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Neurogenesis and gliogenesis after ischemic brain injury in EGFP/GFAP mice
Dlouhá, Veronika ; Anděrová, Miroslava (advisor) ; Vargová, Lýdia (referee)
Focal ischemia induces enhancement of neurogenesis/gliogenesis in the subventricular zone (SVZ) of the lateral ventricle and it also leads to glial scar formation in the vicinity of the ischemic lesion. The gliotic scar is mainly formed by reactive astrocytes that express glial fibrilarly acidic protein (GFAP), nevertheless this protein is also expressed in adult multipotent neural stem cells (NSCs). Therefore, we have used the strain of transgenic mice (GFAP/EGFP mice), in which the enhanced green fluorescent protein (EGFP) is expressed under human GFAP promoter in astrocytes as well as in NSCs, thus allowing us an immediate vizualization of these cells, and to estimate the effect of ischemic injury on their fate during proliferation and differentiation in vitro. Focal ischemia was induced by the occlusion of the middle cerebral artery (MCAO) and 3 days post injury, an immunohistochemical analysis was carried out. Furthermore, the cell isolation from SVZ and the region of gliotic scar was performed, followed by their cultivation under proliferative conditions (as neurospheres) and their differentiation for 7-10 days. The differentiation potential of these cells was studied using immunocytochemical analyses and patch clamp technique was employed to estimate their membrane properties. Based on increased...
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The Role of Aquaporin 4 channels and Transient Receptor Potential Vanilloid 4 channels in astrocytic swelling
Heřmanová, Zuzana ; Anděrová, Miroslava (advisor) ; Machová Urdzíková, Lucia (referee)
Astrocytes posses a wide range of functions within the brain. In response to ischemic conditions they swell due to increased uptake of osmolytes and they are mainly responsible for cytotoxic edema formation. However, they are also able to regulate their volume by releasing osmolytes together with water via the process of regulatory volume decrease (RVD). The Aquaporin 4 (AQP4) channel and Transient receptor potential vanilloid 4 (TRPV4) channel are suspected to be strongly involved in these processes of astrocytic volume regulation. The goal of the present diploma thesis was to clarify the role of both channels in astrocytic swelling in situ. For our experiments we used a subpopulation of green fluorescent protein-labelled astrocytes from AQP4-deficient (AQP4-/- ), TRPV4-deficient (TRPV4-/- ) and control (Ctrl) mice. Cell volume alterations were induced in acute brain slices by hypoosmotic stress or by oxygen-glucose deprivation (OGD). Data were quantified using fluorescence intensity-based approach in the whole cells and in astrocytic endfeet. Our results indicate, that there is no difference in astrocytic swelling or cell volume recovery between astrocytes from AQP4-/- , TRPV4-/- and control mice when exposed to hypoosmotic stress. On the contrary, volume changes induced by OGD varied...
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Calcium signalling in astrocytes under physiological and pathological conditions
Svatoňová, Petra ; Anděrová, Miroslava (advisor) ; Kolář, David (referee)
Calcium signalling in astrocytes represents an important component, which enables proper neuronal functioning under physiological conditions. Alterations in Ca2+ signalling, accompanied by an increase in intracellular calcium levels is a hallmark for numerous pathological states of central nervous system, such as traumatic and ischemic brain/spinal cord injuries, epilepsy as well as neurodegenerative diseases, such as Alzheimer's disease and psychiatric disorders, such as schizophrenia. The research analyzing the molecular components of astrocytic Ca2+ signalling can help us understand the control mechanisms used in calcium signalling and thus be greatly beneficial for further therapeutic research. Powered by TCPDF (www.tcpdf.org)
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Proteomic analysis of cellular proliferation and differenziation: Model of neural stem cells and cancer cells
Skalníková, Helena ; Kovářová, Hana (advisor) ; Anděrová, Miroslava (referee) ; Bezouška, Karel (referee)
CoNcLUsIoNs In protein profiling of neural stem cells using 2-dimensional gel electrophoresis and mass spectrometry, constitutively expressed proteins in 66 protein spots were identified. Most of the individual protein species were related to RNA and protein metabolism, processing and turnover, including some chaperones and stress response proteins. Proteins involved in cellular organization (e.g. cýoskeletal proteins and annexins), metabolic proteins (mostly enrymes),cellular energetics,cell defenseand signallingfollowed in lower numbers. Proteins in 16 spots significantly regulated during neural differentiation were identified. Induction of levels of o-B crystallin, hnRNP Al and hnRNP AZIBI during differentiation and protein localization within neural cells were studied by westernblottingand immunocýochemistry. Using antibody microarrays, in neural stem cells an increase in GRK2 level and phosphorylationsof signalling molecules(CDKI|Z, PKC mu, PKCy, Erk5 and o-B crystallin) involved mostly in cellular proliferation were detected.On the contrary, in differentiatedneural cells levels of protein-phosphatase4, heme-oxygenase2, MEK3, RafB, pro-caspase 1 and phosphorylation of 40 kDa proline-rich Akt substratewere induced. In cancer cells after protein separationby ProteomelabrM PF 2D system, 8 proteins...
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Polydendrocytes and their role in CNS
Suchá, Petra ; Anděrová, Miroslava (advisor) ; Tvrdoňová, Vendula (referee)
Polydendrocytes (NG2+ cells) are recently discovered glial cells in central nervous system (CNS) distinct from neurons, oligodendrocytes, astrocytes and microglia. Polydendrocytes could be identified mainly by the expression of the proteoglycan NG2 and platelet derived growth factor receptor alpha. They could be found in grey and white matter and represent the largest proliferating cell population in adult CNS. It is accepted that a subpopulation of polydendrocytes gives rise to oligodendrocytes not only in development, but also in adult CNS and after demyelination. A subpopulation gives rise also to protoplasmic astrocytes in embryonic development. In in vitro studies was observed that neurons and astrocytes may arise from polydendrocytes. Electrophysiological studies revealed that polydendrocytes form synapses with neurons and that their rate of proliferation could be controlled this way. Polydendrocytes are very important in study of remyelination after ischemia and demyelinating diseases, as they might serve as source of new oligodendrocytes or possibly of another glial cells. This thesis summaries general knowledge about polydendrocytes. Initially, I focus on their immunohistochemical markers and morphology. Next, I summarise findings about their development and fate in both embryonic and adult CNS. A...
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Membrane Properties of Glial Cells after Ischemia in vivo
Pivoňková, Helena ; Anděrová, Miroslava (advisor) ; Vyklický, Ladislav (referee) ; Vlachová, Viktorie (referee)
In my PhD thesis, I aimed to characterize the membrane properties of astrocytes and NG2 glia during the acute and chronic phases of the ischemic injury in the central nervous system with a focus on the expression and activity of K+ ion channels. Two ischemia models in rats were used for the experiments - global cerebral ischemia 5 causing selective neuronal loss and astrogliosis in the CA1 region of the hippocampus, and incubation of spinal cord segments in a solution with high K+ concentration. We found that hippocampal astrocytes depolarize starting 3 days after ischemia, and demonstrate an increase in the inward rectification of their whole cell currents 1 month after ischemia. The Kir4.1 channel expression in the hippocampal tissue was downregulated starting 3 days after ischemia, while the expression of Kir2.1, Kir5.1 and TREK1 channels was strongly upregulated in reactive astrocytes 1 month after ischemia. NG2 glia displayed a significant increase in the outwardly rectifying delayed and A-type K+ (KDR and KA) currents 2 hours and 3 days after ischemia, and a decrease in the inwardly rectifying K+ currents 3 days after ischemia, a typical current pattern of proliferating cells. Complex astrocytes in the spinal cord pre-incubated in a solution with high [K+] showed the largest changes in their membrane...
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The effect of the canonical Wnt singalling pathway on the differentiation of polydendrocytes after ischemic brain injury
Knotek, Tomáš ; Anděrová, Miroslava (advisor) ; Romanyuk, Natalyia (referee)
Polydendrocytes, or NG2 glia, are fourth type of glial cells in mammal central nervous system. In the adult brain, NG2 glia represent important cell type with respect to their role in gliogenesis and nervous tissue regeneration following injury. Ligands from the Wingless/Int (Wnt) family play key role in proliferation and differentiation of NG2 glia and they can also influence regeneration of nervous tissue after ischemia. The aim of this thesis was to elucidate the role of NG2 glia in neurogenesis and gliogenesis following ischemic brain injury and investigate the impact of Wnt signalling on the reaction of NG2 glia to this type of injury. To fulfil these aims, transgenic mouse strains with tamoxifen-inducible recombination, that enabled simultaneous expression of red fluorescent dye and either activation or inhibition of the Wnt signalling pathway in NG2 glia, were employed. To induce ischemic injury, middle cerebral artery occlusion model was used. Changes in differentiation and electrophysiological properties of NG2 glia were analysed using patch-clamp technique. Activation of the Wnt signalling pathway under physiological conditions and 7 days after ischemic injury led to increased differentiation of NG2 glia toward astrocytes, while 3 days after ischemic injury activation of this signalling...
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The role of astrocytes in the formation of brain edema
Heřmanová, Zuzana ; Anděrová, Miroslava (advisor) ; Pačesová, Dominika (referee)
Brain edema is a cause of mortality accompanying number of pathologies such as ischemia, traumatic brain injury, tumors or liver and kidney failure. It is described as a process of osmotic and water flux alterations, which lead to cell volume changes and to an increase in intracranial pressure. Brain edema is usually classified into two types: vasogenic and cytotoxic. Development of vasogenic edema is connected to the blood brain barrier disruption. Water accumulates in the extracellular space and exerts pressure on the cellular compartments of the tissue. The cytotoxic type of edema is characterized by water accumulation within the cells. The process of cellular volume enlargement is termed cellular swelling. Cytotoxic swelling is usually connected to glial cells, namely astrocytes, as these cells represent a part of the blood brain barrier and thus they influence homeostasis inside the brain. Water flows across cytoplasmic membrane through a system of specialized channels - aquaporins. For the brain edema formation, aquaporin 4 is the most important. It is localized on astrocytic membranes and using aquaporin-null mice, it has been shown, that it participates in water clearance in physiological and pathological conditions. Since the water fluxes are passive, the driving force for edema formation...
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Nervous tissue regeneration following ischemic injury in adulthood - the role of glial cells
Kamenická, Monika ; Anděrová, Miroslava (advisor) ; Kletečková, Lenka (referee)
Ischemic stroke (ischemia) is one of the most common causes of death in the world. The consequences of this disease are enormous and markedly affect the lives of patients who often are unable to live a full quality of life as before. Therefore, the current research is focused on elucidating new mechanisms that could mitigate the effects of ischemia and better regeneration of nerve tissue. This theses aims to summarize the current knowledge about neurogenesis/gliogenesis in the nerve tissue under physiological conditions, after ischemic injury and subsequent regeneration. The first chapter is focused on neurogenesis in the nervous tissue of adults. The two main neurogenic regions are described, such as subventricular zone and the gyrus dentatus in hippocampus. The following is a brief description of cells that are located in neurogenic regions and their function under physiological conditions. The second chapter focuses on gliogenesis in adult nervous tissue and describes the glial cells responsible for numerous functions in CNS. Furthermore, the functions of individual types of glial cells are listed. The third chapter gives the overview about pathophysiology of ischemia. The author tries to explain what is happening in the brain tissue during and following ischemia, what types of ischemia are...
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