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Characterization and modulation of MitoTam-induced cell death in breast carcinoma cells
Hrysiuk, Mariia ; Anděra, Ladislav (advisor) ; Dráber, Peter (referee)
Although recent years brought many breakthrough discoveries in anti-cancer research and therapy, malignant diseases such as breast cancer (BC) still present one of the major health threats worldwide. Cancer cells usually gain resistance to the activation of regulated cell death (RCD) modalities such as caspase-dependent apoptosis. Among novel RCD-inducing agents belongs to mitochondria-targeted tamoxifen - MitoTam, which is also the major focus of this Thesis. In a panel of BC cells, we determined the energetic (mitochondrial respiration vs. glycolysis) and major RCD-related proteins (Western blotting) profiles, and using Lumascope LS720-assisted time-lapse monitoring we analyzed their sensitivity to MitoTam-induced RCD. We found out that glycolysis-preferring BC cells as MDA-MB-231 are more resistant to MitoTam treatment than mitochondrial respiration-biased MDA-MB-453 cells. However,the majority of tested BC cells can be sensitized to MitoTam by BH3 mimetics such as BCL-XL targeting A1155463 and some cellular metabolism-modulating compounds such as lactate dehydrogenase inhibitor (R)-GNE-140, especially in the pre-treatment regime. Also, other metabolism-modulating compounds such as Pyruvate Dehydrogenase Kinases inhibitor JX06 potently enhanced the efficacy and kinetics of MitoTam-induced RCD....
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Targeting IRAK4 kinase in autoimmune diseases and cancer
Synáčková, Alžběta ; Dráber, Peter (advisor) ; Brdička, Tomáš (referee)
Immune system provides host protection against invading pathogens. However, aberrant activation can lead to development of autoimmune diseases or cancer. Understanding the mechanisms of inflammation and immune responses is crucial for treatment of such conditions and reestablishing immune balance. Toll-like receptors and interleukin-1 family receptors are a key component of the innate immune system. Their downstream molecules, MyD88 and IRAK4, are essential for receptor signaling as their deficiency causes host susceptibility to infection. On the other hand, overactivation of this pathway was shown to be able to promote autoimmunity and cancer. The main focus of this text will be to summarize current knowledge about the mechanism of IRAK4 signaling and how it can be exploited in the development of therapeutics. Keywords IRAK4, MyD88, Toll-like receptors, IL-1 receptor, cytokines, autoimmunity, cancer
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Mechanisms of signal transduction by leukocyte surface receptors and transmembrane adaptor proteins
Dráber, Peter ; Brdička, Tomáš (advisor) ; Brábek, Jan (referee) ; Konvalinka, Jan (referee)
Mechanisms of signal transduction by leukocyte surface receptors and transmembrane adaptor proteins Mgr. Peter Dráber Abstract The central role in the initiation and maintenance of the adaptive immune response is played by interaction of T cells with antigen presenting cells. Upon recognition of peptide- loaded MHC glycoproteins on the surface of antigen presenting cells by specific T cell, immunological synapse is formed and signaling events are initiated in both cells involved. The signal propagation is regulated by various molecules that can have positive or negative function, or even both, depending on specific circumstances. In this work we focused our attention on three topics all encompassing processes of signal propagation or regulation. First, we extended our understanding of the signaling processes taking place in the immunological synapse by the discovery of a new transmembrane adaptor protein SCIMP expressed on antigen presenting cells. Detailed study of this protein demonstrated that it is a positive regulator of MHCII signaling. Next two projects were focused on T cells. We described the role of another transmembrane adaptor protein termed PRR7 in the regulation of apoptosis and T cell receptor (TCR) mediated signaling in T cells. Finally, we provided evidence that in human T cells CD148...
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The role of mTOR signalling pathway in neural differentiation of stem cells
Šintáková, Kristýna ; Jendelová, Pavla (advisor) ; Dráber, Peter (referee)
Spinal cord injury is a very serious, complex, and life changing injury for which today's medicine still does not have an efficient treatment. It is only possible to mitigate the consequences of this injury and the pathological processes associated with it. Neural stem cell transplantation has immunosuppressive effects in the pathology of spinal cord injury and promotes regeneration. mTOR kinase is a member of the crucial intracellular PI3K/Akt/mTOR signalling pathway, making it a suitable target for therapeutic intervention and immunosuppressants such as rapamycin. mTOR signalling is important for neural stem cells and in the pathology of spinal cord injury. The aim of this study was to investigate the role of the mTOR pathway in differentiation of stem cells into neuronal phenotype. Rapamycin was applied to in vitro culture of neural progenitors. Immunocytochemistry and immunoblotting techniques were used to study the effect of this inhibition on the cell phenotype and on the activity of the mTOR pathway. Using the rat model of spinal cord injury in vivo, immunohistochemistry and immunoblotting techniques were used to evaluate the impact of rapamycin inhibition on the mTOR pathway, autophagy, and cytokine production by cells in the damaged tissue. The results show that the mTOR pathway plays role...
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Regulation of IL-17 receptor complex signaling.
Šemberová, Tereza ; Dráber, Peter (advisor) ; Truksa, Jaroslav (referee)
Inflammatory immune response is essential for maintaining the defense against invading pathogens, although its aberrant activation leads to impaired self tolerance and development of autoimmune pathologies. Interleukin-17A (also known as IL-17), is a major proinflammatory cytokine, which contributes to the development and maintenance of inflammation and provides protection against several bacterial and yeast infections. However, extreme activation of IL-17 signaling leads to autoimmune pathologies. Thus, a strict regulation of IL-17 signal transduction is crucial to prevent progression of autoimmunity. Non-degradative ubiquitination is one of the main mechanisms regulating IL-17 signaling. Main E3 ubiquitin ligase within this signal transduction is TRAF6, which is also participating in several signaling pathways within the immune system. Non-degradative polyubiquitin chains created within inflammatory signaling complexes recruit signaling proteins such as IKK complex and TAK1 kinase, crucial for triggering of NF-κB and MAPKs downstream pathways. However, activation of these pathways upon IL-17 is very weak in comparison with other inflammatory stimuli, indicating a presence of a strong negative feedback loop. In this thesis, we establish the role of several regulatory molecules in IL-17 signaling....
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The role of ERK1 and ERK2 protein kinases in the MAPK/ERK signaling
Galvánková, Kristína ; Vomastek, Tomáš (advisor) ; Dráber, Peter (referee)
The MAPK/ERK cascade is highly conserved signalling pathway regulating cellular processes which are necessary for cell life, such as proliferation, differentiation, apoptosis or cell migration. All these cellular responses are the result of the processing of extracellular signals through three-tier ERK cascade consisting of protein kinases Raf, MEK and ERK. The signal is transmitted by sequential phosphorylation where RAF phosphorylates MEK and MEK phosphorylates and activates ERK. Protein kinase ERK then phosphorylates and regulates a wide range of substrates at different locations in the cell. This affects the cellular response to the extracellular signal. Regulation of this pathway on every level is very important and is modulated by interaction partners and adaptor proteins. Deregulation of the pathway as well as mutations of individual protein kinases can lead to severe pathological consequences. At the level of ERK, there are two isoforms, ERK1 and ERK2, which are more than 80 % identical at the amino acid level. Their high sequence similarity has triggered the interest of many authors for more detailed examination of both isoforms in respect of their evolutionary conservation and whether they are functionally redundant or whether they have specific functions. The aim of this work is to...
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Development of an opsonophagocytic assay for the measurement of functional antibody activity against Bordetella pertussis
Brázdilová, Ludmila ; Bumba, Ladislav (advisor) ; Dráber, Peter (referee)
The Gram-negative pathogen bacterium Bordetella pertussis is the infectious agent causing pertussis or whooping cough. The infection is dangerous to infants, often being deadly if untreated. Since whole-cell pertussis vaccines have been replaced by acellular pertussis vaccines, pertussis has become the most prevalent vaccine-preventable disease in developed countries. Therefore, the development of a new generation of pertussis vaccines has become a high priority. Opsonophagocytic assays are one method used to assess the efficacy of new vaccines. The main objective of the thesis is to develop opsonophagocytic killing and uptake assays for the measurement of functional antibody activity against Bordetella pertussis. Neutrophils from mice and humans were isolated by three different methods and used for the assessment of different human and mouse sera in opsonophagocytic killing and uptake assays. Different experimental conditions were tested, including multiplicity of infection and serum dilutions. The opsonophagocytic uptake assay proved to discriminate between naïve and immune sera. Serum from mice vaccinated with the whole-cell pertussis vaccine enhanced opsonophagocytic uptake of B. pertussis cells into neutrophils, while serum from mice immunized with the acellular pertussis vaccine did not....
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Epigenetic Aspects of normal and malignant hematopoiesis: role of chromatin remodeling ISWIATPase.
Zikmund, Tomáš ; Stopka, Tomáš (advisor) ; Dráber, Peter (referee) ; Otáhal, Pavel (referee)
Chromatin remodeling protein Smarca5 participates on many cellular processes, which are important for tissue development and tumorigenesis. Among these processes utilizing ATPase activity of Smarca5 belong also transcription, replication and DNA repair. We hypothesized that Smarca5 represents essential molecule for chromatin modulation primarily at early developmental stages at the level of fast-dividing progenitors of many origins, in whose the ATPase is highly expressed. To such tissues may belong also hematopoiesis, in which the Smarca5 has highest expression. The subject of my doctoral thesis is therefore analysis of the effect Smarca5 depletion on proliferation and differentiation of hematopoietic progenitors in vivo and a search for mechanisms behind the resulted developmental defects. We utilized conditionally knockout allele of Smarca5 in blood precursors to study in a mouse model how depletion of the ISWI ATPase causes accumulation of earliest progenitors inhibited from further maturation to erythroid and other myeloid lines. The proerythroblasts became dysplastic and the majority of basophilic erythroblasts ceased cycling around the G2/M stage. An expected mechanism for observed changes appeared the activation of stress pathway of protein p53 that is often associated with unrepaired DNA...
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Assembly and signaling of IL-17 receptor complex.
Šemberová, Tereza ; Dráber, Peter (advisor) ; Černý, Jan (referee)
Interleukin-17 is a proinflammatory cytokine that contributes to the host protection through initiation and amplification of inflammation. Inflammation is a crucial mechanism of immune system which protects host from invading pathogens and toxic agents. However, uncontrolled activation of the immune system may also promote autoimmune chronic diseases. Due to this, understanding how proinflammatory signaling pathways are activated and propagated is important in order to prevent autoimmune and chronic inflammatory disorders. This text will discuss molecular mechanisms of interleukin-17 signal pathway leading to the progression of inflammatory immune responses with focus on activators and inhibitors of proximal interleukin-17 receptor signaling. Keywords Interleukin-17, proinflammatory cytokines, signal transduction, receptor signaling complex, autoimmune disorders, inflammation
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