National Repository of Grey Literature 34 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The study of Xenopus tropicalis testis-derived stem cells
Nguyen, Thi Minh Xuan ; Krylov, Vladimír (advisor) ; Bartůněk, Petr (referee) ; Hovořáková, Mária (referee)
The study of Xenopus tropicalis testis-derived stem cells Nguyen Thi Minh Xuan Abstract The substances secreted by Sertoli cells (SCs) are crucial to determine male sex characteristics in embryos and regulate spermatogenesis in adulthood. The failure in SC maturation can cause sterility in men. Before puberty, SCs keep the ability to proliferate and have been considered as immature cells. They differ remarkably from mature cells in connection with their morphology and biochemical activity and thus they probably play a part in maintaining spermatogonia stem cells in an undifferentiated stage. The transient presence of cytokeratin in immature SCs has been reported in many species, but not in Xenopus yet. We investigated which molecules are expressing only in immature Sertoli cells of X. tropicalis testes. The regulation of cytokeratin and β-catenin was revealed by fluorescent immunostaining. Cytokeratin and membrane β-catenin co- expressed in X.tropicalis juvenile testes and in cultured SC progenitors, called XtiSCs, but they were absent in adulthood. There was no signal of cytokeratin in migrating SCs (pre-SCs) located outside the seminiferous tubules. The suppression of cytokeratin along with the breakdown of β-catenin-based cell contacts have been observed in XtiSCs after the treatment with a small...
DISP3/PTCHD2 function in neural cells
Konířová, Jana ; Bartůněk, Petr (advisor) ; Anděrová, Miroslava (referee) ; Pacherník, Jiří (referee)
DISP3 protein, also known as PTCHD2, belongs to the PTCHD family of proteins, which contain a sterol-sensing domain in their structure. The expression of the Disp3 gene is high in neural tissues and is regulated by thyroid hormone. The DISP3 gene is associated with development and progression of certain types of tumors, as well as with development of some neural pathologies. Neural stem cells also display high expression of the Disp3 gene. Neural stem cells are defined by their capability to self-renewal and capacity to differentiate into the basic types of neural cells - neurons, astrocytes, and oligodendrocytes. Precise regulation of the balance between proliferation and differentiation of neural stem cells is crucial for development of the central nervous system and its subsequent proper functioning, and disruption of this balance may lead to development of various pathologies. In this work we mainly focused on describing the function of the DISP3 protein in neural cells and tissues. We have shown that during differentiation of neural stem cells, the expression of the Disp3 gene is significant decreased. Furthermore, we have found that in neural stem and progenitor cells, the increased expression of the Disp3 gene promotes their proliferation. Moreover, when Disp3 expression was disrupted, the...
Anaemia disease models
Vondráková, Zuzana ; Bartůněk, Petr (advisor) ; Stopka, Tomáš (referee)
Hematopoiesis is a process by which blood cells are generated. All vertebrates have two phases of hematopoiesis - primitive and definitive. The main purpose of primitive hematopoiesis is the production of red blood cells, which provide oxygenation to the developing embryo. Other blood cell lineages are established by definitive hematopoiesis. The main function of erythrocytes is oxygen transport to all tissues. When erythrocyte production is decreased or they are damaged due to the membrane, enzyme or hemoglobin impairment, the condition called anemia arises. Sickle cell disease and β-thalassemia are called hemoglobinopathies as they are caused by the damaged hemoglobin. Fanconi anemia is caused by mutations in one of 21 genes of Fanconi anemia pathway, which plays an essential role in DNA repair. Diamond Blackfan anemia is caused by mutations gene for ribosomal proteins. Human cells, Mus musculus, Gallus gallus, Xenopus laevis and Danio rerio seem to be good models for study of this diseases and they are also useful for achieving therapeutical goals.
Haematopoiesis in Sea lamprey
Kovář, Martin ; Bartůněk, Petr (advisor) ; Živný, Jan (referee)
To find out if the haematopoietic system is common feature of vertebrates, we decided to examine haematopoiesis in a sea lamprey (Petromyzon marinus). All blood cells arises from the haematopoietic stem cells in higher vertebrates. We assume that this is common for the higher vertebrates and a jawless vertebrates, but nobody was interested in the jawless haematopoiesis since 1970. Using a reverse genetic, we identify homologues of important hematopoietic of higher vertebrates in transcriptome of the sea lamprey with emphasis on important receptors or transcription factors, because they can be used as the specific markers of different blood cells and their progenitors. Then we use those sequences for cloning, expression measurements and other work. We picked up sea lamprey as model organism because its unique phylogenetic position, important foe evo-devo studies, but also because lack of elementary knowledge about sea lamprey haematopoiesis. Key words: Petromyzon marinus, haematopoiesis, HSC, evo-devo
High-throughput screening for the discovery of small molecules modulating cell fate
Ribeiro Pombinho, António José ; Bartůněk, Petr (advisor) ; Bařinka, Cyril (referee) ; Jiráček, Jiří (referee)
The discovery of chemical compounds able to modify the way cells proliferate, differentiate or die can lead not only to the formulation of new drugs for disease treatment or prevention but also to their use as biological probes in the study of the molecular pathways involved in these processes. In order to test thousands of these small molecules in cellular assays, instrument automation and assay miniaturization are necessary. In this thesis, applications of High-Throughput Screening campaigns are described. The Hypoxia and Wnt pathways involved in stem and cancer cell proliferation; the differentiation of hematopoietic, neural and mesenchymal stem cells; and the TRAIL pathway leading to selective cancer cells death were the main subjects chosen. With this approach, it was possible to test the effect of small molecules in eukaryotic cells and in unicellular organisms as exemplified by the search of compounds leading to the death of the protozoan parasite Leishmania. Several chemical compounds were identified as active in modulating cell fate. Of remark were: Monensin that inhibits the Wnt pathway and prevents the growth of tumors in a mouse model of colorectal cancer; Homoharringtonine that, only in combination with TRAIL, induces the death of cancer cells implanted in immunodeficient mice; and...
Mapping of regulatory elements within 5' region of the Disp3 locus
Oltová, Jana ; Bartůněk, Petr (advisor) ; Krásný, Libor (referee)
Dispatched 3 (Disp3), a thyroid hormone-regulated gene, is studied extensively in our laboratory. Phenotype of cells with overexpressed Disp3 and its expression pattern make it a perfect candidate for a molecular link between thyroid hormone action and cholesterol homeostasis in the brain. Moreover, we hypothesize that it might play a role in certain neurodegenerative disorders and brain tumours. This thesis is aimed at the process of regulation of this gene via thyroid hormone receptor (TR), specifically identification of responsive elements of the thyroid hormone receptor that are necessary for the regulation. Also, we searched for elements recognized by liver X receptor (LXR), as LXR binds to the same arrangement of repeats as TR and there are a number of genes regulated by both of them. We combined in silico analysis of the Disp3 locus with reporter luciferase assays. A cluster of six elements identified around the first exon with two of them being conserved among human and mice draw our attention. In order to analyze this sequence in more detail, reporter vectors of various truncations of 3 kb region around exon 1 were constructed and tested in reporter assays. Reporter assays did not reveal any substantial element activated by TR or LXR; on the other hand, region containing repressor element(s)...
Panels of steroid receptor reporter cell lines for compound profiling and development of selective ligands for estrogen receptor alpha and beta
Sedlák, David ; Bartůněk, Petr (advisor) ; Anzenbacher, Pavel (referee) ; Kasal, Alexander (referee)
of the Ph.D. thesis Steroid hormone receptors represent a major target in the drug discovery. As ligand inducible transcription factors, their activity can be modulated by small lipophilic molecules. The first part of this work describes a preparation of two panels of potent, selective and robust luciferase reporter cell lines on the unified cellular background in U2OS osteosarcoma cell line. This system consists of two panels of stable luciferase reporter cell lines for estrogen receptor α (ERα), estrogen receptor β (ERβ), androgen receptor (AR), glucocorticoid receptor (GR), mineralocorticoid receptor (MR) and progesterone receptor (PR). The first panel of reporter cell lines relies on the expression of the chimeric steroid receptors created by the replacement of the N-terminal part of the steroid receptor molecule by Gal4 DNA binding domain (Gal4 DBD) binding to 9 copies of Gal4 upstream activation sequences (Gal4 UAS) in the promoter of the pGL4 luciferase reporter vector. In the second panel of reporter cell lines the activation of either synthetic promoter containing multiple hormone response elements or viral promoter derived from MMTV LTR is mediated by full- length exogenously expressed steroid receptors. We have extensively validated both panels using 28 well established ligands, carefully...
Regulation of gene expression by thyroid hormone receptors
Oltová, Jana ; Fafílek, Bohumil (referee) ; Bartůněk, Petr (advisor)
Hormones coordinate various processes in living organisms and their action is mediated either by cell membrane receptors or nuclear receptors. Thyroid hormones (THs) have prominent effects on the growth, development, and many aspects of metabolism, embryogenesis and early life. Their receptors (TRs) belong to the nuclear receptor superfamily, whose members function as ligand-activated transcription factors, and depending on the context, they can act both as activators or as inhibitors of transcription. Thyroid hormone receptors are encoded by two genes, TRα and TRβ, and by alternative splicing multiple isoforms are generated. The major form of TR binds to T3-response element as a heterodimer with retinoid X receptor (RXR). TRs are able to bind T3-response elements (TREs) independently of ligand occupancy. TREs contain two or more subsequent half-site sequences of AGGTCA, which are usually arranged as direct repeats with four nucleotide spacing (DR4). TH-responsive target genes are involved in a wide range of cellular pathways. Example of such gene is Disp3, which might link TH and cholesterol metabolism in certain cell types.

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