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In vitro models for studying Syncytin-1-induced fusion of trophoblast cells
Jech, Lukáš ; Trejbalová, Kateřina (advisor) ; Zíková, Martina (referee)
Trophoblast cell fusion is essential for human placenta development. Apart from initiating blastocyst implantation, syncytialization is critical for optimal nutrient and gas exchange between mother and fo- etus. Multicellular syncytia called syncytiotrophoblast covers the surface of the branched structure of chorionic villi, which is in direct contact with maternal blood. Impairment of the syncytialization process leads to insufficient fetal nutrition and severe pregnancy complications. Syncytia formation is induced by the interaction of the surface glycoprotein of retrovital origin, Syncytin-1, with its receptor. Despite the significance of these processes, the details of cell fusion and trophoblast differentiation remain unk- nown. Furthermore, because of its uniqueness, the human placenta cannot be covered by animal models. As a result, research into human placental development, especially Syncytin-1-induced trophoblast cell fusion, is limited to in vitro trophoblast models. These models include primary trophoblast cell cultures and trophoblast cell lines, which can be obtained by immortalizing cell cultures or extracted from trophoblast tumours. Dedifferentiated trophoblast stem cell cultures were also established. The most recent approach, however, involves the direct reprogramming of dermal...
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Methods of isolation of individual subpopulations of neural stem cells
Zelený, Martin ; Zíková, Martina (advisor) ; Vargová, Ingrid (referee)
Stem cells have huge medical potential, but they are not explored enough for the use in medicine yet. Because of that, their further research is important. One group of the stem cells are neural stem cells, which are differentiating into the neural and glial cells in the brain. Neural stem cells are present at the two areas in the adult brain, subventricular zone and subgranular zone of hippocampus. Neural stem cells are not one homogenous population of cells, but rather various subpopulations with different cell expression. In my bachelor thesis I described the methods, which are used in the research of neural stem cell subpopulations. Described methods focused mainly on the isolation and gene expression. Keywords: neural stem cells, neurogenic zones, molecular markers
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Role of Exosomes in the Progression, Diagnosis, and Treatment of Brain Tumors
Vaníková, Lucie ; Zíková, Martina (advisor) ; Lacina, Lukáš (referee)
Recent studies have confirmed the importance of extracellular vesicles, particularly exosomes, in the development of brain tumors. Considerable attention has been paid mainly to the influence of exosomes on biological processes in brain tumors. Exosomes mediate intercellular communication in the tumor microenvironment by transporting biomolecules. Most often they transmit various types of ribonucleic acids, specifically microRNAs, which affect the signalling pathways related to tumour growth in target cells. Thus, exosomes play an important role in tumor cell proliferation and differentiation, metastasis, and tumor resistance to chemotherapy or radiation. Due to their small size, exosomes can cross the blood-brain barrier and thus promote tumor progression. The topic of the bachelor thesis is a summary of the current knowledge on the role of exosomes in brain tumor progression, diagnosis and treatment.
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Cell therapies designed to restore radiation-induced brain injury
Nuriakhmetova, Elina ; Zíková, Martina (advisor) ; Weissová, Romana (referee)
Neural stem cells are undifferentiated cells that are defined by their replication potential and their ability to differentiate into different types of neuronal and glial cells. The adult brain contains two neurogenic zones located in the subventricular zone of the lateral ventricles and in the dentate gyrus of the hippocampus. In both of these zones, neural stem cells produce new neurons. The subject of the bachelor thesis is a summary of current knowledge about neural stem cells and molecular mechanisms underlying changes in neurogenic zones after radiotherapy. At the same time, cell therapies used to minimize damage associated with radiation are discussed.
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Role of DISP3 in malignancy of medulloblastoma cell line
Jarošová, Šárka ; Zíková, Martina (advisor) ; Havránek, Ondřej (referee)
In the search for new genes that are regulated by thyroid hormone, DISP3, a new member of the SSD (sterol-sensing domain) protein family, has been identified. Expression analysis showed that DISP3 is expressed in cells of neural origin, and our previous results indicate that overexpression of this gene affects cell proliferation and differentiation. Oncomine database analysis also showed that DISP3 expression is increased in medulloblastomas, the most common malignancies of the central nervous system in children. The subject of this diploma thesis is studying the effect of increased DISP3 levels on cell apoptosis and cell ability to form a colony. Cell lines derived from medulloblastomas were used in the work. We compared the expression levels of the DISP3 gene in different medulloblastoma lines by quantitative PCR and selected a line with low expression of this gene for further experiments. Some medulloblastoma cell lines can form neurospheres when cultured in serum-free medium. Using quantitative PCR, we compared the expression levels of neural markers in cells cultured both as neurospheres and as adherent cells. By transfecting cells with a plasmid overexpressing DISP3, we prepared cells with increased levels of this gene. We induced apoptosis by radiation at different doses. Apoptosis was...
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The role of the Wnt signaling pathway in the regeneration following ischemic brain injury
Kriška, Ján ; Anděrová, Miroslava (advisor) ; Stuchlík, Aleš (referee) ; Zíková, Martina (referee)
The role of the Wnt signaling pathway in the regeneration following ischemic brain injury Focal cerebral ischemia results in the loss of neural cells, which may cause permanent disability. At the same time, there are precursor cells (neural stem/progenitor cells and NG2 glia) that naturally reside in the postnatal brain and may proliferate and give rise to other cell types. Their fate is to a large extent influenced by morphogens of the Wnt and Shh family. However, the role of these cellular pathways in differentiation of precursor cells is still enigmatic. For this reason, we employed transgenic mice that enabled us to inhibit or hyper-activate the canonical Wnt signaling pathway, or to map the fate of NG2 cells. The induction of ischemia was achieved by the occlusion of the middle cerebral artery. The changes in the differentiation potential were characterized at the mRNA, protein, and functional levels. First, we evaluated neural stem/progenitor cells isolated from neonatal mice under physiological conditions and found out that Wnt signaling promotes neurogenesis and suppresses gliogenesis. Next, we focused on adult mice and detected a smaller impact of Wnt signaling on their differentiation potential. Nonetheless, its effect was more profound after the induction of ischemia, as we identified...
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Important mechanisms of tumorigenesis and their role in chemoresistance of head and neck cancers
Zlámalová, Viktorie ; Šírová, Milada (advisor) ; Zíková, Martina (referee)
Head and neck squamous cell carcinoma (HNSCC) represents the sixth most common malignancy worldwide. Despite improvements in therapeutic outcomes due to advances in surgery, radiotherapy, chemotherapy, and imaging techniques, HNSCC still has high mortality rate. For patients who are not cured with surgery and radiotherapy, there are few effective treatment options. Although HNSCC is heterogeneous in nature, current molecular classification distinguishes only human papilloma virus positive and negative tumors. HNSCC in general are characterized by considerable resistance and high rate of locoregional recurrence. Loss of p53 control pathway and numerous alterations in components of intracellular signaling pathways are consistently observed throughout the majority of HNSCC cases, supporting uncontrolled proliferation. It was proven that common mutations in the HNSCC genome play major role in tumorigenesis as well as in resistance to chemotherapy. The aim of the thesis is to describe the important mechanisms in HNSCC, which are associated with mutations in epidermal growth factor receptor and p53, and those including PI3K/Akt/mTOR and Notch signaling pathways. Association of these pathways with chemoresistance to commonly used drugs and even to advanced targeted therapeutic agents was evidenced by many...
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Molecular subgroups of medulloblastoma: the current consensus
Jarošová, Šárka ; Zíková, Martina (advisor) ; Nedvědová, Tereza (referee)
Medulloblastoma is the most common malignant brain tumor in children. In recent years, there has been a steady improvement in understanding of genetic and molecular heterogeneity of this tumor, that has led to better prognosis and improved targeted therapies. This thesis summarizes recent advances in molecular sub-grouping, and the associated gene mutation and copy number variations in medulloblastoma.
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The role of Disp3 gene in cell proliferation
Ditrychová, Karolína ; Zíková, Martina (advisor) ; Pospíchalová, Vendula (referee)
Dispatched 3 (DISP3), sterol - sensing domain (SSD) - containing protein, is a key focus of our laboratory. It was described as a gene regulated by thyroid hormone and its expression is mainly localized within neural tissue. Our preliminary data suggested increased DISP3 expression in medulloblastoma, a highly common pediatric cerebellar tumour, therefore we wanted to examine DISP3 role in human cancer cells. The aim of this thesis is to perform DISP3 overexpression and downregulation in human medulloblastoma cell lines and in mouse neural progenitors and analyse its effect on cell proliferation and differentiation. For this purpose, we chose DAOY and D341, human medulloblastoma cell lines with low and high expression of DISP3 and mouse multipotent neural progenitor cell line, C 17.2, with low DISP3 expression. We showed, that DISP3 ectopic expression leads to increase in cell proliferation in both DAOY and C 17.2 cells. Next, we examined the ability of C 17.2 cells to differentiate into neurons and astrocytes and observed, that cells overexpressing DISP3 reveal delay in differentiation, what we proved by analysis of cell specific markers. Using CRISPR-Cas9 targeting system, we reduced DISP3 expression within D341 cells and observed decrease in their proliferation. Finally, we analysed cell cycle...
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Rodina proteinů obsahujících sterol-sensing doménu
Ditrychová, Karolína ; Zíková, Martina (advisor) ; Fafílek, Bohumil (referee)
1. Abstract Sterol sensing domain (SSD) is a putative transmembrane region consisting of 5 helices and in few cases it was shown that it interacts with cholesterol. Proteins containing this domain play a role in many cellular pathways connected to cholesterol. It was first described in a study of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA reductase). It is an enzyme playing role in cholesterol biosynthesis and its transcription is regulated by sterol regulatory element binding protein cleavage activating protein (SCAP). HMG-CoA reductase and SCAP were the first proteins where SSD was recognized. After that, other proteins were described; one more protein functioning in cholesterol biosynthesis was described as containing SSD - 7-dehydrocholesterol reductase. Also two proteins playing role in cholesterol endocytosis - Niemann-Pick type C 1 liked 1 - and in its efflux from lysosomes - Niemann-Pick type C 1 - were recognized. Furthermore, proteins playing role in Hedgehog signalling Patched, Patched-related and Dispatched were found as SSD containing structures. In the end, tumour-suppressor gene TRC8 was also recognized as member of SSD family. In this text, structure and function of these proteins is summarized. Key words: sterol sensing domain, Hedgehog signalling pathway, sterol binding protein,...
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