Search results for "transactivation"
showing 10 items of 54 documents
The induction of cytochrome P450 3A5 (CYP3A5) in the human liver and intestine is mediated by the xenobiotic sensors pregnane X receptor (PXR) and co…
2004
Induction of cytochrome P450 3A (CYP3A) by xenobiotics may lead to clinically relevant drug interactions. In contrast with other CYP3A family members, studies on the inducibility of CYP3A5 indicate conflicting results. We report the induction of CYP3A5 mRNA in 13 of 16 hepatocyte preparations exposed to rifampin. Furthermore, induction of CYP3A5 mRNA was observed in intestinal biopsies in three of eight probands following exposure to the antibiotic. The highest absolute levels of CYP3A5 transcripts were found following rifampin treatment in hepatocytes and intestines from carriers of CYP3A5*1 alleles. Elucidation of the mechanism involved in CYP3A5 induction revealed that constitutively act…
A Functional Role of IκB-ε in Endothelial Cell Activation
2000
Abstract The NF-κB inhibitor IκB-ε is a new member of the IκB protein family, but its functional role in regulating NF-κB-mediated induction of adhesion molecule expression is unknown. In vascular endothelial cells, IκB-ε associates predominantly with the NF-κB subunit Rel A and to a lesser extent with c-Rel, whereas IκB-α and IκB-β associate with Rel A only. Following stimulation with TNF-α, pyrrolidine dithiocarbamate (PDTC), N-acetylcysteine, and dexamethasone prevented IκB kinase-induced IκB-α, but not IκB-β or IκB-ε phosphorylation and degradation. Since the activation of NF-κB is required for the induction of adhesion molecule expression, we examined the role of IκB-ε in the transacti…
Detection of Fibroblast Growth Factor Receptor 1 (FGFR1) Transactivation by Muscarinic Acetylcholine Receptors (mAChRs) in Primary Neuronal Hippocamp…
2018
In addition to their canonical intracellular signals involved in the regulation of neuronal plasticity, G-protein coupled receptors can also rapidly transactivate tyrosine kinase receptors and their downstream intracellular signaling in absence of specific ligands. Here we describe our protocol for dissociating and maintaining hippocampal primary neurons in high- and low-density culture, followed by a description of methods employed to evaluate neurite outgrowth and protein phosphorylation associated with fibroblast growth factor receptor 1 transactivation by muscarinic acetylcholine receptors. Our goal was to provide the reader with detailed protocols of the abovementioned techniques and t…
A compound-based proteomic approach discloses 15-ketoatractyligenin methyl ester as a new PPARγ partial agonist with anti-proliferative ability
2017
AbstractProteomics based approaches are emerging as useful tools to identify the targets of bioactive compounds and elucidate their molecular mechanisms of action. Here, we applied a chemical proteomic strategy to identify the peroxisome proliferator-activated receptor γ (PPARγ) as a molecular target of the pro-apoptotic agent 15-ketoatractyligenin methyl ester (compound 1). We demonstrated that compound 1 interacts with PPARγ, forms a covalent bond with the thiol group of C285 and occupies the sub-pocket between helix H3 and the β-sheet of the ligand-binding domain (LBD) of the receptor by Surface Plasmon Resonance (SPR), mass spectrometry-based studies and docking experiments. 1 displayed…
Role of SIRT1 and FOXO factors in eNOS transcriptional activation by resveratrol.
2013
Many of the cardiovascular protective effects of resveratrol are attributable to an enhanced production of nitric oxide (NO) by the endothelial NO synthase (eNOS). Resveratrol has been shown to enhance eNOS gene expression as well as eNOS enzymatic activity. The aim of the present study was to analyze the molecular mechanisms of eNOS transcriptional activation by resveratrol. Treatment of human EA.hy 926 endothelial cells with resveratrol led to a concentration-dependent upregulation of eNOS expression. In luciferase reporter gene assay, resveratrol enhanced the activity of human eNOS promoter fragments (3500, 1600, 633 and 263bp in length, respectively), indicating that the proximal promot…
Transactivation of cellular genes involved in nucleotide metabolism by the regulatory IE1 protein of murine cytomegalovirus is not critical for viral…
2008
ABSTRACT Despite its high coding capacity, murine CMV (mCMV) does not encode functional enzymes for nucleotide biosynthesis. It thus depends on cellular enzymes, such as ribonucleotide reductase (RNR) and thymidylate synthase (TS), to be supplied with deoxynucleoside triphosphates (dNTPs) for its DNA replication. Viral transactivation of these cellular genes in quiescent cells of host tissues is therefore a parameter of viral fitness relevant to pathogenicity. Previous work has shown that the IE1, but not the IE3, protein of mCMV transactivates RNR and TS gene promoters and has revealed an in vivo attenuation of the mutant virus mCMV-ΔIE1. It was attractive to propose the hypothesis that la…
Role of reactive oxygen species in the regulation of HIF-1 by prolyl hydroxylase 2 under mild hypoxia
2012
The function and survival of eukaryotic cells depends on a constant and sufficient oxygen supply. Cells recognize and respond to hypoxia by accumulation of the transcription factor hypoxia-inducible factor 1 (HIF-1), composed of an oxygen-sensitive HIF-1α and a constitutive HIF-1β subunit. Besides physiology, HIF-1 induction is involved in major pathological processes such as cardiovascular disease, inflammation and cancer, which are associated with the formation of reactive oxygen species (ROS). ROS have been reported to affect HIF-1 activity but the role for ROS in regulating HIF-1 has not been definitely settled. In order to shed light on the redox-regulation of HIF-1 by ROS, we studied …
Differential Regulation of CCL22 Gene Expression in Murine Dendritic Cells and B Cells
2005
Abstract The activated T cell-attracting CC chemokine CCL22 is expressed by stimulated B cells and mature dendritic cells (DC). We have cloned and sequenced the complete mouse gene, including 4 kb of the 5′-flanking promoter region, and detected two distinct sites for initiation of transcription by 5′-RACE. Reporter gene assays indicate that the promoter reflects the specificity of the endogenous gene. Within the proximal promoter region, we identified potential binding sites for NF-κB, Ikaros, and a putative GC box. All three regions bind proteins. The NF-κB site was shown to specifically bind NF-κB subunits p50 and p65 from nuclear extracts of LPS-stimulated B cells, B cell line A20/2J, T…
Increased AICD generation does not result in increased nuclear translocation or activation of target gene transcription.
2008
A sequence of amyloid precursor protein (APP) cleavages culminates in the sequential release of the APP intracellular domain (AICD) and the amyloid beta peptide (Abeta) and/or p3 fragment. One of the environmental factors favouring the accumulation of AICD appears to be a rise in intracellular pH. Here we further identified the metabolism and subcellular localization of artificially expressed constructs under such conditions. We also co-examined the mechanistic lead up to the AICD accumulation and explored possible significances for its increased expression. We found that most of the AICD generated under pH neutralized conditions is likely cleaved from C83. While the AICD surplus was unable…
The Wilms' tumor suppressor gene (wt1) product regulates Dax-1 gene expression during gonadal differentiation.
1999
Gonadal differentiation is dependent upon a molecular cascade responsible for ovarian or testicular development from the bipotential gonadal ridge. Genetic analysis has implicated a number of gene products essential for this process, which include Sry, WT1, SF-1, and DAX-1. We have sought to better define the role of WT1 in this process by identifying downstream targets of WT1 during normal gonadal development. We have noticed that in the developing murine gonadal ridge, wt1 expression precedes expression of Dax-1, a nuclear receptor gene. We document here that the spatial distribution profiles of both proteins in the developing gonad overlap. We also demonstrate that WT1 can activate the D…