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Leukemic stem cells
Vobořil, Matouš ; Stöckbauer, Petr (advisor) ; Šídová, Monika (referee)
The biology of stem cells came to the foreground not only due to scientific but also due to clinical interest and it is one of the most developing fields of current biomedical research. The idea, that all tumor cells contain population of cells like stem cells, leads to the "cancer stem cells hypothesis". It says, that each tumor cell contains small population of cells capable to initiate and maintain the tumor growth. Tumors of the hematopoietic tissue were the first, where cancer or leukemic stem cells were isolated. Therefore, leukemic stem cells are so far the best understood cancer stem cells. However, despite the huge advances in the biology of leukemic stem cells, there are many properties still unknown. This thesis initially presents basic knowledges in the stem cell biology, including their origin and identification. Later it focuses on the stem cell hypothesis and describes of the main properties of stem cells in solid tumors. The main part of this thesis also shows in details the origin and properties of the leukemic stem cells and decribes some new directions in the targeted therapy of hematological malignancies.
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AIRE-expressing cells in immune tolerance in health and disease
Vobořil, Matouš ; Filipp, Dominik (advisor) ; Černý, Jan (referee) ; Ehrlich, Lauren Ilyse Richie (referee)
The process of self-nonself discrimination by the immune system is a fundamental attribute of healthy organisms. Since T-cell receptors (TCRs) are generated by the random process of somatic recombination without regard to its targets, the newly developed T-cell clones could recognize either self or nonself antigens. The mechanisms of central tolerance robustly limit the self-reactive repertoire within the T-cell population via deletion of clones that express self-reactive TCRs or their deviation into the regulatory T-cells (Tregs). These processes occur mainly in the thymic medulla where the TCR reactivity to self-antigens is tested by various types of antigen-presenting cells, mainly medullary thymic epithelial cells (mTECs), dendritic cells (DCs), and B-cells. The cooperation between these cell-types has been shown to be essential for the establishment of thymic tolerance. A key molecule regulating the production of self-antigens is the autoimmune regulator (AIRE), which is thought to be expressed primarily by mTECs and its mutations are associated with the development of severe autoimmune disorders. In this context, the presented thesis describes the novel regulatory pathways important for the development of a functional and "harmless" repertoire of T-cells and for enforcement of tolerance....
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Antimicrobial properties of mesenchymal stem cells
Černá, Kristýna ; Hájková, Michaela (advisor) ; Vobořil, Matouš (referee)
Mesenchymal stem cells (MSCs) were first isolated from bone marrow. Since that they were isolated from almost every tissue in the body. MSCs are multipotent cells with many properties including self-renewal, differentiation into the cells of all three germ lines, trophic and immunomodulatory abilities, specific migration to the site of injury and recently discovered antimicrobial properties. This properties make them a good candidate for cell therapy because they can be used in treatment of many diseases including bacterial infections. This thesis brings a summary of all discovered antimicrobial properties of MSCs. It is primarily focused on their direct and indirect antimicrobial effect. The direct effect is mediated by a secretion of antimicrobial substances and the indirect effect includes an impact on the activity and functions of macrophages and neutrophils. Extracellular vesicles derived from MSCs constitute separate chapter because they can have both direct and indirect antimicrobial effect. Keywords: mesenchymal stem cells, antibacterial effect, bacteria, antimicrobial peptides
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Aire-expressing cells in immune peripheral tissues
Vobořil, Matouš ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
5 Abstract Tolerance to "self" is the fundamental property of the immune system and its breakdown can lead to autoimmune diseases. In order to eliminate self-reactive T- cells during their development in thymus (central tolerance), Aire promotes the expression of peripheral self-antigens in medullary thymic epithelial cells (mTECs). Recently, Aire was suggested to fulfil a similar function in rare lymph node and spleen cells (peripheral tolerance). However, the detection, characterization and function of these extrathymic Aire-expressing cells is still obscure. The main objective of presented thesis was to investigate if Aire positive cells are also present in other lymphoid as well as non-lymphoid tissues. Using two independent mouse transgenic models we identified the Aire-reporter expressing cells in several lymphoid tissues such as Peyer's patches, spleen and bone marrow as well as in one non-lymphoid organ, the lungs. We show here that based on the expression of B220, EpCAM and CD11c markers these heterogenic cells consist of at least five phenotypically distinct subpopulations, and with the exception of those from lungs, all of them are strictly of hematopoietic origin. This study also demonstrates that Aire on protein level is predominantly expressed by one of these subpopulations with CD45+ MHCII+...
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Leukemic stem cells
Vobořil, Matouš ; Stöckbauer, Petr (advisor) ; Šídová, Monika (referee)
The biology of stem cells came to the foreground not only due to scientific but also due to clinical interest and it is one of the most developing fields of current biomedical research. The idea, that all tumor cells contain population of cells like stem cells, leads to the "cancer stem cells hypothesis". It says, that each tumor cell contains small population of cells capable to initiate and maintain the tumor growth. Tumors of the hematopoietic tissue were the first, where cancer or leukemic stem cells were isolated. Therefore, leukemic stem cells are so far the best understood cancer stem cells. However, despite the huge advances in the biology of leukemic stem cells, there are many properties still unknown. This thesis initially presents basic knowledges in the stem cell biology, including their origin and identification. Later it focuses on the stem cell hypothesis and describes of the main properties of stem cells in solid tumors. The main part of this thesis also shows in details the origin and properties of the leukemic stem cells and decribes some new directions in the targeted therapy of hematological malignancies.
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