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Analysis of chemotherapeutics in extracellular vesicles
Kožnarová, Simona ; Hložková, Michaela (referee) ; Vašinová Galiová, Michaela (advisor)
Extracellular vesicles are a newly discovered way of cell-to-cell communication. The issue is still significantly unexplored, especially in the case of cancer. The goal of this pilot study was to attempt to detect platinum contained in extracellular vesicles by ICP-MS. In this study, samples of ovarian cancer cell lines treated with platinum derivatives, a type of chemotherapeutic drug, were used. This method was proved as able to detect platinum, even as able to determine its concentration reliably. The quantity of platinum in vesicles was around 1–2 % of the total platinum added to the system. The results varied according to the used platinum derivative, the cell line and the number of cells releasing the vesicles. Most platinum was determined in vesicles of the SK-OV-3 line, which is naturally resistant to this treatment, for all platinum derivatives. From these results it can be concluded that the use of ICP-MS is also advisable for additional research on this issue.
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Large Extracellular Vesicles in Cell Culture and Blood: Role in Prion Transmission and Detection by Flow Cytometry
Soukup, Jakub
Prions (PrP) are the main cause of neurodegenerative diseases such as Scrapie in sheep, bovine spongiform encephalopathy, chronic wasting disease in deer, and Creutzfeldt-Jakob disease in humans. Although the cellular PrP (PrPC ) is involved in many cellular processes, its precise function still needs to be discovered. The disease is caused by the accumulation of a pathological form of PrP (PrPTSE ), which is caused by direct contact of PrPTSE and PrPC . PrP is anchored in the membrane by GPI and can be transmitted by cell-to-cell contact, tunnelling nanotubes, or extracellular vesicles (EVs). EV factions are divided by different biogenesis into exosomes, microvesicles, and apoptotic bodies. PrPTSE was found in exosomes and microvesicles, but these fractions were never compared to each other. The first aim of the doctoral thesis is a comparison of PrP content, prion-converting activity and infectivity in these fractions on CAD5 and N2a-PK1 cellular models of infection. We isolated a fraction of large EVs (20,000× g) and small EVs (110,000× g) by centrifugation from a conditioned medium. We characterised EVs by cryo-electron microscopy and western blot with Alix, TSG-101, CD63, CD9, and HSP70 markers. The contamination from other cellular compartments was checked by calnexin. EV fractions differed...
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Epigenetic inheritance influencing the behavior of future generations and its reversibility during ontogenesis
Freisingerová, Kateřina ; Landová, Eva (advisor) ; Švorcová, Jana (referee)
The aim of this work is to focus on possible mechanisms of transmission of changes that are conditioned by epigenetic modifications that could affect specific behaviour and phenotype in offspring. The inheritance can be channeled through both maternal and paternal lineages. It can be divided into two distinct groups of transmission, namely intragenerational and transgenerational. This work mainly focuses on the possible mechanisms of transgenerational inheritance. Epigenetic mechanisms leading to changes in the phenotype of an organism rely on influencing the regulation of DNA reading. This occurs at several levels such as DNA methylation, chemical modifications such as acetylation and other post-translational modifications, and most importantly non-coding RNA molecules. Today, countless studies are trying to explain these molecular processes mediated by environmental influences. Well known are maternal care, chemicals, or traumatic experiences. There are examples of traumatic environmental influences in which physiological changes in HPA axis regulation can be observed with consequent changes in the expression of genes for depressive and anxiety phenotypes. Most of the experiments focusing on epigenetic transmission are predominantly conducted in mouse or rat models. However, there are also...
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Large Extracellular Vesicles in Cell Culture and Blood: Role in Prion Transmission and Detection by Flow Cytometry
Soukup, Jakub ; Holada, Karel (advisor) ; Šebestová Janoušková, Olga (referee) ; Živný, Jan (referee)
Prions (PrP) are the main cause of neurodegenerative diseases such as Scrapie in sheep, bovine spongiform encephalopathy, chronic wasting disease in deer, and Creutzfeldt-Jakob disease in humans. Although the cellular PrP (PrPC ) is involved in many cellular processes, its precise function still needs to be discovered. The disease is caused by the accumulation of a pathological form of PrP (PrPTSE ), which is caused by direct contact of PrPTSE and PrPC . PrP is anchored in the membrane by GPI and can be transmitted by cell-to-cell contact, tunnelling nanotubes, or extracellular vesicles (EVs). EV factions are divided by different biogenesis into exosomes, microvesicles, and apoptotic bodies. PrPTSE was found in exosomes and microvesicles, but these fractions were never compared to each other. The first aim of the doctoral thesis is a comparison of PrP content, prion-converting activity and infectivity in these fractions on CAD5 and N2a-PK1 cellular models of infection. We isolated a fraction of large EVs (20,000× g) and small EVs (110,000× g) by centrifugation from a conditioned medium. We characterised EVs by cryo-electron microscopy and western blot with Alix, TSG-101, CD63, CD9, and HSP70 markers. The contamination from other cellular compartments was checked by calnexin. EV fractions differed...
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Extracellular vesicles and middle T antigen of mouse polyomavirus
Kropáček, Václav ; Šroller, Vojtěch (advisor) ; Brázdová, Andrea (referee)
This study is focused on middle tumor antigen (MT Ag) of mouse polyomavirus (MPyV), potential consequences of it's secretion via extracellular vesicles (EVs) and it's effect on cellular signaling. MT Ag is membrane bound protein able to induce cellular transformation thanks to it's ability to interfere with cellular signal transduction. Mainly due to aberrant activation of MAP kinase pathway. Firstly we followed up previous observations of our group concerning ability of MT Ag to be secreted from cells via extracellular vesicles. We were interested if MT Ag could contribute to malignant transformation in recipient cells. We performed 2 types of EVs isolation from cell lines stably expressing middle T antigen (3T6MT). We confirmed presence of MT Ag in isolated EVs. Then we characterized isolated EVs by detection of exosomal markers and cryo-electron microscopy. In next step we exposed recipient cell line (3T6) to isolated EVs and with use of flow cytometry tried to detect internalization of MT Ag. Simultaneously we tried asses levels of Erk phosphorylation in 3T6 cells exposed to EVs. Secondly we tried to confirm and analyse previous unpublished observations of elevated levels of NF-kB phosphorylation in cells stably expressing MT Ag. We used western blot and detection of NF-kB dependent secreted...
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Mechanisms of antigen presentation in the etiopathogenesis of celiac disease
Hudec, Michael ; Černá, Marie (advisor) ; Hrdý, Jiří (referee) ; Slavčev, Antonij (referee)
1 ABSTRACT Celiac disease (CeD) is a chronic autoimmune disease that develops as a response of the immune system to the presence of gluten in the small intestine. CeD is manifested not only by classic intestinal symptoms: abdominal pain, constipation or diarrhea, as well as complex less common symptoms: anemia, osteoporosis, psychiatric disorders or menstrual cycle disorders. HLA risk alleles predisposing to origin of celiac disease are HLA-DQ2 (DQA1*05:01 / DQB1*02:01) and HLA-DQ8 (DQA1*03:01 / DQB1*03:02). There are other celiac disease-associated polymorphisms outside of HLA locus (6p21.3) that are located in 5q32 and 19p13 regions with unclear connection to CeD development. HLA class II glycoproteins are expressed on antigen presenting cells (APC) that include dendritic cells, macrophages and B cells. Monocytes are one of several possible dendritic cell precursors that circulate in the bloodstream. Deviations in the frequency of intermediate monocytes are directly associated with autoimmune disorders such as Crohn's disease or rheumatoid arthritis. It is known that the monocytes of CeD patients show pro-inflammatory reaction in the presence of gluten. It means that, in the context of CeD, the response to gluten arises earlier than the activation of gluten-specific T cells. The conventional way of direct...
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Separation of exosomes from polydisperse suspension in microfluidic devices
Paříková, Anna
The work included fine-tuning the experimental methodology, writing an in-house code for exosome tracking based on a one-way\napproach, and performing a parametric study to investigate the separation potential of the microdevice as a function of channel geometry, flow rate, and viscosity. Preliminary results show that viscoelasticmicrofluidics can be used as an alternative to conventional e xosome separation techniques.
Plný tet:  PDF
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Molecular events associated with resistance to tyrosine kinase inhibitors in leukemia cells.
Hrdinová, Tereza
Chronic myeloid leukemia (CML) is a myeloproliferative stem cell disease characterized by the expression of BCR-ABL oncoprotein with constitutive tyrosine kinase activity. Although the development of tyrosine kinase inhibitors (TKI) such as imatinib dramatically improved the treatment of CML, a certain subset of patients develops resistance to TKI drugs. The most common cause of TKI resistance are point mutations in the BCR-ABL1 gene, followed by other mutation-independent mechanisms. Survival and proliferation of CML cells in the presence of TKI drugs are accompanied by adaptive changes in their metabolism. Drug resistance can be maintained by extrinsic signals, among which exosomes, small vesicles released by (drug-resistant) cells, have been shown to play an important role. The aim of this thesis was to characterize two CML cell lines sensitive and resistant to imatinib, as well as the exosomes derived from imatinib-resistant CML cells by proteomic approaches. Identification of metabolic vulnerabilities in drug-resistant cells enables their targeting by clinically available drugs, thus offering potential therapeutic targets for their selective elimination. Analysis of exosomes derived from imatinib-resistant cells can identify specific membrane surface proteins exploitable as clinically relevant...
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Phenotype of melanocytes under physiological and pathological conditions
Strnadová, Karolína ; Lacina, Lukáš (advisor) ; Mokrý, Jaroslav (referee) ; Balvan, Jan (referee)
In addition to the dominant keratinocytes and fibroblasts, melanocytes are also indispensable representatives of skin cell populations. Melanocytes are pigment cells whose primary function is to produce the pigment melanin, which is important for protecting keratinocytes from harmful ultraviolet radiation. Excessive exposure to this radiation is a risk factor for the development of skin tumours, including malignant melanoma of the skin, in which pathological transformation of melanocytes into melanoma cells occurs. The presented thesis focuses on 4 thematic areas associated mainly with malignant melanoma. In the first thematic area, the increasing incidence of malignant skin melanoma is associated with the ageing of the population. One of the reasons seems to be the more frequent occurrence of proinflammatory setting in the ageing organism. It prepares a suitable environment for tumour development. The second thematic area focuses on new approaches that could expand the range of diagnostic methods for the early detection of malignant melanoma. The first approach methodically uses the detection of proinflammatory molecules in the patient's serum. Higher serum levels of IL-6 and IL-8 correlate with an unfavourable patient prognosis. The second approach is based on the possibility of detecting a...
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miRNA analysis of small extracellular vesicles isolated from plasma after diet intervention
Kratochvílová, Michala ; Koc, Michal (advisor) ; Šrámek, Jan (referee)
The aim of this thesis was to establish a protocol for the isolation of small extracellular vesicles (sEVs) from human plasma. Plasma samples were collected from 44 healthy women who underwent a 60-hour dietary intervention in the form of fasting as part of a clinical trial. These women were divided into two groups based on their BMI - lean and obese. Plasma was collected from each participant before and after the dietary intervention and sEVs were isolated using the polyethylene glycol precipitation method. Each sample was then characterized by the size of sEVs and their concentration. The amount of sEVs in plasma before the dietary intervention was the same for both groups and did not change with dietary intervention. However, the 60-hour fasting resulted in a change in sEVs size in the lean group. Another goal of this thesis was to analyze miRNA expression in sEVs. There were differences found in the expression of certain miRNA between the two groups. More specifically, differences were observed in the expression of hsa-miR-17-5p, hsa-miR-20a-5p and hsa-let-7b-5p. The 60-hour fasting period resulted in an increased expression of hsa-miR-5100 in the lean group and hsa- miR-27a-3p and hsa-miR-27b-3p in the obese group. However, these changes induced by the dietary intervention were not evaluated...
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