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The role of histone deacetylase 6 in murine polyomavirus replication cycle
Vlachová, Štěpánka ; Horníková, Lenka (advisor) ; Saláková, Martina (referee)
The replication cycle of polyomaviruses is, consistently with other viruses, fully dependent on host cells. Not only the cellular replicational and translational mechanisms are important for viruses, but also the virus infection is affected by other cellular proteins. This work is focused on the role of major cytoplasmic deacetylase, histone deacetylase 6 (HDAC6) in replication cycle of murine polyomavirus (MPyV). We showed that the presence of fully functional HDAC6 is essential for successful and productive infection. We found that HDAC6 affects not only early phase, but also late phase of infection. Cells with inhibited, or absent HDAC6 are infected with decreased effectivity and moreover lower amount of infectious viral particles is produced. On the other side, using cells with partially functional HDAC6, either in its deacetylase activity or in ubiquitin-binding activity, leads to increased ability of MPyV to infect those cells. Analysis of levels of early LT antigen and late structural protein VP1 in the infected cells showed, that viral proteins are affected by HDAC6. Our data suggest, that in the replication cycle of MPyV mainly the ubiquitin-binding domain of HDAC6 is required and the role of this domain in protein metabolism and degradation. In the second part of diploma project, we...
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Targeting of viral nanoparticles to cancer specific receptors
Žáčková Suchanová, Jiřina
The aim of this thesis is to reveal the potential of mouse polyomavirus (MPyV) based virus-like particles (VLPs) as possible nanocarriers for directed delivery of therapeutic or diagnostic compounds to specific cells or tissues. We have chosen mouse polyomavirus VLPs because they do not contain viral DNA and are considered safe for utilization in bio-applications. In our research, we used a chemical approach for retargeting of MPyV based VLPs from their natural receptor to cancer cells. The chemical modification of the capsid surface exposed lysines by an aldehyde-containing reagent enabled conjugation of VLPs to selected molecules: transferrin and inhibitor of glutamate carboxypeptidase II (GCPII). Transferrin, as a transporter of iron to metabolically active cells, targeted VLPs to numerous types of cancer cells overexpressing the transferrin receptor. On the other hand, GCPII serves as a transmembrane marker specific for prostate cancer cells and conjugation of its inhibitor to VLPs resulted in successful recognition of these cells. Electron microscopy was used for visualization of modified VLPs and flow cytometry together with confocal microscopy for investigation of cell specific interactions and VLP uptake. Furthermore, we explored the influence of serum proteins on VLPs. The abundance of...
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Experimental system for production of IL-15 on viral carriers
Musil, Dominik ; Španielová, Hana (advisor) ; Šmahel, Michal (referee)
Interleukin 15 has great application potential such as in the biological treatment of cancer. It is involved in a variety of immunological processes, the most important of these involve influencing and induction of NK cells and T-lymphocytes proliferation. However, its therapeutic usages are limited by a low stability and short half-life. For this reason, there are various approaches of stabilization and expansion of its biological activity being explored. In this work, we analysed and developed a new approach, which uses viral nanostructures derived from major capsid VP1 protein of mouse polyomavirus as a carrier of IL-15. Moreover, VP1 proteins can be relatively easily modified and they are also capable to penetrate into the tumour cells. There were prepared two variants of IL-15 together with control nanostructures in the baculovirus expression system, one was composed of IL-15 and the other of the IL-15 fusion protein and truncated variant of VP1. Protein constructs were characterized by electron microscopy and biochemical methods. The total protein yield of VP1ΔC-IL15-HIS fusion variant was higher (up to 53 mg/L of complete medium) than IL-15 alone (8,5 mg/L). However, testing of the biological activity of the prepared proteins in vitro did not show any induction of proliferation on Jurkat...
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Development of a technique for gene transfer into T-lymphocytes using polyomavirus structures and the LAH4 peptide
Schreiberová, Lucie ; Španielová, Hana (advisor) ; Vopálenský, Václav (referee)
Efficient delivery of genetic material to T-lymphocytes is key in gene therapy using T-lymphocytes with chimeric antigen receptors. Current procedures require the use of potentially dangerous viral vectors or large amount of input material. The diploma thesis therefore focuses on exploring new approaches for gene transfer into T-lymphocytes: use of safe virus-like particles (VLPs) derived from mouse polyomavirus in combination with the amphipathic cationic peptide LAH4. LAH4 has the potential to increase the efficiency of DNA and viral vector transport into cells. The system which combines VLPs and the LAH4 peptide was optimized for the delivery of reporter gene (encoding GFP and luciferase) to the model T-cell line Jurkat. It has been found that Jurkat cells cannot be efficiently transduced by DNA packed into VLPs. When cells were transfected only with DNA and LAH4, consistent results were not obtained, and the transfection efficiency ranged from 0.5 to 19%. The diploma thesis also analysed the effect of phosphorylation of viral structures on gene transfer. The impact of treatment of virus particles by alkaline phosphatase on the infectivity of the virus was studied and it was necessary to analyse the effect of the reaction components. Sublytic concentration of Triton-X100 in the reaction buffer...
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The role of proteins acetylation in life cycle of Polyomaviruses
Dostalík, Pavel ; Horníková, Lenka (advisor) ; Saláková, Martina (referee)
Capsid of mouse polyomavirus (MPyV) is composed from three structural proteins: major structural protein VP1 and minor structural proteins VP2 and VP3. Posttranslational modifications may affect functions of proteins. This work deals with acetylation of MPyV structural proteins and its impact on the viral replication cycle. First part of the thesis is focused on acetylation of VP1. We showed that the VP1 protein is acetylated in viral particles and that interaction of VP1 with minor proteins supports VP1 acetylation. Further, we showed that cytoplasmatic deacetylase, histone deacetylase 6 (HDAC6), is important for virus infectivity. Overexpression of HDAC6 decreased MPyV infectivity, also decreased infectivity was exhibited by virus isolated from HDAC6 knock out cells. In addition, VP1 protein of virus from HDAC6 knock out cells was more acetylated in comparison with virus from parental cell line. These data suggest that VP1 is substrate for HDAC6. Second part of the thesis is focused on the characterization of N-terminal acetylation of VP3 minor structural protein. It has been previously shown that VP3 protein is N-terminally acetylated and MyPV with mutated (unacetylated) form of VP3 protein is non-infectious. The main aim of this part is to prove the hypothesis that N-terminal acetylation is...
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Polyomavirus minichromosome structure
Satratzemis, Christos ; Forstová, Jitka (advisor) ; Mělková, Zora (referee)
The polyomavirus genome is present in the host cell as circular double-stranded DNA associated with nucleosomes. Consequently, the expression of polyomavirus genes is affected by the location of nucleosomes on DNA and histone modifications. This thesis reviews the current state of knowledge regarding the polyomavirus minichromosome structure and the effects of nucleosome phasing and histone modifications on polyomaviral replication cycle. In addition, factors conditioning these phenomena are discussed. Drawing on available literature, neither nucleosome phasing nor histone modifications appear to be random. However, not all viral DNA molecules are identical in these respects. Processes such as early and late transcription, replication and encapsidation thus occur only within certain fractions of the set of DNA molecules
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Biological treatment and its influence on the course of latent viral infections in patients with psoriasis
Laurin, Josef ; Šmahelová, Jana (advisor) ; Janovec, Václav (referee)
There are more than 80 identified autoimmune diseases. One of the most prevalent ones is psoriasis. Its prevalence is around 2-5 % worldwide. The treatment of this inflammatory skin disease can be divided as follows: in cases of low severity, topical therapies are used for local treatment and in the cases of insufficient effect, stronger therapies are used. Phototherapy is used for moderate severity, and systemic therapy is used in moderate to severe disease. Systemic agents include cytostatic methotrexate, immunosuppressant cyclosporin, or retinoids (vitamin A analogues). However, even systemic therapies may not yield the desired effects or may have adverse effects on the overall condition of the patient. In those cases, biological therapy comes to use. Biological therapy is usually conducted using antibodies and fusion proteins, which are made using recombinant technologies. Tumour necrosis factor α (TNF-α) and interleukin 12, 17 and 23 (IL-12, IL-17 and IL-23) inhibitors are the most commonly used in the treatment of psoriasis. During the inhibition of the immune system, it has been confirmed that a reactivation of viral infections can occur. These reactivations may subsequently lead to the development of various diseases caused by latent viral infections.
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Properties and functions of agnoprotein of polyomaviruses
Zosinčuková, Tereza ; Forstová, Jitka (advisor) ; Vinšová, Barbora (referee)
Polyomaviridae family includes small DNA viruses with simple structure and a small genome encoding only a few proteins. These proteins include large T and small T antigens, as well as 2 to 3 structural proteins known as VP1, VP2 and VP3. In addition, some members of the Polyomaviridae family encode in their genome a small non-structural protein called agnoprotein. Among human polyomaviruses, agnoprotein is present in BK polyomavirus and JC polyomavirus. These viruses are the causative agents of some serious diseases in immunocompromised humans and therefore, they are the subject of intensive research. Simian vacuolating virus 40 is another example of a virus which encodes the agnoprotein. Agnoprotein is capable to manipulate its host cell, disrupt vesicle transport and is also crucial for viral replication and transcription. It appears to play an important role in the morphogenesis of virions and/or in their release from the cell. This paper comprehensively summarizes the latest insights into the properties and functions of the agnoprotein BK polyomavirus, JC polyomavirus and SV40 virus, focusing on the production of this protein during infection, its structure, posttranslational modifications, cell localization, interaction partners and the overall importance of this enigmatic protein for the...
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Targeting of viral nanoparticles to cancer specific receptors
Žáčková Suchanová, Jiřina
The aim of this thesis is to reveal the potential of mouse polyomavirus (MPyV) based virus-like particles (VLPs) as possible nanocarriers for directed delivery of therapeutic or diagnostic compounds to specific cells or tissues. We have chosen mouse polyomavirus VLPs because they do not contain viral DNA and are considered safe for utilization in bio-applications. In our research, we used a chemical approach for retargeting of MPyV based VLPs from their natural receptor to cancer cells. The chemical modification of the capsid surface exposed lysines by an aldehyde-containing reagent enabled conjugation of VLPs to selected molecules: transferrin and inhibitor of glutamate carboxypeptidase II (GCPII). Transferrin, as a transporter of iron to metabolically active cells, targeted VLPs to numerous types of cancer cells overexpressing the transferrin receptor. On the other hand, GCPII serves as a transmembrane marker specific for prostate cancer cells and conjugation of its inhibitor to VLPs resulted in successful recognition of these cells. Electron microscopy was used for visualization of modified VLPs and flow cytometry together with confocal microscopy for investigation of cell specific interactions and VLP uptake. Furthermore, we explored the influence of serum proteins on VLPs. The abundance of...
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Targeting of viral nanoparticles to cancer specific receptors
Žáčková Suchanová, Jiřina ; Španielová, Hana (advisor) ; Němečková, Šárka (referee) ; Ulbrich, Pavel (referee)
The aim of this thesis is to reveal the potential of mouse polyomavirus (MPyV) based virus-like particles (VLPs) as possible nanocarriers for directed delivery of therapeutic or diagnostic compounds to specific cells or tissues. We have chosen mouse polyomavirus VLPs because they do not contain viral DNA and are considered safe for utilization in bio-applications. In our research, we used a chemical approach for retargeting of MPyV based VLPs from their natural receptor to cancer cells. The chemical modification of the capsid surface exposed lysines by an aldehyde-containing reagent enabled conjugation of VLPs to selected molecules: transferrin and inhibitor of glutamate carboxypeptidase II (GCPII). Transferrin, as a transporter of iron to metabolically active cells, targeted VLPs to numerous types of cancer cells overexpressing the transferrin receptor. On the other hand, GCPII serves as a transmembrane marker specific for prostate cancer cells and conjugation of its inhibitor to VLPs resulted in successful recognition of these cells. Electron microscopy was used for visualization of modified VLPs and flow cytometry together with confocal microscopy for investigation of cell specific interactions and VLP uptake. Furthermore, we explored the influence of serum proteins on VLPs. The abundance of...
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