|
|
Vývoj chemických regulátorů drah mikroRNA a RNAi
Bruštíková, Kateřina ; Svoboda, Petr (advisor) ; Bařinka, Cyril (referee) ; Pospíšek, Martin (referee)
MicroRNAs are noncoding RNAs inducing sequence-specific posttranscriptional inhibition of gene expression and represent the major class of small endogenous RNAs in mammalian cells. Over 2,500 of human microRNAs potentially regulating more than 60% of human protein-coding genes have been identified. MicroRNAs participate in the majority of cellular processes, and their expression changes in various diseases, including cancer. Currently, there is no efficient small chemical compound available for the modulation of microRNA pathway activity. At the same time, small chemical compounds represent excellent tools for research of processes involving RNA silencing pathways, for biotechnological applications, and would have a considerable therapeutic potential. The presented work represents a part of a broader project, whose ultimate goal is: (i) to find a set of small molecules allowing for stimulation or inhibition of RNA silencing and (ii) to identify crosstalks between RNA silencing and other cellular pathways. This thesis summarizes results from the first two phases of the project, the development of high-throughput screening assays and the high- throughput screening (HTS) of available libraries of small compounds. To monitor the microRNA pathway activity, we developed and optimized one biochemical...
|
|
|
Extracellular microRNAs in hematological malignancies and their use for diagnosis and treatment monitoring
Šulcová, Dominika ; Pospíšil, Vít (advisor) ; Čermák, Vladimír (referee)
MicroRNAs are short non-coding RNAs that negatively regulate gene expression at post-transcriptional level by interfering with mRNA translation and stability. Recently, microRNAs were surprisingly found to be present in various body fluids including blood plasma and serum, cerebrospinal fluid, saliva, milk or urine. These extracellular microRNAs are resistant to RNases and stable in high temperature or pH. Extreme stability of extracellular microRNAs is caused by their association with protective protein complexes (mostly with Argonaute proteins). MicroRNAs are frequently deregulated in cancer and specific tumor- related microRNAs can be also detected in body fluids, indicating that extracellular microRNAs can be used as tumor specific markers. This Bachelor thesis reviews basic principles of microRNA function and biogenesis with focus on extracellular microRNAs and their role in intercellular communication, and it highlights the role of extracellular microRNAs in hematological malignancies and their possible use in diagnosis and treatment.
|
|
|
Substrate cleavage by mammalian Dicer isoforms
Kubíková, Jana ; Svoboda, Petr (advisor) ; Pospíšek, Martin (referee)
Host organisms evolved antiviral responses, which can recognize the viral infection and deal with it. One of the frequent signs of viral infection in a cell is appearance of double-stranded RNA (dsRNA). One of the pathways responding to dsRNA is RNA interference (RNAi), which functions as the key antiviral defence system in invertebrates and plants. Mammals, however, utilize for antiviral defence a different dsRNA-sensing pathway called the interferon response. RNAi functions only in mammalian oocytes and early embryonal stages although its enzymatic machinery is present in all somatic cells, where it is employed in the microRNA pathway. A previous study indicated that the functionality of RNAi in mouse oocytes functions due to an oocyte-specific isoform of protein Dicer (DicerO ), which is truncated at the N-terminus. In my thesis, I aimed to assess whether DicerO processes RNAi substrates more efficiently in vitro than the full-length Dicer (DicerS ), which is found in somatic cells. Therefore, I developed Dicer purification protocol for obtaining both recombinant mouse Dicer isoforms of high purity. I examined their activity in a non-radioactive cleavage assay using RNA substrates with structural features characteristic of RNAi substrates. My results suggest that recombinant DicerO and DicerS do not...
|
|
|
Extracellular microRNAs and their role in pathologies especially in the field of gynecology and obstetrics.
Štěrbová, Monika ; Hromadníková, Ilona (advisor) ; Balušíková, Kamila (referee)
microRNAs (miRNAs) represent a relatively newly discovered group of RNA molecules and they serve to regulate gene expression. In spite of processes of differentiation, proliferation and apoptosis, miRNAs influence the whole biological systems, such as embryogenesis, oncogenesis, and immunity. There have been a number of experiments in recent years concerning diagnoses and predictions of complications during pregnancy, and tumour growth. Extracellular miRNA molecules participating in circulation of patients are used in the non-invasive diagnostics. RNA molecules usually get into the extracellular fluid during the apoptosis process. I chose four diseases, which extracellular miRNA have diagnostic potential - preeclampsia, intrauterine growth retardation, gestational diabetes mellitus and breast cancer - for my work. An aberrant expression of different levels of various extracellular miRNAs has been reported in these diseases but the clinical use of microRNAs in the diagnosis and prediction of those still requires further research and optimization. Keywords: breast cancer, extracellular nucleic acids, fetal growth retardation, gestational diabetes mellitus, microRNA, PCR, preeclampsia
|
|
|
The role of microRNA in hypoxic pulmonary hypertension
Tichý, Václav ; Hampl, Václav (advisor) ; Kolář, David (referee)
Pulmonary Arterial hypertension (PAH) is a devastating progressive disease that significantly decreases quality of life and has the average survival rate of only few years. One of the significant initiators of PAH is chronic hypoxia. After more than six decades of research that was initiated in 1946 by von Euler and Liljestrand, a new group of potential regulators of this pathology was discovered, that became heavily studied in the last five years. They are highly conserved molecules belonging to non-coding RNA. These 19-23 nucleotides long microRNA (miRNA) act as negative regulators of expression on various proteins. Many of them regulate traditional signalling pathways of hypoxic PAH (HIF-1, BMPR2) and miRNA is in turn regulated by other signalizations. Together, that creates an interconnected network of direct and indirect interactions and feedback loops, that we need to study in order to understand hypoxic PAH. This thesis summarizes findings about important miRNA molecules from the last few years and elucidates part of these regulatory mechanisms on several miRNA molecules (miR-17-92, miR-21, miR-210, miR-204 a miR143/145).
|
|
|
Study of the regulatory properties of oncogenic microRNAs under normal and pathologically altered conditions in order to detect new tumors.
Dusílková, Nina Borisovna ; Stopka, Tomáš (advisor) ; Machová Poláková, Kateřina (referee) ; Rohoň, Peter (referee)
Oncogenic microRNAs (miRNAs) are small RNA molecules that inhibit post-translational regulatory mechanisms at the epigenetic level. miRNAs are often deregulated in malignancies and due to their stability are detectable in non-cellular fractions of peripheral blood. In our laboratory, we have performed several studies that have investigated and utilized miRNAs as biomarkers for various hematological tumors (e.g., chronic lymphocytic leukemia, Hodgkin`s lymphoma) and solid tumors (e.g., breast cancer). The aim of these studies was to find the association of miRNAs with pathophysiological and clinical aspects of each disease. Here, we confirmed the importance of particular miRNA or its complex during disease monitoring. Combining clinical, molecular biological and statistical analyses, we were able to find miRNA sets that fulfilled not only a diagnostic role but also a prognostic role beyond expectations. The main focus of this thesis is on the investigation of microRNAs in the diagnosis of a hematological malignancy - primary cutaneous T-cell lymphoma (CTCL). Tumor specificity of some miRNAs has been demonstrated. Their aberrant expression in tissue samples of CTCL patients obtained from skin biopsies, correctly distinguished malignant disease from control samples of benign skin lesions. Here, we...
|
|
|
Postpartum expression of cardiovascular disease-associated microRNAs - comparison of expression levels between plasma, plasma exosomes and whole peripheral venous blood
Ševčíková, Adéla ; Hromadníková, Ilona (advisor) ; Korabečná, Marie (referee)
MicroRNA (miRNA) are short non-coding RNA molecules that regulate gene expression at the post-transcriptional level. Many miRNAs are involved in the pathogenesis of cardiovascular diseases, which is associated with altered gene expression. This work compares miRNA gene expression profiles among various biological sources - whole peripheral venous blood (whole PB), plasma and plasma exosomes. For all tested groups combined, the expression levels of miRNA were maximal in whole PB and lowered in plasma and plasma exosomes, and the expression levels of miRNA were higher in plasma than in plasma exosomes, except miR-126-3p, which had a higher level detected in plasma exosomes compared to plasma. This work also compares expression levels of cardiovascular miRNA between women with anamnesis of gestational diabetes mellitus (GDM) and physiological gravidity 3-11 years postpartum in whole PB, plasma and plasma exosomes. In whole PB, 12 of 29 tested miRNAs were up-regulated in women with prior exposure to GDM. MiR-181a-5p was up-regulated in plasma exosomes and miR-499a-5p in plasma in women with prior exposure to GDM. The changes in whole peripheral venous blood seem to reflect the complex systemic response to the changes that occurred during the onset of GDM. Women with aberrant epigenetic profiles may...
|
|
|
MicroRNAs encoded by polyomaviruses.
Zachovalová, Veronika ; Bruštíková, Kateřina (advisor) ; Malík, Radek (referee)
MicroRNAs are small regulating molecules of RNA that are encoded by orgamism's genome. Biogenesis of microRNA takes place partly in the nucleus and partly in the cytoplasm. Result of this biogenesis is a 22 nt long microRNA molecule. They are able to silence the genes thanks to sequence- specific degradation of a target mRNA or thanks to the repression of translation of target, complementary mRNA. In mammalian cells the mechanism of translational repression is more common. During this mechanism the microRNA molecule is not entirely complementary to 3'UTR of its target mRNA. Polyomaviruses are small, non-enveloped dsDNA viruses with a circular genome and icosahedral capsid composed of VP1 protein pentamers. These viruses belong in a group called onkoviruses, which can transform infected cells and contribute to development of serious illnesses such as Merkell cell carcinoma. Their genome encodes regulating proteins called T antigens, structural capsid proteins and also microRNAs. My main focus in this thesis will be SV40, MPyV, MCPyV, BKPyV and JCPyV encoded microRNA molecules. Key words: polyomaviruses, small interfering RNA, microRNA, siRNA, RNA interference, mouse polyomavirus, BK virus, JC virus, SV40
|
|
|
The Role of oncogenic microRNA - 155 and proto - oncogen MYB in chronic lymphocytic leukemia
Vargová, Karina
(EN) Chronic lymphocytic leukemia (B-CLL) represents a disease of mature-like B-cells. Due to failed apoptosis but also due to enhanced proliferative signals, the leukemic B-cells accumulate in the peripheral blood, bone marrow, lymph nodes and spleen. The clinical course of B-CLL is very heterogeneous; in some patients B-CLL progresses very rapidly into an aggressive form. Such patients need therapy sooner while in other patients with indolent B-CLL the onset of therapy takes years. Several standard prognostic and disease progression markers are used for disease staging and monitoring, however a reliable marker that will suggest when to start therapy is unknown. Expression of small, non-coding microRNAs is often deregulated and represent important prognostic markers in variety of cancers including leukemia. Hence in our study we concentrated to miR-155, an important molecule regulating differentiation of hematopoietic cells, inflammation process and antibody production. Its aberrant expression was described in Hodgkin`s as well as in non-Hodgkin`s lymphoma, including indolent lymphoproliferations like B-CLL. Our results confirmed elevated levels of both, primary miR-155 transcript and mature form of miR-155 in our B-CLL patient samples (N=239). The aberrant expression of miR-155 in B-CLL samples...
|
|
|
Delineating aggressiveness of acute myeloid leukemia in a mouse model carrying mutations of Spil (PU.1) and Trp53.
Bašová, Petra
PU.1 downregulation within haematopoietic stem and progenitor cells (HSPCs) is the primary mechanism for the development of acute myeloid leukaemia (AML) in mice with homozygous deletion of the upstream regulatory element (URE) of PU.1 gene. p53 is a well known tumor suppressor that is often mutated in human haematologic malignancies including AML and adds to their aggressiveness; however its genetic deletion does not cause AML in mouse. Deletion of p53 in the PU.1ure/ure mice (PU.1ure/ure p53-/- ) results in more aggressive AML with shortened overall survival. PU.1ure/ure p53-/- progenitors express significantly lower PU.1 levels. In addition to URE deletion we searched for other mechanisms that in absence of p53 contribute to decreased PU.1 levels in PU.1ure/ure p53-/- mice. We found involvement of Myb and miR-155 in downregulation of PU.1 in aggressive murine AML. Upon inhibition of either Myb or miR-155 in vitro the AML progenitors restore PU.1 levels and lose leukaemic cell growth similarly to PU.1 rescue. The MYB/miR-155/PU.1 axis is a target of p53 and is activated early after p53 loss as indicated by transient p53 knockdown. Furthermore, deregulation of both MYB and miR-155 coupled with PU.1 downregulation was observed in human AML, suggesting that MYB/miR-155/PU.1 mechanism may be involved...
|
guest ::
