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Hematopoiesis in the models of zebrafish and medaka as a recipient for human HSC xenograft
Pravcová, Naďa ; Drbal, Karel (advisor) ; Svoboda, Ondřej (referee)
Danio rerio (zebrafish) and Oryzias latipes (medaka) have recently become popular model organisms to study hematopoiesis. These model organisms present several advantages in comparison to other commonly used models, the most common being Mus musculus (mouse). The advantages are shorter generation time, large offspring production, frequent spawning, external fertilization and development, the optical transparency of embryos amenable to genetic manipulation on the background of vast numbers of transgenic lines (mainly in zebrafish) and inbred strains (in medaka). Moreover, most of the mechanisms behind zebrafish and medaka hematopoiesis are conserved in higher vertebrates. Most importantly, the optical transparency in early development and in adult mutant transparent strains allows for observation of hematopoietic stem cell (HSC) development in vivo. Therefore, it is possible to generate humanized fish using xenotransplanted human HSCs for studies of the engraftment, differentiation, and trafficking of human HSC in vivo. Currently, the most popular organism for human HSC xenotransplantation is mice. This model system is not suitable for in vivo imaging of HSC engraftment. Moreover, a prior immunodepletion step is necessary. The process of immunodepletion includes genetic manipulation or irradiation...
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Characterization of hematopoietic cells in patients with mature B-cell malignancies
Maswabi, Bokang Calvin ; Živný, Jan (advisor) ; Otáhal, Pavel (referee) ; Alberich Jorda, Meritxell (referee)
(English) Using flow cytometry we analyzed absolute and relative proportions of hematopoietic stem and progenitors cells (HSPC) populations including hematopoietic stem cells (HSC), multipotent progenitors (MPP), multilymphoid progenitors (MLP) and pro B cells from bone marrow of patients with mature B cell malignancies and in healthy controls. We found lower absolute and relative numbers of MLP and higher relative numbers of HSC were observed in patients when compared to age-matched controls irrespective of bone marrow (BM) involvement. On the other hand significantly decreased absolute numbers of MPP were observed only in patients who had their BM infiltrated by disease. We also confirmed published data showing increasing absolute and relative percentages of MLP with increasing age, decreasing relative percentages of HSC with increasing age, and decreasing absolute and relative pro B cell frequencies with increasing age in healthy subjects. While decreased absolute and relative pro B cell numbers were also found in patient samples as age increased, no significant correlations were detected in patients HSC, MPP or MLP populations. Age-related sub-analysis of PTs samples demonstrated that most of the disease associated changes in HSPC frequencies were observable more prominently in the elderly (>45...
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The mechanisms and regulation of lineage commitment in hematopoietic stem cell
Tichý, Marko ; Stopka, Tomáš (advisor) ; Svoboda, Ondřej (referee)
Hematopoietic stem cells (HSCs) are crucial for maintaining balanced homeostasis in the human body. HSCs are pluripotent cells, which are able to give rise to many very different cells. HSCs can be found in fetal liver initially during organismal development where they expand and move to their more definitive location, the bone marrow, shortly before birth in humans and mice. HSCs possess to not only recapitulate themselves (self-renew) or proliferate and expand, but are also the first branching point from which subsequent multipotent progenitors and eventually all blood cell lineages are formed thus establishing specific and restricted terminal differentiation pathways. The irreversible decision to initiate and follow a specific differentiation pathway is designated as lineage commitment. The drivers of lineage commitment, which are a base of this thesis, are intrinsic as well as extrinsic factors acting within the stem cell niche, such as transcription factors, chromatin remodeling factors, and cytokines, which are essential for proliferation, survival, self-renewal and lineage commitment decisions. These regulatory factors, working either independently or in mutual coordination, maintain balanced homeostasis of HSC renewal and their differentiation. The goal of this thesis will be to ascribe the...
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