factors that integrate different signals. Thyroid hormone receptors (TRs) induce Krüppel-like factor 9 (KLF9) to regulate neurogenesis. Here, we show that... more
Biological processes require close cooperation of multiple transcription factors that integrate different signals. Thyroid hormone receptors (TRs) induce Krüppel-like factor 9 (KLF9) to regulate neurogenesis. Here, we show that triiodothyronine (T3) also works through TR to induce KLF9 in HepG2 liver cells, mouse liver, and mouse and human primary hepatocytes and sought to understand TR/KLF9 network function in the hepatocyte lineage and stem cells. Knockdown experiments reveal that KLF9 regulates hundreds of HepG2 target genes and modulates T3 response. Together, T3 and KLF9 target genes influence pathways implicated in stem cell self-renewal and differentiation, including Notch signaling, and we verify that T3 and KLF9 cooperate to regulate key Notch pathway genes and work independently to regulate others. T3 also induces KLF9 in human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSC) and this effect persists during differentiation to definitive endoder...
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Technology, Stem Cells, Biology, Induced Pluripotent Stem Cells (I Psc), Cell Biology, and 15 moreStem Cell, Medicine, Signal Transduction, Biological Sciences, Cell Differentiation, Humans, Mice, Female, Animals, Male, Transcription Factor, Hepatocytes, Pluripotent Stem Cells, Triiodothyronine, and Medical and Health Sciences
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Association studies suggest that the thyroid hormone receptor β1 (TRβ1) could function as a tumor suppressor in cancer cells. However, the underlying molecular mechanisms remain to be elucidated. We explored how TRβ1 acted as a tumor... more
Association studies suggest that the thyroid hormone receptor β1 (TRβ1) could function as a tumor suppressor in cancer cells. However, the underlying molecular mechanisms remain to be elucidated. We explored how TRβ1 acted as a tumor suppressor in breast cancer MDA cells. Proliferation and invasiveness were markedly inhibited in cells stably expressing TRβ1 (MDA-TRβ1 cells). cSrc-phosphorylated TRβ1 at Y406 signaled T3-induced degradation. Mutation of Y406 to Phe (TRβ1Y406F) did not affect T3 binding affinity, but blocked T3-induced degradation in cells. Importantly, cell-based studies showed that TRβ1Y406F lost the inhibitory effects by TRβ1 on cell proliferation and invasion. Consistently, in xenograft models, MDA-TRβ1 cells exhibited significantly slower tumor growth rates than those of Neo control cells. In contrast, the tumor growth rates of MDA-TRβ1Y406F cells were indistinguishable from those of Neo control cells. We further showed that markedly more TRβ1Y406F than TRβ1 was p...
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The early region 1A (E1A) of human adenovirus types 2 and 5 is differentially spliced to yield five distinct mRNAs that encode different proteins. The smallest E1A RNA transcript encodes a 55 residue (55R) protein that shares only 28... more
The early region 1A (E1A) of human adenovirus types 2 and 5 is differentially spliced to yield five distinct mRNAs that encode different proteins. The smallest E1A RNA transcript encodes a 55 residue (55R) protein that shares only 28 amino acid residues with the other E1A proteins. Even though it is the most abundant E1A transcript at late times post-infection, little is known about the functions of this E1A isoform. In this study, we show that the E1A 55R protein interacts with, and modulates the activity of the unliganded thyroid hormone receptor (TR). We demonstrate that E1A 55R contains a signature motif known as the CoRNR box that confers interaction with the unliganded TR; this motif was originally identified in cellular corepressors. Using a system reconstituted in the yeast Saccharomyces cerevisiae, which lack endogenous TR and TR coregulators, we show that E1A 55R nonetheless differs from cellular corepressors as it functions as a strong co-activator of TR-dependent transcr...
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Endocrinology, Chemistry, Diabetes, Biology, Biological Chemistry, and 15 moreMedicine, Biological Sciences, Humans, Internal Medicine, Mice, Animals, Phosphorylation, CHEMICAL SCIENCES, Protein Secondary Structure Prediction, Oral Hypoglycemic Agents, Receptor, Rosiglitazone, Ligands, resistência à insulina, and Medical and Health Sciences
TLX (Tailless Receptor) is a member of the nuclear receptor superfamily and belongs to a class of nuclear receptors for which no endogenous or synthetic ligands have yet been identified. TLX is a promising therapeutic target in... more
TLX (Tailless Receptor) is a member of the nuclear receptor superfamily and belongs to a class of nuclear receptors for which no endogenous or synthetic ligands have yet been identified. TLX is a promising therapeutic target in neurological disorders and brain tumors. Thus, regulatory ligands for TLX need to be identified to complete the validation of TLX as a useful target and would serve as chemical probes to pursue the study of this receptor in disease models. However, the road to identify TLX ligands is challenging. Although it has recently been proved that this receptor is potentially druggable, the lack of structural information on where ligands bind, how they alter TLX conformation and the incomplete characterization of the mechanism by which TLX mediates the transcription of its target genes are obstacles for the discovery of potent and specific TLX ligands with desirable biological activities. While TLX is in the process of escaping from orphanhood, future ligand design needs to progress in parallel with improved understanding of i) the binding cavity or surfaces to target with small molecules on the TLX ligand binding domain and ii) the nature of the TLX coregulators in particular cell and disease contexts. Both of these issues are discussed in this review. This article is part of a Special Issue entitled: Orphan Nuclear Receptors: Escape from Orphanage.
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Engineering, Biochemistry, Biophysics, Chemistry, Biology, and 15 moreInflammatory Immune Response, Crystal structure, Humans, Glucose Metabolism, Delta, Binding, Fatty Acid, Amino Acid Sequence, Insights, Amino Acid Substitution Rates, Activated, Computer Assisted Image Analysis, Cardiac Disease, Inflammatory response, and binding sites
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Background Myelodysplastic Syndromes (MDSS) are pre-leukemic disorders with increasing incident rates worldwide, but very limited treatment options. Little is known about small regulatory RNAs and how they contribute to pathogenesis,... more
Background Myelodysplastic Syndromes (MDSS) are pre-leukemic disorders with increasing incident rates worldwide, but very limited treatment options. Little is known about small regulatory RNAs and how they contribute to pathogenesis, progression and transcriptome changes in MDS. Methods Patients' primary marrow cells were screened for short RNAs (RNA-seq) using next generation sequencing. Exon arrays from the same cells were used to profile gene expression and additional measures on 98 patients obtained. Integrative bioinformatics algorithms were proposed, and pathway and ontology analysis performed. Results In low-grade MDS, observations implied extensive post-transcriptional regulation via microRNAs (miRNA) and the recently discovered Piwi interacting RNAs (piRNA). Large expression differences were found for MDS-associated and novel miRNAs, including 48 sequences matching to miRNA star (miRNA*) motifs. The detected species were predicted to regulate disease stage specific mole...
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Genetics, Computational Biology, MicroRNA, Biology, Transcription Regulation, and 15 moreDNA damage, Medicine, Gene expression, Next generation sequencing, Non Coding Rna, Humans, Myelodysplastic Syndrome, Targeted Therapy, Feedback loop, Nucleic Acid Conformation, Gene Expression Regulation, Gene expression profiling, Incidence Rate, Myelodysplastic syndromes, and Medical biochemistry and metabolomics
Upregulation of estrogen receptor beta (ERβ) in breast cancer cells is associated with epithelial maintenance, decreased proliferation and invasion, and a reduction in the expression of the receptor has been observed in invasive breast... more
Upregulation of estrogen receptor beta (ERβ) in breast cancer cells is associated with epithelial maintenance, decreased proliferation and invasion, and a reduction in the expression of the receptor has been observed in invasive breast tumors. However, proof of an association between loss of ERβ and breast carcinogenesis is still missing. To study the role of ERβ in breast oncogenesis, we generated mouse conditional mutants with specific inactivation of ERβ and p53 in the mammary gland epithelium. For epithelium-specific knockout of ERβ and p53, ERβ (F/F) and p53 (F/F) mice were crossed to transgenic mice that express the Cre recombinase under the control of the human keratin 14 promoter. Somatic loss of ERβ significantly accelerated formation of p53-deficient mammary tumors. Loss of the receptor also resulted in the development of less differentiated carcinomas with stronger spindle cell morphology and decreased expression of luminal epithelial markers. Our results show that synerg...
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Breast Cancer, Biology, Immunohistochemistry, Cancer Research, Medicine, and 15 moreGene expression, Gene Silencing, Epithelial-Mesenchymal Transition, Transgenic Mice, Estrogen Receptor, Mice, Female, Animals, Phenotype, Genotype, Epithelium, Prognosis, alleles, Breast Neoplasms, and Estrogen Receptor beta
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Significance Transcription factor II D (TFIID) is a multiprotein complex that is essential for gene transcription. Together, TATA binding protein-associated factor 1 (TAF1), the biggest TFIID subunit, and TAF7 form an important control... more
Significance Transcription factor II D (TFIID) is a multiprotein complex that is essential for gene transcription. Together, TATA binding protein-associated factor 1 (TAF1), the biggest TFIID subunit, and TAF7 form an important control point for transcriptional initiation. Although current models suggest that TAF7 binds TAF1 to block its intrinsic histone acetyltransferase (HAT) activity, almost nothing is known about the molecular basis of TAF1–TAF7 (TAF1/7) interaction and TAF1 activity. Here, we report the atomic structure of the yeast TAF1/7 heterodimer and probe its function using biochemical techniques. Our structure suggests that yeast TAF1 is not a HAT and instead reveals that TAF1/7 displays the unexpected capacity to bind a specific repressive histone mark. This raises the possibility that TFIID binds repressive chromatin marks to control gene expression.
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In the past year, two members of the nuclear receptor family, liver X receptor β (LXRβ) and thyroid hormone receptor α (TRα), have been found to be essential for correct migration of neurons in the developing cortex in mouse embryos. TRα... more
In the past year, two members of the nuclear receptor family, liver X receptor β (LXRβ) and thyroid hormone receptor α (TRα), have been found to be essential for correct migration of neurons in the developing cortex in mouse embryos. TRα and LXRβ bind to identical response elements on DNA and sometimes regulate the same genes. The reason for the migration defect in the LXRβ −/− mouse and the possibility that TRα may be involved are the subjects of the present study. At E15.5, expression of reelin and VLDLR was similar but expression of apolipoprotein E receptor 2 (ApoER2) (the reelin receptor) was much lower in LXRβ −/− than in WT mice. Knockout of ApoER2 is known to lead to abnormal cortical lamination. Surprisingly, by postnatal day 14 (P14), no morphological abnormalities were detectable in the cortex of LXRβ −/− mice and ApoER2 expression was much stronger than in WT controls. Thus, a postnatal mechanism leads to increase in ApoER2 expression by P14. TRα also regulates ApoER2. I...
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Nuclear receptors are important targets for pharmaceuticals, but similarities between family members cause difficulties in obtaining highly selective compounds. Synthetic ligands that are selective for thyroid hormone (TH) receptor β... more
Nuclear receptors are important targets for pharmaceuticals, but similarities between family members cause difficulties in obtaining highly selective compounds. Synthetic ligands that are selective for thyroid hormone (TH) receptor β (TRβ) vs. TRα reduce cholesterol and fat without effects on heart rate; thus, it is important to understand TRβ-selective binding. Binding of 3 selective ligands (GC-1, KB141, and GC-24) is characterized at the atomic level; preferential binding depends on a nonconserved residue (Asn-331β) in the TRβ ligand-binding cavity (LBC), and GC-24 gains extra selectivity from insertion of a bulky side group into an extension of the LBC that only opens up with this ligand. Here we report that the natural TH 3,5,3′-triodothyroacetic acid (Triac) exhibits a previously unrecognized mechanism of TRβ selectivity. TR x-ray structures reveal better fit of ligand with the TRα LBC. The TRβ LBC, however, expands relative to TRα in the presence of Triac (549 Å 3 vs. 461 Å 3...
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The majority of cholesterol reduction therapies, such as the statin drugs, work primarily by inducing the expression of hepatic low-density lipoprotein receptors (LDLRs), rendering these therapeutics only partially effective in animals... more
The majority of cholesterol reduction therapies, such as the statin drugs, work primarily by inducing the expression of hepatic low-density lipoprotein receptors (LDLRs), rendering these therapeutics only partially effective in animals lacking LDLRs. Although thyroid hormones and their synthetic derivatives, often referred to as thyromimetics, have been clearly shown to reduce serum cholesterol levels, this action has generally been attributed to their ability to increase expression of hepatic LDLRs. Here we show for the first time that the thyroid hormone T3 and the thyroid hormone receptor-β selective agonists GC-1 and KB2115 are capable of markedly reducing serum cholesterol in mice devoid of functional LDLRs by inducing Cyp7a1 expression and stimulating the conversion and excretion of cholesterol as bile acids. Based on this LDLR-independent mechanism, thyromimetics such as GC-1 and KB2115 may represent promising cholesterol-lowering therapeutics for the treatment of diseases su...
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Non-steroidal anti-inflammatory drugs (NSAIDs) display anti-inflammatory, antipyretic and analgesic properties by inhibiting cyclooxygenases and blocking prostaglandin production. Previous studies, however, suggested that some NSAIDs also... more
Non-steroidal anti-inflammatory drugs (NSAIDs) display anti-inflammatory, antipyretic and analgesic properties by inhibiting cyclooxygenases and blocking prostaglandin production. Previous studies, however, suggested that some NSAIDs also modulate peroxisome proliferator activated receptors (PPARs), raising the possibility that such off target effects contribute to the spectrum of clinically relevant NSAID actions. In this study, we set out to understand how peroxisome proliferator activated receptor-γ (PPARγ/PPARG) interacts with NSAIDs using X-ray crystallography and to relate ligand binding modes to effects on receptor activity. We find that several NSAIDs (sulindac sulfide, diclofenac, indomethacin and ibuprofen) bind PPARγ and modulate PPARγ activity at pharmacologically relevant concentrations. Diclofenac acts as a partial agonist and binds to the PPARγ ligand binding pocket (LBP) in typical partial agonist mode, near the β-sheets and helix 3. By contrast, two copies of indome...
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Nuclear Receptor, DNA, Dissociation, Humans, Escherichia coli, and 15 moreLigand Binding, Dynamic Light Scattering, Solutions, Thyroid Receptor, Gel electrophoresis, Amino Acid Sequence, Protein Quaternary Structure, Recombinant Proteins, Protein Binding, DNA binding proteins, Ligands, retinoid X receptor, Biochemistry and cell biology, Dimerization, and Thyroid hormone
Background Thyroid receptors, TRα and TRβ, are involved in important physiological functions such as metabolism, cholesterol level and heart activities. Whereas metabolism increase and cholesterol level lowering could be achieved by TRβ... more
Background Thyroid receptors, TRα and TRβ, are involved in important physiological functions such as metabolism, cholesterol level and heart activities. Whereas metabolism increase and cholesterol level lowering could be achieved by TRβ isoform activation, TRα activation affects heart rates. Therefore, β-selective thyromimetics have been developed as promising drug-candidates for treatment of obesity and elevated cholesterol level. GC-1 [3,5-dimethyl-4-(4'-hydroxy-3'-isopropylbenzyl)-phenoxy acetic acid] has ability to lower LDL cholesterol with 600- to 1400-fold more potency and approximately two- to threefold more efficacy than atorvastatin (Lipitor©) in studies in rats, mice and monkeys. Results To investigate GC-1 specificity, we solved crystal structures and performed molecular dynamics simulations of both isoforms complexed with GC-1. Crystal structures reveal that, in TRα Arg228 is observed in multiple conformations, an effect triggered by the differences in the inter...
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Chemistry, Molecular Dynamics Simulation, Computational Biology, Medicine, Macromolecular X-Ray Crystallography, and 15 moreCrystal structure, Humans, Computer Simulation, Heart rate, LDL-cholesterol, Phenols, HeLa cells, Thyroid Receptor, Interaction effect, Acetic Acid, Protein isoforms, Ligands, Molecular Dynamic Simulation, binding sites, and Molecular dynamic
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We have characterized steroid response elements in mouse mammary tumour virus (MMTV) by transient transfection. Four partial inverted repeats of the sequence TGTTCT function as response elements for androgen, as well as for glucocorticoid... more
We have characterized steroid response elements in mouse mammary tumour virus (MMTV) by transient transfection. Four partial inverted repeats of the sequence TGTTCT function as response elements for androgen, as well as for glucocorticoid and progestins, although the relative hormone inductions mediated by each oligonucleotide were different. Mutational analysis of the left half of the palindrome showed that a perfect dyad symmetry is not required for optimum activity as a steroid response element. To investigate potential interactions between steroid receptors and transcription factors we have analysed the minimum sequence requirements for a hormone response. Interestingly, a single 15 bp steroid response element and a TATA box are sufficient for steroid inductions. When the distance between the two elements was increased by up to two turns of the helix the hormone induction initially increased and then gradually declined with no obvious periodicity.
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Peroxisome proliferator-activated receptor γ (PPARγ) is a target for treatment of type II diabetes and other conditions. PPARγ full agonists, like thiazolidinediones (TZDs), are effective insulin sensitizers and anti-inflammatories but... more
Peroxisome proliferator-activated receptor γ (PPARγ) is a target for treatment of type II diabetes and other conditions. PPARγ full agonists, like thiazolidinediones (TZDs), are effective insulin sensitizers and anti-inflammatories but their use is limited by adverse side effects. Luteolin is flavonoid with anti-inflammatory actions that binds PPARγ but, unlike TZDs, does not promote adipocyte differentiation. However, previous reports variously suggested that luteolin is a PPARγ agonist or an antagonist. We show that luteolin exhibits weak partial agonist/antagonist activity in transfections, inhibits several PPARγ target genes in 3T3-L1 cells (LPL, ORL1 and CBPα) and PPARγ-dependent adipogenesis but activates GLUT4 similarly to rosiglitazone implying gene-specific partial agonism. The crystal structure of the PPARγ ligand binding domain (LBD) reveals that luteolin occupies buried ligand binding pocket (LBP) but binds an inactive PPARγ LBD conformer and occupies a space near the β-...
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Computer Science, Chemistry, Molecular Dynamics Simulation, Molecular Pharmacology, Medicine, and 11 moreHumans, Mice, Animals, Base Sequence, Neurosciences, Gene Expression Regulation, Myristic acid, luteolin, real time polymerase chain reaction, reverse transcriptase polymerase chain reaction, and Pharmacology and pharmaceutical sciences
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Thyroid hormone receptor (TR) agonists have been proposed as therapeutic agents to treat non-alcoholic fatty liver disease (NAFLD) and insulin resistance. We investigated the ability of the TR agonists GC-1 and KB2115 to reduce hepatic... more
Thyroid hormone receptor (TR) agonists have been proposed as therapeutic agents to treat non-alcoholic fatty liver disease (NAFLD) and insulin resistance. We investigated the ability of the TR agonists GC-1 and KB2115 to reduce hepatic steatosis in ob/ob mice. Both compounds markedly reduced hepatic triglyceride levels and ameliorated hepatic steatosis. However, the amelioration of fatty liver was not sufficient to improve insulin sensitivity in these mice and reductions in hepatic triglycerides did not correlate with improvements in insulin sensitivity or glycemic control. Instead, the effects of TR activation on glycemia varied widely and were found to depend upon the time of treatment as well as the compound and dosage used. Lower doses of GC-1 were found to further impair glycemic control, while a higher dose of the same compound resulted in substantially improved glucose tolerance and insulin sensitivity, despite all doses being equally effective at reducing hepatic triglycerid...
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Engineering, Physics, Chemistry, Small angle X-ray and neutron scattering, Mass Spectrometry, and 14 moreBiology, Small Angle X Ray Scattering, Medicine, Multidisciplinary, DNA, Humans, Hydrodynamics, PLoS one, X ray diffraction, Solutions, Amino Acid Sequence, Protein Quaternary Structure, Response Elements, and Molecular Sequence Data
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Thyroid hormones [predominantly 3,5,3′-triiodo-l-thyronine (T 3 )] regulate cholesterol and lipoprotein metabolism, but cardiac effects restrict their use as hypolipidemic drugs. T 3 binds to thyroid hormone receptors (TRs) α and β. TRβ... more
Thyroid hormones [predominantly 3,5,3′-triiodo-l-thyronine (T 3 )] regulate cholesterol and lipoprotein metabolism, but cardiac effects restrict their use as hypolipidemic drugs. T 3 binds to thyroid hormone receptors (TRs) α and β. TRβ is the predominant isoform in liver, whereas T 3 effects on ...
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Biology, Medicine, Multidisciplinary, Liver, Mice, and 15 moreCholesterol, Animals, Male, Hypercholesterolemia, Triglycerides, Phenols, Analysis of Variance, Feces, Thyroid Receptor, Cardiovascular Diseases, Gene Expression Regulation, Serum lipids, Immunoblotting, reverse cholesterol transport, and reverse transcriptase polymerase chain reaction
Members of the 160-kDa nuclear receptor coactivator family (p160 coactivators) bind to the conserved AF-2 activation function found in the hormone binding domains of nuclear receptors (NR) and are potent transcriptional coactivators for... more
Members of the 160-kDa nuclear receptor coactivator family (p160 coactivators) bind to the conserved AF-2 activation function found in the hormone binding domains of nuclear receptors (NR) and are potent transcriptional coactivators for NRs. Here we report that the C-terminal region ...
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Cellular Biology, Nuclear Receptor, Biological Sciences, Cell line, Molecular and cellular biology, and 15 moreHumans, Animals, Chromatin structure, Histone acetyltransferases, DNA binding, Retinoic Acid, Androgen Receptor, Molecular weight, Binding Site, Conformational Change, Full Length Movies, retinoid X receptor, Activation Function, binding sites, and Medical and Health Sciences
Estrogen receptor (ER) is activated either by ligand or by signals from tyrosine kinase-linked cell surface receptors. We investigated whether the nonreceptor Src tyrosine kinase could affect ER activity. Expression of constitutively... more
Estrogen receptor (ER) is activated either by ligand or by signals from tyrosine kinase-linked cell surface receptors. We investigated whether the nonreceptor Src tyrosine kinase could affect ER activity. Expression of constitutively active Src or stimulation of the endogenous ...
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Biology, Transcription Factors, Medicine, Molecular endocrinology, Signal Transduction, and 15 moreEstrogen Receptor, Biological Sciences, Molecular, Humans, Phosphorylation, Proteins, Tamoxifen, HeLa cells, Structure activity Relationship, Cell Surface Markers, Response Elements, Activation Function, Drug synergism, Protein tyrosine kinases, and Medical and Health Sciences
Nuclear receptors (NRs) are conditional transcription factors with common multidomain organization that bind diverse DNA elements. How DNA sequences influence NR conformation is poorly understood. Here we report the crystal structure of... more
Nuclear receptors (NRs) are conditional transcription factors with common multidomain organization that bind diverse DNA elements. How DNA sequences influence NR conformation is poorly understood. Here we report the crystal structure of the human retinoid X receptor α-liver X receptor β (RXRα-LXRβ) heterodimer on its cognate element, an AGGTCA direct repeat spaced by 4 nt. The complex has an extended X-shaped arrangement, with DNA- and ligand-binding domains crossed, in contrast to the parallel domain arrangement of other NRs that bind an AGGTCA direct repeat spaced by 1 nt. The LXRβ core binds DNA via canonical contacts and auxiliary DNA contacts that enhance affinity for the response element. Comparisons of RXRα-LXRβs in the crystal asymmetric unit and with previous NR structures reveal flexibility in NR organization and suggest a role for RXRα in adaptation of heterodimeric complexes to DNA.
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The compound (5Z)-5-[(5-bromo-1H-indol-3-yl)methylene]-3-(4-chlorobenzyl)-thiazolidine-2,4-dione (LYSO-7) was synthesised in order to obtain a new type of anti-inflammatory drug, designed with hybrid features to inhibit cyclooxygenase... more
The compound (5Z)-5-[(5-bromo-1H-indol-3-yl)methylene]-3-(4-chlorobenzyl)-thiazolidine-2,4-dione (LYSO-7) was synthesised in order to obtain a new type of anti-inflammatory drug, designed with hybrid features to inhibit cyclooxygenase (COX) and also to activate peroxisome proliferator-activated receptor (PPAR). Results obtained from docking (in silico) studies corroborated with experimental data, showing the potential affinity between the studied ligand and targets. The specificity of LYSO-7 for COX-enzymes was detected by the inhibition of COX-1 and COX-2 activities by 30% and 20%, respectively. In transactivation reporter gene assays LYSO-07 showed a pan partial agonist effect on the three PPAR subtypes (PPARγ, PPARα and PPARβ/δ). The agonist action on PPARγ was also observed by a pharmacological approach, as the reduction in the Escherichia coli lipopolysaccharide (LPS)-induced interleukin 1 beta (IL-1β) secretion and nitric oxide (NO) production by mouse neutrophils was blocked by GW9962, a specific PPARγ antagonist. Additionally, the in vivo effect was measured by reduced carrageenan-induced neutrophil influx into the subcutaneous tissue of mice. Taken together, these data show that LYSO-7 displays a potent in vivo anti-inflammatory effect during the innate acute response, which is dependent on its associated COX inhibitory activities and PPAR activation.
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Testosterone stimulates the expression of IGF-I in cells and tissues that include prostate, muscle and muscle satellite cells, and the uterus. Here, the molecular mechanisms of this effect of testosterone were explored. Testosterone... more
Testosterone stimulates the expression of IGF-I in cells and tissues that include prostate, muscle and muscle satellite cells, and the uterus. Here, the molecular mechanisms of this effect of testosterone were explored. Testosterone increased IGF-I mRNA levels in HepG2 and LNCaP cells and stimulated the activity of reporter genes controlled by 1.6 kb of the upstream promoter of the human IGF-I gene. An androgen-responsive region that was located between −1320 and −1420 bases upstream of the first codon was identified by truncation studies. The androgen-responsive region was found to contain two sequences resembling known androgen receptor (AR)-binding sites from the Pem1 gene. Reporter genes incorporating these sequences were strongly stimulated by androgens. Each of the androgen-responsive elements (AREs) bound recombinant AR-DNA-binding domain in gel-shift experiments; binding was greatly enhanced by sequences flanking the apparent AR-binding half-sites. Testosterone induced recru...
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Gene regulation, Biology, Biological Chemistry, Medicine, Gene expression, and 15 moreNuclear Receptor, Biological Sciences, Animals, Biological, Glutathione, CHEMICAL SCIENCES, Rats, Gene Targeting, Heart Ventricles, Brain Natriuretic Peptide, Endothelins, Cardiomegaly, Thyroid hormone, Drug synergism, and Medical and Health Sciences
Mutations of a highly conserved DBD lysine (ERα.K206A/G), lead to super-activation of AP-1 through activation function dependent pathways, up to 200 fold. This super-activity can be elicited either through ER AFs 1 or 2, or that of a... more
Mutations of a highly conserved DBD lysine (ERα.K206A/G), lead to super-activation of AP-1 through activation function dependent pathways, up to 200 fold. This super-activity can be elicited either through ER AFs 1 or 2, or that of a heterologous activation function (VP16). The ...
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Antiestrogens, including tamoxifen and raloxifene, block estrogen receptor (ER) action by blocking the interactions of an estrogen-dependent activation function (AF-2) with p160 coactivators. Although tamoxifen does show some agonist... more
Antiestrogens, including tamoxifen and raloxifene, block estrogen receptor (ER) action by blocking the interactions of an estrogen-dependent activation function (AF-2) with p160 coactivators. Although tamoxifen does show some agonist activity in the presence of ERα, this stems from a ...
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Selective estrogen receptor modulators (SERMs) show differential effects upon ERα activation function 1 (AF-1). Tamoxifen allows strong ERα AF-1 activity, whereas raloxifene allows less and ICI 182,780 (ICI) allows none. Here, we show... more
Selective estrogen receptor modulators (SERMs) show differential effects upon ERα activation function 1 (AF-1). Tamoxifen allows strong ERα AF-1 activity, whereas raloxifene allows less and ICI 182,780 (ICI) allows none. Here, we show that blockade of corepressor histone ...
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Biological Chemistry, Medicine, Biological Sciences, Progesterone, Humans, and 15 moreMutation, Plasmids, CHEMICAL SCIENCES, Tamoxifen, HeLa cells, Transfection, Glutathione Transferase, Protein Binding, Estradiol, Histone deacetylases, Selective estrogen receptor modulators, Estrogen receptor alpha, Raloxifene, Estrogen antagonists, and Medical and Health Sciences
Thyroid hormone (TH) receptors (TRs α and β) are homologous ligand-dependent transcription factors (TFs). While the TRs display distinct actions in development, metabolic regulation and other processes, comparisons of TRα and TRβ... more
Thyroid hormone (TH) receptors (TRs α and β) are homologous ligand-dependent transcription factors (TFs). While the TRs display distinct actions in development, metabolic regulation and other processes, comparisons of TRα and TRβ dependent gene regulation mostly reveal similar mechanisms of action and few TR subtype specific genes. Here, we show that TRα predominates in multipotent human adipose derived stem cells (hADSC) whereas TRβ is expressed at lower levels and is upregulated during hADSC differentiation. The TRs display several unusual properties in parental hADSC. First, TRs display predominantly cytoplasmic intracellular distribution and major TRα variants TRα1 and TRα2 colocalize with mitochondria. Second, knockdown experiments reveal that endogenous TRs influence hADSC cell morphology and expression of hundreds of genes in the absence of hormone, but do not respond to exogenous TH. Third, TRα and TRβ affect hADSC in completely distinct ways; TRα regulates cell cycle associ...
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Loss-of-function mutation V290M in the ligand-binding domain of the peroxisome proliferator activated receptor γ (PPARγ) is associated with a ligand resistance syndrome (PLRS), characterized by partial lipodystrophy and severe insulin... more
Loss-of-function mutation V290M in the ligand-binding domain of the peroxisome proliferator activated receptor γ (PPARγ) is associated with a ligand resistance syndrome (PLRS), characterized by partial lipodystrophy and severe insulin resistance. In this data article we discuss an X-ray diffraction dataset that yielded the structure of PPARγ LBD V290M mutant refined at 2.3 Å resolution, that allowed building of 3D model of the receptor mutant with high confidence and revealed continuous well-defined electron density for the partial agonist diclofenac bound to hydrophobic pocket of the PPARγ. These structural data provide significant insights into molecular basis of PLRS caused by V290M mutation and are correlated with the receptor disability of rosiglitazone binding and increased affinity for corepressors. Furthermore, our structural evidence helps to explain clinical observations which point out to a failure to restore receptor function by the treatment with a full agonist of PPARγ...
The transactivation properties of the two estrogen receptors, ERalpha and ERbeta, were examined with different ligands in the context of an estrogen response element and an AP1 element. ERalpha and ERbeta were shown to signal in opposite... more
The transactivation properties of the two estrogen receptors, ERalpha and ERbeta, were examined with different ligands in the context of an estrogen response element and an AP1 element. ERalpha and ERbeta were shown to signal in opposite ways when complexed with the natural hormone estradiol from an AP1 site: with ERalpha, 17beta-estradiol activated transcription, whereas with ERbeta, 17beta-estradiol inhibited transcription. Moreover, the antiestrogens tamoxifen, raloxifene, and Imperial Chemical Industries 164384 were potent transcriptional activators with ERbeta at an AP1 site. Thus, the two ERs signal in different ways depending on ligand and response element. This suggests that ERalpha and ERbeta may play different roles in gene regulation.