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Induction of testicular stem cell differentiation in mammals.
Strnadová, Karolína ; Tlapáková, Tereza (advisor) ; Krulová, Magdaléna (referee)
Stem cells represent a unique cell source with potential usage in regenerative medicine and organ transplantation. As is known, spermatogonial stem cells are unipotent giving rise to a single cell type, which is sperm. Pluripotency was achieved by isolation and cultivation of these testicular stem cells in a number of researches. Testicular pluripotent stem cells differentiated in conditions in vitro to derivatives of all three germ layers identically as embryonic stem cells. The aim of this thesis is to characterize stem cells and summarize the findings of testicular stem cell research. The main focus of this thesis is on studies of cultivated pluripotent stem cells derived from mouse and human testes and their ability to differentiate under determinate conditions into the cells of ectoderm, mesoderm and endoderm.
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Therapeutic influence of Sertoli cells on the effects of oxidative stress in germ cells
Hynková, Marie ; Tlapáková, Tereza (advisor) ; Frolíková, Michaela (referee)
Sertoli cells are somatic cells found in the testes and have a function in supporting spermatogenesis and germ cell nutrition, but also in maintaining an anti-inflammatory environment and forming the blood-testicular barrier in the testes. They are intensively researched for their immunomodulating properties which can be used in transplant medicine or as a therapeutic tool in regenerative medicine. Following previous research confirming that mouse Sertoli cells share some characteristics of mesenchymal stem cells and have multipotent differentiation potential in vitro, experiments were conducted to determine their therapeutic capabilities. Sertoli cells have demonstrated the ability to promote the maintenance of sperm motility during testicular inflammation and reduce the amount of immotile sperm in vivo. Based on preliminary results, they can also reduce the amount of ROS produced by testicular cells affected by oxidative stress in vitro. Keywords: Sertoli cells, germ cells, infertility, oxidative stress, ROS
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Liver cells regeneration in mammals
Ťažký, Timotej ; Tlapáková, Tereza (advisor) ; Onhajzer, Jakub (referee)
Liver cell regeneration is an important biological process that allows mammals to maintain liver function while recovering from liver damage. Liver cell proliferation serves as the primary mode of liver regeneration, which in hepatocytes is activated by the transition from the G0 to G1 phase of the cell cycle. Proliferation is also promoted by non-parenchymal liver cells among which include Ito cells, Kupffer cells, and endothelial cells of hepatic sinusoids. In a comprehensive analysis of key signaling pathways, it was clearly demonstrated that the Wnt/β catenin, Notch, Hippo, NF-κB, and Hedgehog signaling pathways play a key role in the regulation of liver cell proliferation and differentiation during regeneration. The regenerative potential of the liver is influenced by various factors such as age, extent of damage and health conditions. Additionally, the remarkable regenerative capacity of the liver has clinical implications in the context of liver transplantation, partial hepatectomy and the treatment of liver diseases such as cirrhosis, hepatitis and hepatocellular or cholangiocellular carcinoma. Modulation of key signaling pathways and identification of novel molecular targets can improve the clinical outcomes of patients with liver diseases or even accelerate the entire process of liver...
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Influence of microchimeric cells on tumor growth
Šimková, Lucie ; Tlapáková, Tereza (advisor) ; Peltanová, Barbora (referee)
Microchimerism is caused by the presence of few genetically different cells in the human body. Microchimerism can arise, for example, during pregnancy, during which the bilateral cell migration occurs. The maternal cells that the child acquires during pregnancy and subsequent breastfeeding help to shape its immune system, for example. Blood transfusion or transplantation is another possibility for microchimerism. Microchimeric cells can be stored in an individual's body for decades and can thus also affect their health. These cells have stem cell-like attributes that allow them to incorporate into the damaged tissue. As a result, they can have a positive effect on tissue repair, but they can also cause autoimmune diseases or influence the development or suppression of cancer.
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In vitro 3D organization of the mammalian testes
Zahradníková, Hana ; Tlapáková, Tereza (advisor) ; Janečková, Lucie (referee)
A testicular organoid that would sufficiently recapitulate the architecture of the testicular tissue and at the same time be able to provide the complete process of spermatogenesis in vitro has not yet been created. Achieving this goal would mean the development of a 3D model of the testis, which would mimic the in vivo situation in terms of cell arrangement and could thus contribute to a deeper understanding of the physiological functioning of the testicular microenvironment. Among other things, such a model has a great potential for clarifying the causes of male infertility and finding treatment options. This thesis dealt with the generation of organoids from mouse or human testicular cell suspensions, which can also be used, for example, to study de novo organogenesis. A total of four 3D culture systems were tested, of which the soft agar culture system (SACS) achieved the best results. Furthermore, as part of this thesis, the procedure for preparing testicular organoids for light sheet microscopy was successfully introduced and optimized, enabling the evaluation of their internal structure. From the testicular cell suspension of a 5-day-old mouse, it was possible to prepare testicular organoids, the structure of which in some respects resembled the organization of the testis in vivo. The...
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Role of oxidative stress in male infertility.
Dolečková, Barbora ; Tlapáková, Tereza (advisor) ; Šanovec, Ondřej (referee)
Oxidative stress is a phenomenon caused by an excess of reactive oxygen species (ROS), or by insufficient activity of antioxidants, that reduces these ROS levels and thereby protect the organism from oxidative damage. ROS have two types of origin: endogenous, which includes leukocytes and immature sperm, and exogenous, which includes factors such as air pollution caused by heavy metals, smoking tobacco products, obesity and others. Low levels of ROS have a positive effect on the physiological functions of the organism, including the process of spermatogenesis, where ROS participates in the course of hyperactivation and capacitation. However, increased levels of ROS trigger a number of cellular pathologies, whether the loss of fluidity of biological membranes due to lipid peroxidation, deformation of enzymatic proteins or DNA fragmentation, which negatively affects individuals' infertility. Due to the significant positive correlation of ROS scavenging by antioxidants with improving sperm parameters of an infertile individual, antioxidant therapy has recently begun to be used as a possible successful component of male idiopathic infertility treatment.
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Effect of estrogens on in vitro models of testicular tissue and spermatogenesis
Jursová, Pavlína ; Děd, Lukáš (advisor) ; Tlapáková, Tereza (referee)
Although estrogens are primarily known for their functions in female reproductive system, their effect on male reproductive functions has also been well established. Physiological estrogen concentration is essential for a proper spermatogenesis. Estrogens regulate many functions in testicular tissue, including proliferation and apoptosis of all testicular cell types, dynamic restructuring of cell-cell junctions in the testis, and post-translation modifications of histones. Hence, the aim of this thesis was to study effect of estrogens on in vitro models of testicular tissue and spermatogenesis and thus to address their functions in testicular tissue more deeply. This project includes testicular organoid cultivation for further usage as in vitro model of spermatogenesis. To addresss the effect of various avaliable estrogen forms, experiments on MCF-7 cell line were done. Finally experiments with in vitro model of testicullar tissue - TM4 Sertoli cell line were done. In order to fulfill the aims and verify the hypotheses, some advanced methods such as CLARITY volume confocal imaging and holographic microscopy were used. It was found that estrogens can affect Sertoli cell morphology and the expression of some genes involved in cell-cell junction dynamics. Furthermore the process of spermatogenesis was...
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Effect of oxidative stress on the differentiation of mesenchymal stem cells.
Bura, Radek ; Tlapáková, Tereza (advisor) ; Pacherník, Jiří (referee)
Mesenchymal stem cells are capable of forming different types of tissue such as muscle, bone, fat or cartilage tissue, thanks to the ability to divide and transform into another cell type. Mesenchymal stem cells obtained from various tissues are used for cell therapy and regenerative medicine. Knowledge of the influence of various factors on the differentiation of these multipotent cells is important. Currently, little is known about the effect of reactive oxygen species (ROS) on the differentiation potential of mesenchymal stem cells. The aim of this bachelor's thesis is to summarize the knowledge of the effect of oxidative stress on the differentiation of mesenchymal stem cells and the affected signaling pathways.
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Epithelial uric acid transport proteins and their allelic variants
Vrzáčková, Aneta ; Tlapáková, Tereza (advisor) ; Pavelcová, Kateřina (referee)
In humans, uric acid is the end product of purine metabolism and it is excreted from the body on the one hand by the epithelium lining the tubules of the nephrons, and on the other hand by the intestinal epithelium. This work aims to verify the activity of three candidate transporters from the SLC family (SLC2215, SLC22A18 and SLC47A1) that could transport uric acid in the intestinal epithelium. Preliminary results did not demonstrate that these transporters are involved in uric acid transport in the intestinal epithelium. Furthermore, the work deals with the influence of the W75C allelic variant of the SLC17A1 transporter and the mechanism by which this variant affects the transport of urate in cells. Key words: SLC22A15, SLC22A18, SLC47A1, SLC17A1, transport, epithel, uric acid
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The role of caspase-3 in apoptosis
Kolářová, Karolína ; Tlapáková, Tereza (advisor) ; Anděra, Ladislav (referee)
Caspases provide anti-inflammatory, apoptotic and developmental processes in organisms. They are enzymes with a wide range of activities in all cells, and various pathogeneses can occur if their proper function is disturbed. Since the 1990s, caspases have been a topic of interest for scientists, as their direct link to the triggering of apoptotic processes is a promising possibility for the therapy of diseases related to apoptosis, such as cancer, neurodegenerative diseases, but also cardiac ischemia and diabetes. The cascade of apoptotic processes is controlled by the aforementioned caspases, which are located in the caspase cascade. When the cascade is triggered in a cell, it is due to the presence of a "danger" signal, which can be very different. The most well-known triggers of the apoptotic cascade include activated Fas receptor and FasL ligand, cytochrome c present in the cytoplasm, an imbalance of IAPs in the cell, damaged DNA, and many others. Upon receipt of a signal, initiator caspase-2, caspase-8, and caspase-9 are activated, which in turn activate effector caspases-3, caspase-6, and caspase- 7, cleaving many substrates to promote apoptosis. Thus, caspase-3 is the effector enzyme responsible for the actual execution of apoptosis. However, caspase-3 properties are not only apoptotic, it...
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