|
|
Mebrane adaptor proteins in hematopoiesis and immune response
Pavliuchenko, Nataliia ; Brdička, Tomáš (advisor) ; Brábek, Jan (referee) ; Smrž, Daniel (referee)
Membrane adaptor proteins are proteins associated with cellular membranes that do not themselves serve as receptors. Instead, they propagate or modify the signals of these receptors by recruiting other signaling and regulatory proteins and arranging them into supramolecular complexes. In this thesis, I sought to describe selected membrane adaptor proteins and their roles in inflammation and regulation of hematopoiesis in mouse models using a reverse genetics approach. The main part of the work focused on the role of the membrane adaptor protein PSTPIP2 in suppressing inflammation. In mice, missense mutations in the Pstpip2 gene causing loss of PSTPIP2 protein lead to the development of autoinflammatory disease chronic multifocal osteomyelitis (CMO) characterized by sterile inflammatory lesions in the bones and adjacent soft tissue. These mice represent a model of the human autoinflammatory disease, chronic recurrent multifocal osteomyelitis. At the molecular level, neutrophils in the absence of PSTPIP2 exhibit pathological hyperactivity of pathways regulating IL-1β and reactive oxygen species (ROS) production, which are both implicated in the etiology of the disease. PSTPIP2 interacts with several signaling regulators, including PEST family protein tyrosine phosphatases (PEST-PTPs) and inositol...
|
|
|
Research of epigenetic aspects of hematopoietic and spermatogenesis stem cells.
Hybešová, Michaela ; Pimková, Kristýna (advisor) ; Děd, Lukáš (referee)
Stem cell differentiation is controlled by coordinated regulation of gene transcription. One of the regulatory factors is the loosening of chromatin and the accessibility of DNA to transcription factors. Chromatin remodeling is mediated by remodeling complexes. The ISWI chromatin remodeling ATPase Smarca5 (S5) is an important factor of remodeling complexes. It is a highly conserved chromatin-remodeling factor forming a catalytic subunit that can be found in several oligosubunit complexes. In these complexes, it actively regulates nucleosome structure and remodeling during DNA replication, repair and transcription. S5 has been identified as a key protein in embryonic development. Its deficiency leads to defects in hematopoiesis and male genital development. In the presented study, we focused on the role of S5 in hematopoiesis and spermatogenesis. Using a mouse model with transgenic expression of S5, co-immunoprecipitation and mass spectrometry, we identified S5 complexes in hematopoietic and testicular cells. We also studied the phenotypic consequences of S5 deficiency in mouse testes and found that it leads to impaired sperm development and male sterility. Using transcriptomic and proteomic analysis, we identified several molecular programs that could lead to reproductive disorders. Our work...
|
|
|
Hematopoietic stem and progenitor cell defects in transgenic model of Diamond-Blackfan anemia
Holečková, Markéta ; Kokavec, Juraj (advisor) ; Valášek, Leoš (referee)
Diamond-Blackfan anemia (DBA) is a rare congenital bone marrow failure syndrome characterized by deficient development of erythroid progenitors and accompanied by a variable set of developmental defects. About 25 % of patients have mutations of the small ribosomal subunit protein RPS19, and the precise mechanism of single aminoacidic mutations of RPS19 protein in the pathology of Diamond-Blackfan anemia remains largely unknown. To understand the interaction between of genotype and phenotypic variability we have created a mouse model with homozygous mutation in a highly conserved arginine 67 (Rps19R67Δ/R67Δ ). Mouse model with this mutation display many of the same phenotypical trades as patients with DBA. We decided to focus on hematopoiesis and erythropoiesis in this mouse model and tried to characterize those processes. We discovered that Rps19R67Δ/R67Δ mice similarly to DBA patients suffer from anemia and that the erythropoiesis process is disrupted at the stage of proerythroblasts. We also observed changes in hematopoiesis in stages as early as multipotent progenitors. The role of p53 protein as a modifier of DBA phenotype is well known. We created mouse model with p53 depletion to assess the role of p53 protein in relation with mutation in Rps19. Rps19R67Δ/R67Δ Trp53-/- mice show no signs of...
|
|
|
Selected aspects of redox metabolism in leukemogenesis
Myšáková, Michaela ; Pimková, Kristýna (advisor) ; Kuželová, Kateřina (referee)
Blood cancers are caused by the accumulation of mutations in haematopoietic stem cells. This creates a malignant clone that has a selection advantage due to improved survival and unrestricted proliferation, a process of leukaemia development called leukemogenesis. Leukemogenesis is a complex process and it is difficult to identify a single mutation that is responsible for the transformation of haematopoietic cells. In addition to transcriptional deregulation caused by oncogenic fusion proteins, mutations in specific genes that regulate critical signaling pathways play a critical role in leukemogenesis. Examples of such genes include mutations in the isocitrate dehydrogenase 1 and 2 genes (mutIDH1/2). These genes are thought to play an important role in the development of leukaemia, as indicated by their increasing frequency in the progression of myelodysplastic syndrome to acute myeloid leukaemia. The functions of mutIDH1/2 include epigenetic regulation, changes in metabolism and redox homeostasis. It has been shown that regulation of reactive oxygen species (ROS) production and elimination, so-called redox homeostasis, is important for the proper function of haematopoietic stem cells and its disruption is a frequent phenomenon accompanying malignant transformation of these cells. Some mutations,...
|
|
|
The role of HOXA9 gene in leukemogenesis
Rejlová, Kateřina ; Starková, Júlia (advisor) ; Fraiberk, Martin (referee)
The evolutionarily conserved family of homeobox genes plays an important role in the development of the anterior-posterior body axis of vertebrates. These genes significantly affect hematopoiesis, the development of blood cells. Extensive studies on homeobox genes in normal hematopoiesis confirmed their role also in leukemogenesis. Since the neoplastic transformation of blood cells, i.e. leukemia, is the most frequent malignancy in children, it has become a major subject of research for many scientists. Precisely in what stage of the malignant transformation the homeobox genes take part has not been shown yet. Neither is it known whether HOX genes are crucial in pathogenesis or whether their deregulation is only a side effect of leukemogenesis. The most studied homeobox gene in leukemogenesis is the HOXA9 gene, which showed correlation with the prognosis of patients with certain leukemias. Many studies describe the effect of HOXA9 in leukemic cell transformation, suggesting this gene could be a promising future target in leukemia therapy. This work is focused on the HOXA9 gene and its association with leukemic transformation of blood cells.
|
|
|
B- and T- lymphocyte subpopulations in lymphocyte-associated immunodeficiencies
Šinkorová, Vendula ; Kalina, Tomáš (advisor) ; Javorková, Eliška (referee)
The antigen-specific immunity consists of cells called T and B lymphocytes. These cells together with cells of non-specific (innate) immunity begin their development in fetal liver and later in bone marrow from the common progenitor, the hematopoietic stem cell. Both B and T lymphocyte lineages then undergo differentiation which is regulated by many cytokines and transcriptional factors and leads to very heterogeneous cohort of subsets. Because the immune system is not only protecting the organism from infections and malignant growth but also from itself, lymphocyte differentiation must pass many checkpoints where B and T clones are strictly selected. Cells of both lineages closely communicate with each other and also with cells of innate immunity. If, due to mutation of protein encoding genes, disturbance of differentiation or malfunction of effector activities providing some of these functions occurs, an immune system malfunction called immunodeficiency arises. Multiparametric immunophenotyping followed by flow cytometry examination has been proven one of the most suitable techniques for studying lymphocyte subsets and lymphocyte- associated immunodeficiencies. Here we describe examples of primary lymphocyte- associated immunodeficiencies, how they affect individual lymphocyte subsets, what it...
|
|
|
Role of Smarca5 (Snf2h) chromation remodeling ATPase in hematopoitic development and erythropoiesis
Kokavec, Juraj ; Stopka, Tomáš (advisor) ; Divoký, Vladimír (referee) ; Kořínek, Vladimír (referee)
The Imitation Switch (ISWI) nuclear ATPase Smarca5 (Snf2h) is one of the most conserved chromatin remodeling factors. It exists in a variety of oligosubunit complexes that move DNA with respect to the histone octamer to generate regularly spaced nucleosomal arrays. Smarca5 interacts with different accessory proteins and represents a molecular motor for DNA replication, repair and transcription. We deleted Smarca5 at the onset of definitive hematopoiesis (Vav1-iCre) and observed that animals die during late fetal development due to anemia. Hematopoietic stem and progenitor cells (HSPCs) accumulated but their maturation towards erythroid and myeloid lineages was inhibited. Proerythroblasts were dysplastic while basophilic erythroblasts were blocked in G2/M and depleted. Smarca5 deficiency led to increased p53 levels, its activation at two residues, one associated with DNA damage (S-18) second with CBP/p300 (K376Ac), and finally activation of the p53 targets. We also deleted Smarca5 in committed erythroid cells (Epor-iCre) and observed that animals were anemic postnatally. Furthermore, 4- OHT-mediated deletion of Smarca5 in the ex vivo cultures confirmed its requirement for erythroid cell proliferation. Thus, Smarca5 plays indispensable roles during early hematopoiesis and erythropoiesis.
|
|
|
Lineage plasticity in normal and malignant lymphocyte precursors
Rezková Řezníčková, Leona ; Froňková, Eva (advisor) ; Otáhal, Pavel (referee)
Klasické schéma vývoje hematopoetických buněk předpokládá časné oddělení lymfoidního a myeloidního prekurzoru. V poslední době jsou navrhovány složitější modely, které předpokládají větší flexibilitu hematopoezy a navrhují existenci progenitorů s lymfoidním i myeloidním potenciálem. Akutní hybridní leukémie jsou malignity, které podle různých kritérií nelze jednoznačně zařadit k lymfoidní nebo k myeloidní linii a jejichž chování spíše dává za pravdu novým modelům hematopoezy. Předkládaná práce se zabývala především výzkumem dětských leukémií s přesmykem z lymfoidní do myeloidní linie během indukční léčby. Jedná se o rozsáhlý projekt, v jehož rámci si diplomová práce si kladla za úkol určit liniové zařazení leukemických blastů pomocí detekce přestaveb genů pro imunoglobuliny a T-buněčné receptory (TCR). Potvrdili jsme, že myeloidní buňky derivované v průběhu léčby pochází u všech pacientů z původního lymfoidního klonu. Dále jsme u těchto případů zkoumali expresi vytipovaných genů ve srovnání s běžnými druhy leukémií. Třetí částí práce byl výzkum prognostického významu přítomnosti přestaveb TCR (a tedy příslušnosti k lymfoidní linii) u leukémií z T-lymfoidní řady.
|
|
|
The role of Kit ligands in hematopoiesis of Danio rerio
Oltová, Jana
Hematopoiesis is a precisely regulated process, dependent on the activity of hematopoietic cytokines and their receptors. Due to an extra round of whole genome duplication in teleost fish, two paralogs of many important genes, including some hematopoietic cytokines and their receptors, are present in the zebrafish (Danio rerio) genome. In this project, we have been investigating the role of zebrafish Kit ligands in hematopoiesis. Kit ligand is a pleiotropic cytokine, which is essential for vertebrate erythropoiesis; however, in zebrafish, no such role has been reported so far. To determine the function of zebrafish paralogs of Kit ligand (Kitlga and Kitlgb) in hematopoiesis, we performed in vivo and ex vivo gain- and loss-of-function experiments. Strikingly, we were the first to report the synergistic cooperation of zebrafish Kitlga with erythropoietin and dexamethasone, enabling the growth of kidney marrow-derived suspension cells and providing optimal conditions for the expansion of adult erythroid progenitors. We assume that by using different cytokine combinations, optimal conditions for the growth of other hematopoietic cell types can be established, and therefore, this new approach now available for the...
|
|
|
Lineage plasticity in normal and malignant lymphocyte precursors
Rezková Řezníčková, Leona
The classical scheme of hematopoiesis presumes early separation of lymphoid and myeloid precursors. Recently, more complex models are put forward, suggesting greater flexibility of hematopoiesis with progenitors sharing lymphoid and myeloid potential. Acute hybrid leukemia is a malignancy, in which it is not possible to assess unambiguously myeloid or lymphoid lineage of origin. The behaviour of those malignancies favors new models of hematopoiesis. Our work concentrated mainly on the research of childhood leukemias with lineage switch from lymphoid to myeloid lineage during induction treatment. Our task within this extensive project was to determine lineage assignment of leukemic blasts using detection of immunoglobulin and T-cell receptor gene rearrangements. We confirmed that myeloid cells derived during the treatment in all patients descend from the original lymphoid clone. We also investigated the expression of selected genes in those cases compared to common leukemia types. Lastly, we explored prognostic impact of TCR rearrangements (and thus lymphoid lineage commitment) in T-lineage leukemia.
|
guest ::
