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Dipeptidyl peptidase-IV and Fibroblast activation protein in gliomagenesis.
Trylčová, Jana ; Šedo, Aleksi (advisor) ; Mandys, Václav (referee) ; Mareš, Vladislav (referee)
"Dipeptidyl peptidase-IV Activity and/or Structure Homologues"(DASH) represent a newly defined group of multifunctional molecules, typically bearing dipeptidyl peptidase-IV- like hydrolytic activity. Dipeptidyl peptidase-IV (DPP-IV) cleaves out X-Pro dipeptides from the N-terminus of peptides. Other molecules carrying similar enzyme activity, such as Fibroblast activation protein (FAP), DPP-II, DPP8 and DPP9 or even DPP-IV structure-like but hydrolytically inactive molecules (DPP6 and DPP10) also belong to this group. Recent knowledge suggest a substantial role of DASH in cancer pathogenesis. The aim of this study is a preparation of a biological model and its use for understanding the mechanisms of interaction(s) between transformed glial cells and stroma in the processes of origin and development of tumors derived from neuroectoderm. Stable transfected human glioblastoma cell lines with inducible gene expression of DPP-IV, Fibroblast activation protein and their enzymatically inactive mutated forms, were prepared within the project. Prepared cell lines are used as a tool for studying not only the "autocrine" importance of DPP-IV and FAP for the expressing cells in in-vitro, but also for their potential "paracrine" effect(s) within the tumor microenvironment after homotopic implantation into the...
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Structure, activity and metabolism of human glutamate carboxypeptidase II
Mlčochová, Petra ; Konvalinka, Jan (advisor) ; Blahoš, Jaroslav (referee) ; Šedo, Aleksi (referee)
CONCLUSIONS AND PERSPECTIVES Recentry reported crystal sructures of GCpII provide stucturar insight into the organization of the substrate binding cavity and highlight residues implicated in substrate / inhibitor binding in the sI site of the enzyme. To comprement and extend the s[ucturar studies, we constructed a QMzMM model of GCPII in complex with its substrate, N-aceýt. aspartyl-glutamate, which enabled us to pÍedict additional anrino acid residues interacting with the bound subsrate. and used site-directed mutagenesis to assess the contribution of individual residues for substrate ,/ inhibitor binding and enzymatic activity of GCpII. we prepared and characterized 12 GcpJ' mutants targeting the amino acids in the vicinity of substrate./inhibitor binding pockets. The experimental results suggest that residues (especiaily Arg210) in the sť site are critical for substrate./inhibitor binding, whereas the residues forming the sl pocket niight be more important for the .fine-tuning, of GCptr substrate specificity and appear to be relevant for substrate turnover and may play a role in the enzyme's mechanism of action. Even though the QIVýMM calculations of the NAAG binding mode in the GCPII active site enabled us to predict the structure and enzyme-substrate interactions in the sl binding site, the complete...
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Posttranslational modifications in soluble recombinant therapeutical proteins secreted by lower aukaryotes: structure and function
Kumar, Vinay ; Bezouška, Karel (advisor) ; Šedo, Aleksi (referee) ; Grubhoffer, Libor (referee)
Virtat, Kunnr M.Sc Aint of the stud1, Aim of the studv The aim of this study was to understand the molecular mechanisnrs contributing to the production of soluble leukocyte receptors in the eukaryotic expression systenrs including the proper posttranslational modifications such as disulfide bond fornration and glycosylation. In order to achieve this goal, the following specific aims have been adopted for the study: l, t. To develop new methodologies for rapid and convenient assessnrent ofthe disulfide L I boltds in complex eukaryotic proteins using SDS polyacrylarride electrophoresis under nonreducing conditions, arrd nrass spectrometry. 2. To establish elements that are critical for the stability of soluble CD69 receptors expressed in the bacterial expression systenr 3. To develop methods for the production of glycosylated soluble CD69 proteins in lower eukaryotes (P i c h i a pa s to ri s) 4. To purify the proteins in sufficient quantities for biochemical and inrnrunological studies 5. To investigate, how disulfide bonding and glycosylation influeuces the stability of soluble CD69 receptors 6. To look at the carbohydrate binding activities ofthe produced proteins. 7. To evaluate the in vivo propefties of the produced proteins including their circulation half lifes in the blood of experiental animals, and...
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Dipeptidyl peptidase IV in orthotopic models of glioma
Hilšer, Marek ; Šedo, Aleksi (advisor) ; Mandys, Václav (referee) ; Šefc, Luděk (referee)
Malignant gliomas belong to a highly aggressive class of tumours. Average patient survival time generally does not exceed 15 months. Despite intensive research, no therapeutic strategies capable of significantly extending the lives of those affected by the disease have been established to date. One potentially viable area of research into possible therapeutic targets in cancer therapy focuses on cell surface proteases. This group of proteins includes dipeptidyl peptidase IV (DPP-IV). Changes to DPP-IV expression have been established in the case of various cancer types including malignant gliomas. Understanding the role of DPP-IV in the biological processes of this malignant disease may thus contribute to the development of new therapeutic modalities. This thesis is therefore dedicated to establishing an orthotopic xenograft model as well as a genetically engineered model (GEM) of the glioma. The effects of DPP-IV on the growth of an experimental glioma were subsequently examined, as was the ratio of catalytic and non- catalytic mechanisms in this process. The GEM model was used for monitoring enzymatic activity and DPP-IV distribution. Non-invasive fluorescence imaging was employed in order to monitor the intraexperimental dynamics of experimental gliomas. The results indicated that DPP-IV...
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"DASH molecues" in local and systemic pathogenetic processes of rehumatoid arthritis
Šromová, Lucie ; Šedo, Aleksi (advisor) ; Borovanský, Jan (referee) ; Prokešová, Ludmila (referee)
The biological half-life of several pro-inflammatory mediators involved in the pathogenesis of rheumatoid arthritis (RA) is controlled by molecules exhibiting dipeptidyl peptidase-IV (DPP-IV)-like enzymatic activity (Dipeptidyl peptidase-IV activity and/or structure homologues- DASH). The aim of this thesis was to identify the molecular source of the DPP-IV-like enzymatic activity in the peripheral blood and synovial fluid in patients with rheumatoid arthritis as compared to control patients with osteoarthritis (OA), and to evaluate the association of DPP-IV with the disease activity. We found that the main source of the DPP-IV-like enzyme activity in the plasma and in the synovial fluid in patients with RA is the canonical DPP-IV. DPP-IV-like enzymatic activity and canonical DPP-IV were also detected on the cell surface of blood and synovial fluid mononuclear cells. Significantly lower DPP-IV-like enzymatic activity and DPP-IV expression in the synovial fluid mononuclear cells was found in RA as opposed to OA patients. In the synovial fluid of RA patients there was also a negative correlation between the concentration of the pro-inflammatory DPP-IV substrate SDF (stromal cell-derived factor-1 and the proportion of the DPP-IV+ T cells. The blood plasma DPP-IV-like enzymatic activity and...
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