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The role of cholesterol 7alpha-hydroxylase in regulation of cholesterolemia
Cejpková, Monika ; Kovář, Jan (advisor) ; Leníček, Martin (referee)
The aim of the theses is to characterize the mechanism that participate in the regulation of activity of cholesterol 7α-hydroxylase (CYP7A1) - the key enzyme of classical pathway of bile acids synthesis. The function and metabolism of cholesterol and bile acid is described at the beginning. Cholesterol is a substrate for CYP7A1 and bile acids are produced in the reaction catalyzed by the enzyme. The other parth of theses is dedicated to feedback inhibition of CYP7A1 by bile acids and describes particular regulatory pathways involved. The crucial factors for CYP7A1 expression are bile acids response elements (BARE) in the promoter of CYP7A1 gene. Central role is played by farnesoid X receptor activated by bile salts that induces expression of protein called small heterodimer partner (SHP) in the liver. SHP interacts with trancription factors in BARE and inhibits CYP7A1 transcription. In the instestine FXR induces fibroblast growth factor 19 (FGF19) that activates signalling pathways leading to inhibition of CYP7A1 in the liver. The activity of CYP7A1 can be regulated independently of FXR - there is a role for hormones (insulin, glucagon), glucose, activation of proinflammatory cytokines and other nuclear receptors (pregnane X receptor and vitamin D receptor), that participate in protection of the...
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Drop coating deposition Raman spectroscopy of liposomes with different compositions
Antalík, Andrej ; Kočišová, Eva (advisor) ; Holoubek, Aleš (referee)
Method of drop-coating deposition Raman spectroscopy is a special tech- nique that employs deposition of a small droplet of the sample on a hydro- phobic surface with subsequent solvent removal by evaporation. As a result the concentrated material forms a ring at the edge of the droplet. This techni- que has proven to be efficient for liposome studies at low concentrations. We focused on a study of spectral changes and ring formation in phosphatidylcho- line liposomes due to increasing amount of cholesterol. Higher concentration of cholesterol didn't cause significant changes in membrane structure, such as phase transition, however the ring wasn't formed. Second part of this bache- lor thesis concerns with the search for some alternative surface to previously used SpectRIM TM DCDR plates made by Tienta Sciences, Inc. which are no longer available. The polished calcium fluoride glass (CaF2) seems to be the most suitable for the further use from all tested surfaces. Raman signal at the other surfaces was either weak or spectral bands that don't belong to lipid were observed.
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Regulation of cholesterol metabolism in hepatocytes
Ziková, Kateřina ; Vlachová, Miluše (advisor) ; Zlatohlávek, Lukáš (referee)
This thesis summarizes current data about cholesterol metabolism and its regulation in the liver. First part describes cholesterol transport among tissues by lipoproteins. Second part of this work deals with description of metabolic pathways of cholesterol conversion - how the cells obtain and metabolise cholesterol. Almost all cells can synthesize cholesterol or take it up from the circulation. The cells dispose of abundant cholesterol by several mechanisms - they convert cholesterol to cholesteryl esters that can be stored in lipid droplets; they turn cholesterol into oxysterols that can escape easier from the cell; or they export cholesterol through ATP-binding cassette (ABC) transporters. Specialized tissues (adrenal, gonads) transform cholesterol to steroid hormones. However, only the liver can remove cholesterol from the body in physiologically significant amount - it secretes cholesterol into the bile either directly or after conversion to bile acids. Third section deals with regulation of cholesterol metabolism in hepatocyte. Three transcription factors - sterol regulatory element binding protein (SREBP), liver X receptor (LXR), and farnesoid X receptor (FXR) - play the main role in regulation. Their activities are determined by concentration of cellular cholesterol or its metabolites -...
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Effect of cholesterol depletion on signalling cascade initiated with receptors coupled to G protein class Gq/G11
Ostašov, Pavel ; Svoboda, Petr (advisor) ; Teisinger, Jan (referee) ; Hof, Martin (referee)
Membrane domains are an important structure in plasamatic membrane. They concentrate various signaling molecules. Their main structural component is cholesterol and by its removal the membrane domains are disrupted. The aim of our work was to examine the effect of cholesterol depeletion on signaling initiated thyreothropin releasing hormone (TRH). Although its signaling cascade is located within membrane domains the receptor itself is not. We showed that cholesterol depletion by -cyclodextrin caused release of Gq/11 proteins and caveolin 2 from membrane domains. We also discovered that cholesterol depletion decreases potency of TRH to activate G proteins as well as induction of release of intracellular Ca2+ In the last part we investigated the effect of disruption of the cell membrane integrity by cholesterol depletion on thyrotropin-releasing hormone receptor (TRH-R) surface mobility and internalization in HEK293 cells stably expressing TRH-R-eGFP fusion protein. CLSM studies indicated that the internalization of receptor molecules initiated by TRH stimulation was significantly attenuated. The detailed analysis of recovery of TRH-R-eGFP fluorescence in bleached spots of different sizes indicated that cholesterol depletion results in an increase of overall receptor mobility. We suggest that migration of...
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The importance of biosynthetic and catabolic pathway of cholesterol in inflammatory and tumor diseases
Leníček, Martin ; Vítek, Libor (advisor) ; Haluzík, Martin (referee) ; Mareček, Zdeněk (referee)
This thesis focuses on the importance of intermediate products of biosynthetic and catabolic pathway of cholesterol. The aim of the first part of the thesis is mainly to investigate, whether statins (HMG- CoA reductase inhibitors) possess antitumor properties and to compare the differences in antitumor potential of individual statins. The other part of the thesis aims at the utilization of 7α-hydroxycholest-4-en-3-one (C4), a promising marker of cholesterol 7α-monooxygenase (CYP7A1) activity and bile acid malabsorption. We demonstrated antitumor effect of statins on an experimental model of pancreatic cancer. Individual statins, however, differed significantly in their efficacy, depending on their physico-chemical properties. Our data suggests, that the most likely (but not the only) mechanism of antitumor effect of statins is decreased prenylation of signaling proteins, especially Ras protooncogene. We set up a reliable method for measurement of C4, which facilitated our research in CYP7A1 regulation. We demonstrated, that promoter polymorphism -203A>C might affect CYP7A1 activity, that diurnal variability of CYP7A1 activity might be triggered by insulin, and that insulin resistance in patients with non-alcoholic fatty liver disease impedes the feedback regulation of CYP7A1, which may lead to disease...
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Trends in the Consumption of a chosen ATC Group A10AA (inhibitors HMG-CoA reductase) in the period 2005-2015 in the Czech Republic
Freimann, Antonín ; Lešetický, Ondřej (advisor) ; Železo, Eduard (referee)
The thesis deals with trends of drug consumption for the ATC group C10A (HMG-CoA reductase) in the Czech Republic in the years 2005 - 2015. The goal of this work is to analyse the consumption of statins (cholesterol lowering drugs), as well as to analyse the consumption trends (expressed in terms of prescribed daily doses) and subsequently explain the causes of the detected trends. The main method used in this work is the analysis and interpretation of data provided by the State Institute for Drug Control (SUKL). Individual consumption data sets are compared to each other and global trends are inferred based on the obtained results. In the practical part I analyse the consumption for the individual ATC groups according to their increasing lipid-lowering efficacy, according to the pharmaceutical companies involved and according to the experts' recommendations (within the framework of cardiovascular disease treatment). The conclusion of my work shows that the overall drug consumption for the the studied ATC group (given by the DDD/package total) was steadily increasing during the studied period while the consumption expressed in financial units was decreasing (ie. the financial burden on the health system was reduced). The total number of sold packages shows a slight decrease due to the sale of bigger packages with more powerful statins during the studied period.
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Characterization of liposomes as precursors for the preparation of models of cellular membrane using scattering techniques
Gjevik, Alžběta ; Kalina, Michal (referee) ; Mravec, Filip (advisor)
The bachelor thesis presents a cellular membrane design based on lecithin, cholesterol and POPG basis. It summarizes formation mechanisms, optimization techniques and characterization methods of model cellular membranes. It focuses on preparation of liposomes with various lipid compositions as precursors for model membranes preparation and characterization. Small unilamellar liposomes were formed by thin layer evaporation, thin layer rehydration in phosphate buffer and sonication. Size and stability (-potential) of formed liposomes were measured using dynamic light scattering. Successful supported lipid bilayer formation on glass surface by vesicular fusion was tested using the most stable lipid composition. SLB was characterized by Z-scan fluorescence correlation spectroscopy.
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Catering persons with hypercholesterolemia
CHARYPAROVÁ, Ludmila
My bachelor thesis is called ,,Food for people with hypercholesterolemia", and it focuses on cholesterol intake and its impact on the human body. The main aim of this thesis was to map the diet of people with hypercholesterolemia regarding both, quality and quantity of meals. The first part of this thesis is theoretical. It focuses on the description of basic nutritional components, on the issue of fat and cholesterol in the diet, on the characteristics of hypercholesterolemia disease, its classification, causes of development of this disease, treatment options and prognosis. The risk factors which lead to the hypercholesterolemia disease development, dietary restrictions, and some examples of low cholesterol and low fat diet menus are also mentioned in the first part of thesis. The practical part of this thesis was done as a qualitative and quantitative research. Qualitative research was conducted using the snowball method from February to March. Selected respondents recorded their diet for the period of one week. The diet was recorded in the record sheets which I evaluated after they were filled in and returned back to me. I entered all of the foods mentioned in the diet record sheets into the program ,,Nutriservis Prefesional", which helped me to calculate average intake of energy, fats, cholesterol, proteins and carbohydrates during the reference period. I also submitted questionnaire to examine eating habits, diseases and physical parameters of my respondents. The questionnaire was focused mainly on the frequency and quantity of food with high cholesterol. Then I determined the ideal weight according to BMI index for every respondent and from the ideal weight I calculated the ideal intake of calories, fats, proteins and carbohydrates per day. I compared ideal values of energy, macronutrients and cholesterol of each respondent with average values recorded during the research. The research revealed that most respondents have a diet with larger quantities of cholesterol than the recommended daily dose i.e. 300 mg of cholesterol per day.
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Vliv PUFA n-3 na expresi genů kódujících proteiny řídící homeostázu cholesterolu
Hyblerová, Dagmar
The aim of this study was to confirm that the polyunsaturated fatty acids n-3 (n-3 PUFA) have a positive effect on plasma lipids. These acids can reduce cholesterol by increasing gene expression Insig-1 while decreasing the expression of genes encoding Hmgcr and Ldlr. We tested in experimental rats, which were added to the feed mixture of 6 % safflower oil , 6 % fish oil or 6 % of the oil from the algae Schizochytrium. Relative gene expression was Insig-1 in the test group with addition of fish oil to 120% of controls (P<0.05) and in the group with addition of oils from algae Schizochytrium the relative expression of 170 % of control (P<0.05). These results confirm our hypothesis, only a part, as the relative expression of the gene and Hmgcr and Ldlr was in the test group with addition of fish oil 103% (P>0.05) and 101 % of control (P>0.05) and in the group with addition of oils from algae Schizochytrium the relative expression of 117% (P>0.05) and 156 % (P>0.05) compared to control. Thus, to reduce the relative expression of these genes did not. However, we have shown that n-3 PUFA contribute to a reduction in plasma cholesterol and in this case up to 20 % of control. The concentration of cholesterol in the group with addition of safflower oil was 1.35 mmol.l-1, the group with the addition of fish oil 0.98 mmol.l-1.
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