|
|
Endocrine disruptors as ligands of nuclear receptors.
Tóthová, Veronika ; Pávek, Petr (advisor) ; Jirkovský, Eduard (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Veronika Tóthová Supervisor: prof. PharmDr. Petr Pávek, Ph.D. Title of diploma thesis: Endocrine disruptors as ligands of nuclear receptors Endocrine disruptors are synthetic substances used in many areas of industry or agriculture that negatively affect and interfere with the functions of the endocrine system. Their negative effects have been mentioned since the beginning of the 20th century, but only recently have more attention been paid to them due to their adverse effects on the human organism and the environment. In the thesis, we summarized the mechanisms of action of the most well-known endocrine disruptors on selected nuclear receptors. Specifically, it was bisphenol A and phthalate-type compounds. From nuclear receptors, we focused on PPAR (Peroxisome Proliferator-Activated Receptors), Pregnane X receptor (PXR) and Aryl androstane receptor (AHR). From the information obtained, it follows that we are in constant contact with these substances, and therefore we should devote more attention to studying their effects, because not all mechanisms of action and effects of these compounds are completely known. In this way, we could increase the safety of using these substances,...
|
|
|
A role of microRNAs in the regulation of hepatic drug-metabolizing enzymes
Sedlmajer, Štěpán ; Smutný, Tomáš (advisor) ; Matoušková, Petra (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Štěpán Sedlmajer Supervisor: PharmDr. Tomáš Smutný, Ph.D. Title of diploma thesis: A role of microRNAs in the regulation of hepatic drug-metabolizing enzymes The liver is the main biotransformation organ in the body. Cytochromes P450 and conjugation enzymes are essential enzymes in the metabolism of drugs and other xenobiotics. Recently, there is growing evidence of post-transcriptional regulation of these enzymes through microRNA molecules. MicroRNAs are epigenetic regulators of expression, which usually bind to fully or partially complementary sequences within the 3'UTR (3' untranslated) regions of mRNA molecules. MicroRNAs have a role in interindividual variability of expression and activity of metabolic enzymes. Understanding their role and mechanisms of action may contribute to the development of new drugs and tailored pharmacotherapy. The work summarizes current selected achievements in the research on regulation of mainly hepatic cytochromes P450 and conjugation enzymes through microRNAs. The impact of RNA editing, single nucleotide polymorphisms and pseudogenes is also described.
|
|
|
Development of novel Constitutive androstane receptor (CAR) ligands
Dušek, Jan ; Pávek, Petr (advisor) ; Hudeček, Jiří (referee) ; Chládek, Jaroslav (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Candidate Mgr. Jan Dušek Supervisor Prof. PharmDr. Petr Pávek, Ph.D. Title of Doctoral Thesis Development of novel Constitutive androstane receptor (CAR) ligands Constitutive androstane receptor is nowadays known as the established nuclear receptor that regulates the expression of several key cytochrome P450 enzymes, predominantly CYP3A4 and CYP2B6. Recently it has been shown that CAR has also essential role in the regulation of endogenous metabolism of glucose, lipids, cholesterole or bile acids. Simultaneously, this receptor is considered to have proliferative effect on human hepatocytes and protective effects against toxic and dietary damage of liver parenchyme. Given the possible therapeutic utilization of CAR, its therapeutic options are being intensively studied. Unfortunately, currently known ligands of human or mouse CAR are either poorly selective or indirect. The aim of my doctoral thesis was to find new ligands of mouse and human CAR, that would enable more detailed study of the receptor.
|
|
|
Bioinformatic aspects of nuclear receptors in pharmacotherapy
Škoda, Josef ; Pávek, Petr (advisor) ; Kollár, Peter (referee) ; Matoušková, Petra (referee)
IN ENGLISH LANGUAGE Candidate: Mgr. Josef Škoda Supervisor: Prof. PharmDr. Petr Pávek, PhD. Title of the doctoral thesis: Bioinformatical aspects of nuclear receptors in pharmacotherapy The liver plays a central role in energy homeostasis via processing post-prandial excess energy into storage molecules and reusing stored energy via gluconeogenesis during the fasting period. This tight energy balance is maintained by a myriad of regulating processes. Dysfunction of metabolic control is a key event of severe diseases in today's population, starting with obesity, insulin resistance, and metabolic syndrome, proceeding to end-stage complications in type 2 diabetes, whole organ malfunctions, or even tumor diseases. Master players in metabolic regulation are nuclear receptors (NR) activated by endogenous stimuli or scavenging for nutritional or toxicological signals. NRs regulate gene transcription activation and therefore maintain liver metabolic plasticity. In this thesis, modern molecular biology approaches were used to study ligands of NRs and the effects of their treatment. After the typical activation of a NR, hundreds of genes are regulated, which is beyond the ability to study with conventional biology methods. For this purpose, omics methods are an ideal solution. They are characterized by...
|
|
|
Interactions of resveratrol derivatives with PXR receptor
Marešová, Veronika ; Pávek, Petr (advisor) ; Trejtnar, František (referee)
Charles University in Prague Department of Pharmacology & Toxicology Student: Supervisor: Prof Title of diploma thesis: Interactions of resveratrol derivatives with PXR receptor Derivatives of resveratrol belong between natural substances contained mainly in red wine and grapefruit. These compounds with stilbene-like structure show antioxidant activity. Pregnane X receptor (PXR) regulates expression of the most important biotransformation enzymes in human liver and intestine including cytochrome P450 3A4 (CYP3A4). Interaction of resveratrol and PXR have already been studied, but published data are contradictory. In my diploma thesis, I studied interaction of resveratrol and its derivatives with PXR. For this purpose, gene reporter assay with quantitative real-time polymerase chain reaction (qRT-PCR) was introduced. It was not possible to conduct experiments in standard way because both resveratrol and its derivatives inhibit lusiferase activities. I studied also effects of resveratrol and its derivatives on expression of CYP3A4 mRNA on differentiated HepaRG cell line. New method gene reporter method with qRT-PCR detection of luciferase was established on hepatoma cell line HepG2 transfected with CYP3A4 reporter construct. Concertation dependent effects of resveratrol and its derivatives were...
|
|
|
Molecular mechanisms of interactions- interactions of constitutive androstane receptor with selected stilbene compounds
Linhartová, Lenka ; Pávek, Petr (advisor) ; Smutná, Lucie (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Lenka Linhartová Supervisor: Prof. PharmDr. Petr Pávek, Ph.D. Title of diploma thesis: Molecular mechanisms of intractions - interactions of constitutive androstane receptor with selected stilbene compounds Constitutive androstane receptor (CAR), member of nuclear receptors family, is a major regulator of gene expression of phase I and II enzymes metabolizing endobiotics and xenobiotics. Changes in its activity can lead to pharmacokinetic drug interactions, ineffective treatment or higher toxicity of drugs simultaneously administered with CAR ligands. Recently another effects of this receptor, especially in homeostasis of bile acids, lipids and glucose have been discovered and CAR is now considered as a potential drug target for the treatment of metabolic diseases. Stilbenes represent a small group of plant polyphenols with typical 1,2-diphenylethylene nucleus. The most famous member is resveratrol, which has attracted great attention thanks to its antioxidant, anti-inflammatory, antiproliferative and cardioprotective effects. Others stilbene compounds such as pterostilben, piceatannol or pinosylvin have shown similar health beneficial effects as well. The aim of this diploma thesis was...
|
|
|
Gene expression regulation by nuclear receptors in a specific metabolic context - evolutionary perspective
Kaššák, Filip ; Kostrouch, Zdeněk (advisor) ; Macůrková, Marie (referee) ; Leontovyč, Ivan (referee)
In animals, some of the most critical regulators of gene expression are nuclear hormone receptors (NRs) and their coregulators, specifically the Mediator complex. Of particular interest are the NRs implicated in metabolic and developmental regulation and in carcinogenesis: thyroid hormone receptors (TRs) and retinoid X receptors (RXRs). In this work, I venture to elucidate some aspects of gene expression regulation by these NRs: the degree of evolutionary conservation of signalling based on NRs and their coregulators; the mechanisms of negative regulation by NRs; and possible implications of these findings for clinical medicine. State-of-the-art bioinformatical, genome editing and microscopic techniques are applied at three levels of animal evolution to study NRs and Mediator. Reverse genomics in human patients suffering from the syndrome of resistance to thyroid hormones β are used to infer the structure and function of TRβ subdomains. Alignments, binding studies and in vivo experiments in Trichoplax adhaerens allow identification of a close orthologue of human RXR at the basis of metazoan evolution. Employing database queries, genome editing and microscopy, we describe a correct orthologue of the Mediator subunit 28 in Caenorhabditis elegans, indicating a complete homology of the Mediator complex...
|
|
|
Novel bile acid derivatives as a promising therapeutic approach for liver and metabolic disorders
Štefela, Alžbeta ; Pávek, Petr (advisor) ; Vítek, Libor (referee) ; Juřica, Jan (referee)
IN ENGLISH LANGUAGE Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmacology and Toxicology Candidate: Mgr. Alžbeta Štefela Supervisor: Prof. PharmDr. Petr Pávek, PhD. Title of the doctoral thesis: Novel bile acid derivatives as promising therapeutic approach Bile acids (BAs) are amphipathic steroidal molecules that are traditionally known to facilitate intestinal digestion and absorption of lipids and fat-soluble substances. On top, the recent findings have revealed that they represent important signaling agents involved in the orchestration of lipid, glucose and energy metabolism and immune response. BAs exhibit these roles by activating intracellular nuclear receptors such as farnesoid X (FXR), pregnane X (PXR) vitamin D receptors. Furthermore, BAs act as endocrine signaling molecules and activate numerous biological cascades via a membrane G-protein-coupled receptor, termed TGR5. Therefore, the extensive modulation of BA scaffold underwent to identify compounds with specific targeting of above-mentioned receptors as a promising therapeutic approach for the treatment of various liver and metabolic disorders including cholestasis, biliary cirrhosis, nonalcoholic steatohepatitis or diabetes. The principal aim of this doctoral thesis was to investigate the structure...
|
|
|
Novel bile acid derivatives as a promising therapeutic approach for liver and metabolic disorders
Štefela, Alžbeta ; Pávek, Petr (advisor) ; Vítek, Libor (referee) ; Juřica, Jan (referee)
IN ENGLISH LANGUAGE Charles University, Faculty of Pharmacy in Hradec Králové, Department of Pharmacology and Toxicology Candidate: Mgr. Alžbeta Štefela Supervisor: Prof. PharmDr. Petr Pávek, PhD. Title of the doctoral thesis: Novel bile acid derivatives as promising therapeutic approach Bile acids (BAs) are amphipathic steroidal molecules that are traditionally known to facilitate intestinal digestion and absorption of lipids and fat-soluble substances. On top, the recent findings have revealed that they represent important signaling agents involved in the orchestration of lipid, glucose and energy metabolism and immune response. BAs exhibit these roles by activating intracellular nuclear receptors such as farnesoid X (FXR), pregnane X (PXR) vitamin D receptors. Furthermore, BAs act as endocrine signaling molecules and activate numerous biological cascades via a membrane G-protein-coupled receptor, termed TGR5. Therefore, the extensive modulation of BA scaffold underwent to identify compounds with specific targeting of above-mentioned receptors as a promising therapeutic approach for the treatment of various liver and metabolic disorders including cholestasis, biliary cirrhosis, nonalcoholic steatohepatitis or diabetes. The principal aim of this doctoral thesis was to investigate the structure...
|
|
|
Pharmacological interventions of nuclear receptors in diabettes mellitus
Draský, Jakub ; Pávek, Petr (advisor) ; Bárta, Pavel (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Jakub Draský Supervisor: prof. PharmDr. Petr Pávek, Ph.D. Title of diploma thesis: Pharmacological influence of nuclear receptors in diabetes mellitus therapy Nuclear receptors belong to the superfamily of transcription factors, their main functions include regulating the expression of target genes. In my work I focused mainly on the group of orphan receptors, namely the pregnane X receptor (PXR) and the constitutive androstane receptor (CAR). A common feature of these receptors is their activation by a specific ligand. Both CAR and PXR have an essential function as biological sensors of hydrophobic xenobiotics when they induce enzymes I and II. phase of metabolism. They are also essential in the regulation of gluconeogenesis, insulin response, adipogenesis, cholesterol homeostasis, fatty acids, triglycerides and glycogen. The aim of this experimental work was to introduce a luciferase reporter assay method for two DNA constructs containing the promoter region of the PEPCK and CYP7A1 genes. We used the known agonist rifampicin and the antagonist SPA70 to activate/deactivate PXR. We used CITCO as a CAR receptor agonist. We first verified the functionality of the luciferase reporter gene assay...
|
guest ::
