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Parasitic protease SmCB2 as a target for the treatment of schistosomiasis
Bakardjieva, Marina ; Mareš, Michael (advisor) ; Mikeš, Libor (referee)
Blood flukes of the genus Schistosoma are parasitic trematodes that cause schistosomiasis, a serious disease afflicting more than 240 million people. The proteolytic system of schistosomes is essential for their viability: it participates in important processes during host-parasite interactions such as food digestion, invasion and tissue migration. Thus, schistosomal proteases are promising molecular targets for therapeutic intervention in schistosomiasis treatment. The thesis focuses on the protease cathepsin B2 from S. mansoni (SmCB2) which has not been studied in detail so far in terms of biochemical properties and biological function. Recombinant SmCB2 was prepared using yeast and bacterial expression systems and was chromatographically purified. Using an in vitro activity assay, the first effective inhibitors of SmCB2 were identified which inhibited its proteolytic activity in submicromolar concentrations. Specific polyclonal antibodies against SmCB2 were prepared and used for immunomicroscopic localization of this protease on the surface of the parasite. ELISA analysis demonstrated that SmCB2 is a parasite antigen recognized by the host immune system in the mouse model of schistosomiasis. The thesis provides valuable information about SmCB2 as a potential target molecule for synthetic...
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Preparation and biochemical characterization of protease inhibitor equistatin
Polatová, Daniela ; Mareš, Michael (advisor) ; Bořek Dohalská, Lucie (referee)
Equistatin from the sea anemone Actinia equina contains a protein domain Eqd2 which inhibits aspartic peptidases and has not been characterized in detail. Recombinant Eqd2 was produced in the yeast expression system, and a protocol for its chromatographic purification was designed. The inhibitory specificity of Eqd2 was determined using a fluorescence inhibition assay, showing that Eqd2 is a highly selective inhibitor of cathepsin D-like and pepsin-like aspartic peptidases of family A1. Furthermore, size exclusion chromatography was used to analyze the Eqd2-peptidase complex and Eqd2 oligomerization in solution. Initial screening of crystallization conditions for Eqd2 was performed towards its structural analysis. This work provides important new information about Eqd2 as a unique type of natural inhibitors of aspartic peptidases. Its interaction mechanism can be exploited in the development of synthetic mimetics for regulation of medically important peptidases. (In Czech) Key words: peptidase inhibitors, proteolytic enzymes, activity and inhibition of enzymes, recombinant expression, protein purification, protein crystallization, equistatin
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The expression profile of cathepsin L in developmental stages of Fascioloides magna
Šašková, Romana ; Kašný, Martin (advisor) ; Mareš, Michael (referee)
Our experimental organism Fascioloides magna is a digenetic liver fluke from Fasciolidae family which parasitizes in domestic and free-living ruminants of North America and Central Europe including Czech Republic. In Czech Republic this highly pathogenic worm causes a severe liver damage to cervids and bovids and the prevalence locally reaches up to 95%. The biology of F. magna including e.g. the characteristics of host-parasite molecular interaction and the functions of particular molecules produced by the parasite are not fully understood. According to results of our previous research the excretory-secretory products of F. magna adults contain number of molecules which play the crucial role in host tissue invasion, digestion and evasion of the host immune response. One of the most abundant is cysteine peptidase cathepsin L (FmCL). FmCL is supposed to play various key roles in biological processes of all stages during a life cycle and therefore we can suppose its different expression level in particular life stages. In order to define the expression level of FmCL we performed the pilot study with miracidia and adults where the qPCR method was applied. The results of this experiment revealed much higher expression level of FmCL1 in adults than in miracidia. The attempt to in situ localize the mRNA...
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Proteolytic system of blood flukes of the genus Schistosoma
Bakardjieva, Marina ; Mareš, Michael (advisor) ; Dvořák, Jan (referee)
Blood flukes of the genus Schistosoma are parasitic trematodes causing a disease called schistosomiasis, which afflicts more than 200 million people in the tropics and subtropics. Adult schistosomes live in human blood vessels and feed on blood. Critical nutrients required for growth, development and reproduction of schistosomes are obtained from the major blood protein haemoglobin. Its digestion is mediated by the proteolytic arsenal of the schistosome digestive tract, which includes enzymes with complementary specificity belonging to the classes of cysteine and aspartic proteases, and metalloproteases. Proteolytic enzymes also play an important role in other processes, such as host penetration, tissue migration, immune evasion and modulation of inflammation. Here, serine and cysteine proteases importantly participate. The proteolytic system is essential for the viability of schistosomes and is a current topic of intense research focused on the development of new vaccines and chemotherapeutics for the treatment of schistosomiasis. Powered by TCPDF (www.tcpdf.org)
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Structural and functional analysis of cathepsin B1 from the blood fluke, Schistosoma mansoni
Jílková, Adéla ; Mareš, Michael (advisor) ; Obšil, Tomáš (referee) ; Mikeš, Libor (referee)
Schistosomiasis is a serious infectious disease that afflicts over 200 million people in tropical and subtropical regions. It is caused by Schistosoma blood flukes that live in human blood vessels and obtain nutrients from host hemoglobin, which is degraded by digestive proteases. Current therapy relies on a single drug and concern over resistance necessitates new drug development. In Schistosoma mansoni, cathepsin B1 (SmCB1) is a critical digestive protease that is a target molecule for therapeutic interventions. This thesis provides a comprehensive characterization of SmCB1 focused on structure-activity relationships and inhibitory regulation based on six crystal structures solved for SmCB1 molecular forms and complexes. SmCB1 is biosynthesized as an inactive zymogen in which the N-terminal propeptide operates as a natural intra-molecular inhibitor by blocking the active site. Detailed biochemical and structural analyses have identified a new and, so far, unique mechanism of SmCB1 zymogen activation through which the propeptide is proteolytically removed and the regulatory role of glycosaminoglycans in this process has been described. A study of SmCB1 proteolytic activity has revealed that the enzyme acts in two modes, as endopeptidase and exopeptidase, which makes it an efficient tool for host...
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Specific prion protein antibodies characterisation and use in diagnostic
Šafaříková, Eva ; Holada, Karel (advisor) ; Mareš, Michael (referee) ; Živný, Jan (referee)
Transmissive spongiform encephalopathies (TSEs) are neurodegenerative diseases characterized by depositions of abnormally folded prion protein (PrPTSE ) in brain. PrPTSE is at present the only specific biochemical marker of human and animal TSEs. Diagnostic tests are based on the detection of PrPres after proteinase K digestion of brain homogenate using Western blot or on the immunohistochemistry of fixed brain tissue, which are both difficult and time consuming. In this work we focused on development of a new type of tests based on PrP detection without need of proteinase K digestion. As deposits of PrPTSE remain in the body for a long time, there is a substantial chance of them being nonenzymatically modified by glycation. The detection of glycated PrPTSE may have a potential to serve as a diagnostic marker. We prepared monoclonal antibodies specific for carboxymethyl lysine/arginine modified prion protein. Bacterially expressed and purified recombinant human prion protein (rhPrP) was modified by glyoxylic acid that introduces carboxymethyl groups on lysine and arginine residues present within the molecule of the protein. Modified rhPrP (rhPrP-CML) was used for immunization of laboratory mice and hybridoma cells were prepared. Screening of cell supernatants resulted in the selection of 4...
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Media
Mareš, Michael ; Zamazal, Ondřej (advisor) ; Kraus, Jiří (referee)
Diploma thesis "Media as an Agent of National Self-Confidence: Analysis of the Victory of the Czechoslovak Ice Hockey Players at the 1947 World Championship" deals with the reflection of the major sport event in the Czechoslovak media and how this reflection inspired the audience. The goal of this diploma thesis is to describe the dependance between the media coverage and the national self-confidence, which results from the national identity. Therefore, I focused on the chosen newspaper titles to analyze the content they produced during the 1947 Ice Hockey World Championship. I defined a hypothesis, based on observation and scholarly literature, that the media used the coverage to strengthen the national self-confidence and redefine the national identity. My second hypothesis was the idea, that this kind of coverage led to an active response among the audience. Before I started analyzing the three chosen titles (Lidova demokracie, Rude Pravo, Prace), I delivered complex structure of theoretical concepts, describing the influence media have towards the audience and also reasons why the members of the audience use media in their everyday life. I also focused on the historical and political context, as well as the media landscape that shaped the content of that time. I conducted the analysis and...
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Regulation of Cathepsin D Activity and Activation
Máša, Martin ; Mareš, Michael (advisor) ; Jonáková, Věra (referee) ; Holada, Karel (referee)
PhD Thesis ABSTRACT REGULATION OF CATHEPSIN D ACTIVITY AND ACTIVATION Martin Máša supervisor: Michael Mareš Department of Biochemistry Faculty of Science Charles University Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic PRAGUE 2009 Introduction Cathepsin D (CD) is an aspartic peptidase located in the lysosomes of all mammalian cells, its main role is catabolic degradation of proteins. More over CD is known to participate in a range of physiological processes such as apoptosis and tissue homeostasis, as well as in the regulation of angiogenesis and the production of peptidic antigens. The role of CD in pathophysiology is associated with several diseases such as Alzheimer's disease and cancer. Alzheimer's disease is a neurodegenerative disorder, which is generally considered to be the most common form of dementia. Progression of this disease is accompanied with the deposition of amyloid plaques (AP) in the brain, which leads to neurodegeneration. The AP is a fragment released from amyloid precursor protein (APP) cleaved by secretases1 . High levels of CD were found in cerebrospinal fluid of the Alzheimer's patients2 . It was demonstrated that CD is able to cleave APP and produce the pathogenic AP. A genetic polymorphism in the CD gene was reported, which changes...
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