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Conservation genetics of Galápagos mockingbirds: from immune genes to genomes
VLČEK, Jakub
In this thesis I have dealt with the population genetic processes of mockingbirds in the Galápagos Islands ( Mimus ) in relation to the limited island area, from the perspective of two types of immune genes and the genome-wide approach. The thesis starts with an introduction to population genetic concepts relevant to conservation genetics followed by description of immune genes: the major histocompatibility complex (MHC) and the Toll-like receptors (TLR). In the final part of the introduction, I address how genetic drift, selection and inbreeding shape genome-wide genetic patterns in small populations. The introduction is followed by four chapters, beginning with an examination of MHCII polymorphism in populations of mockingbirds in the Galápagos Islands. The study of the relationship between MHCII and the abundance of ectoparasites is the content of the second chapter. The third chapter shows how polymorphism of TLRs is shaped by interaction of genetic drift and natural selection. The last chapter deals with the effects of limited island size on inbreeding and genetic load, supported by inferences of the past demography of mockingbirds. The thesis concludes with a summary of the results and their potential implications in the field of conservation genetics.
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Targeting IRAK4 kinase in autoimmune diseases and cancer
Synáčková, Alžběta ; Dráber, Peter (advisor) ; Brdička, Tomáš (referee)
Immune system provides host protection against invading pathogens. However, aberrant activation can lead to development of autoimmune diseases or cancer. Understanding the mechanisms of inflammation and immune responses is crucial for treatment of such conditions and reestablishing immune balance. Toll-like receptors and interleukin-1 family receptors are a key component of the innate immune system. Their downstream molecules, MyD88 and IRAK4, are essential for receptor signaling as their deficiency causes host susceptibility to infection. On the other hand, overactivation of this pathway was shown to be able to promote autoimmunity and cancer. The main focus of this text will be to summarize current knowledge about the mechanism of IRAK4 signaling and how it can be exploited in the development of therapeutics. Keywords IRAK4, MyD88, Toll-like receptors, IL-1 receptor, cytokines, autoimmunity, cancer
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Role of peripheral blood monocytes and innate immunity in diabetes
Zinková, Alžběta ; Daňková, Pavlína (advisor) ; Novota, Peter (referee)
Introduction: Diabetes mellitus is a polygenic disease and its development is influenced to some extent by environmental factors as well. Innate immunity triggers nonspecifically first defense reactions after penetration of the pathogen into the body, while overstimulation components of innate immunity may give rise to autoimmune diseases, including diabetes type 1. The components of innate immunity are, among others, Toll-like receptors (TLRs) belonging to a group of the structures recognizing preserved molecular structures characteristic of pathogens. Toll-like receptors are abundantly expressed by monocytes which produce prolactin (PRL) having an immunostimulatory function. To clarify the role of innate immunity in the pathogenesis of diabetes, we focused on the expression of mRNA and protein expression of TLR2 and TLR4. The expression of PRL was studied only at the level of mRNA. Monocytes were separated by flow cytometry into classical (CD14++) and nonclassical (CD14+). We monitored their percentages and the degree of expression of CD14 antigen on their surface.The operational objective of this dissertation was to optimize the stimulation of monocytes for the planned study of the function of non-pituitary prolactin in vitro and determine the appropriateness of the use of healthy donors' buffy...
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Role of toll-like receptors and stress hormone prolactin in defects of immune system
Sluková, Veronika ; Daňková, Pavlína (advisor) ; Hušáková, Markéta (referee)
Introduction: Diabetes mellitus is a polygene disease and on its manifestation have influence also enviromental factors. We have studied the role of extrapituitary prolactin (PRL) and toll-like receptors (TLR) 2 and 4 in the etiopathogenesis of autoimmune diabetes. PRL is mainly produced by hypophysis, but in small concentrations also in the periphery, where it participates in the immune reactions. Therefore, we investigated the influence of the levels of monocytic PRL mRNA on the development of diabetes, and also the influence of G allele of the -1149 G/T polymorphism in the extrapituitary promotor, which has already been associated with other autoimmune diseases. TLRs are receptors of the immune cells that recognize patogenes entering into the body. They play an important role in the iniciation of the immune response. We aimed to find out their function in the pathogenesis of the autoimmune diabetes by the detection of their mRNA levels and protein levels expressed on the cell surface of the monocytes. Material and methods: In this study we included 30 T1D and 21 LADA patients. Three control groups consisted of 23 T2D patients, 23 patients with a nondiabetic disease (neDM) and 60 healthy blood donors (TO). Blood samples have been taken from the individuals. From these blood samples we isolated...
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Toll like receptors and myeloid cells in development and disease
Balounová, Jana ; Filipp, Dominik (advisor) ; Špíšek, Radek (referee) ; Vannucci, Luca Ernesto (referee)
Toll like receptors (TLRs) are germline-encoded pattern recognition receptors (PRRs) that play a central role in host cell recognition and responses to pathogens. Primarily they are responsible for induction and regulation of the innate and adaptive immune responses whereby the effector function is executed chiefly by differentiated myeloid cells. Somewhat unexpectedly, TLRs have been also shown to be involved in direct pathogen sensing by bone marrow-derived hematopoietic stem cells (HSCs) and hematopoietic progenitors when, under inflammatory conditions, the rapid generation of innate immune effector cells that effectively combat the infection is of utmost priority. While it has been recognized that the release of inflammatory cytokines from inflamed tissues along with the changes in proportions of differentiating cells in the bone marrow (BM) as well as the BM niche can nudge the differentiation of adult BM-derived cells towards myeloid cells and granulocytes, a direct role of TLRs expressed by HSCs in this process has been demonstrated only recently. However, whether a similar mechanism operates also during embryonic hematopoiesis is unknown. Here we show that TLRs and their adaptor proteins are functionally expressed during early stages of embryogenesis by short-lived maternally-transferred...
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Physiological role of SIGIRR in early embryonic development.
Hanusová, Zdeňka ; Filipp, Dominik (advisor) ; Brdička, Tomáš (referee)
IL-1 receptor/Toll-like receptor (IL-1R/TLR) supefamily represents a group of proteins that share highly conserved TIR domain in their cytoplasmic region. Signal transduction mediated by TIR-containing proteins involves the activation of NF-κB transcription factor and thus the members of this superfamily play a key role in many physiological responses related to innate immune defense and inflammation. SIGIRR (single immunoglobulin IL1R-related molecule) is a recently discovered member of the IL-1R family, however it differs from the other group members by its unique structural features. SIGIRRhas been so far considered to be an 'orphan' receptor as no SIGIRR ligand has been identified yet. Moreover, SIGIRR itself is not capable to induce the NF-κB activation. Instead, SIGIRR is supposed to act as a negative regulator for IL- 1Rs/TLRs mediated inflammation. Its inhibitory function has been implemented in several signalling pathways in various cell types and tissues including the kidney, the digestive tract and the lung. Recent reports also suggest that SIGIRR could play a role in early embryonic development. The main aim of this thesis is to characterize the mechanism how SIGIRR negative regulatory function in IL-1R/TLR signalling pathway is delivered. Here we describe the establishment of...
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AIRE-expressing cells in immune tolerance in health and disease
Vobořil, Matouš ; Filipp, Dominik (advisor) ; Černý, Jan (referee) ; Ehrlich, Lauren Ilyse Richie (referee)
The process of self-nonself discrimination by the immune system is a fundamental attribute of healthy organisms. Since T-cell receptors (TCRs) are generated by the random process of somatic recombination without regard to its targets, the newly developed T-cell clones could recognize either self or nonself antigens. The mechanisms of central tolerance robustly limit the self-reactive repertoire within the T-cell population via deletion of clones that express self-reactive TCRs or their deviation into the regulatory T-cells (Tregs). These processes occur mainly in the thymic medulla where the TCR reactivity to self-antigens is tested by various types of antigen-presenting cells, mainly medullary thymic epithelial cells (mTECs), dendritic cells (DCs), and B-cells. The cooperation between these cell-types has been shown to be essential for the establishment of thymic tolerance. A key molecule regulating the production of self-antigens is the autoimmune regulator (AIRE), which is thought to be expressed primarily by mTECs and its mutations are associated with the development of severe autoimmune disorders. In this context, the presented thesis describes the novel regulatory pathways important for the development of a functional and "harmless" repertoire of T-cells and for enforcement of tolerance....
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The utility of Toll-like receptor 2 in defining the progenitors of definitive embryonic hematopoiesis
Šplíchalová, Iva ; Filipp, Dominik (advisor) ; Nečas, Emanuel (referee) ; Kalina, Tomáš (referee)
Hematopoiesis is a vital process in which red blood cells and cells of the immune system are formed. It is initiated during early embryonic development when we find hematopoietic progenitors in separate anatomical sites. Embryonic hematopoiesis comprises three successive and partly overlapping waves of progenitors with a different hematopoietic potential. The primary anatomical place where hematopoiesis takes place shortly before the birth is the bone marrow (BM). Since at this time point of development BM is already populated by hematopoietic stem cell (HSCs) progenitors, it becomes also the site of hematopoiesis in adulthood. However, the bone marrow is not the only place where hematopoietic progenitors emerge and develop. The Yolk sac (YS) and the Aorta-Gonad-Mesonephros (AGM) region are the initial sites of the appearance of the three waves of progenitors in the early embryogenesis. These progenitors and their descendants play an indispensable role during the development of an individual. Because there are no specific markers that would unambiguously characterize progenitors of these individual waves, their physical separation and hence also functional characterization is still incomplete. Recent studies have shown that Toll-like receptors (TLRs) are expressed on adult HSCs. The stimulation of...
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Interaction of hepatitis B virus proteins with mechanisms of innate immunity
Vávrová, Petra ; Hirsch, Ivan (advisor) ; Horníková, Lenka (referee)
Specific aim of this bibliographic research is to elucidate interaction of hepatitis B virus proteins with mechanisms of the innate immunity. The work will specially analyze the role of viral proteins before and after their transport from the infected cell. Because of the central role of cccDNA for virus persistence in human organism, the work will study the effects of restriction factors on its possible destruction and eradication. The research will be focused on the effect of viral proteins during acute, chronic and occult infection.
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Interactions of mouse polyomavirus with Toll-like receptors
Pokorná, Karolína ; Forstová, Jitka (advisor) ; Němečková, Šárka (referee)
Toll-like receptors (TLRs) are important receptor family of innate immunity. They enable fast recognition of infection through so called pathogen associated molecular patterns (PAMPs). In this thesis, we studied interaction of mouse polyomavirus (MPyV) with TLRs of mouse embryonic fibroblasts (MEF cells). We observed that inhibition of TLR4 signaling abolished response of MEF cells to MPyV. This suggested that TLR4 plays a role in MEF cells recognition of MPyV. To detect response of MEF cell to MPyV, we measured IL-6 production by ELISA. Next, we investigated effect of TLR4 signalization on MPyV infection. Inhibition of TLR4 signaling with CLI-095 inhibitor did not affect number of infected cells. Presence of TLR4 antagonist, LPS-RS, led to significant decrease in quantity of infected cells 20 hours post infection. Decrease in number of infected cells was also observed in presence of LPS. Viral infection was also inhibited by TLR9 antagonist ODN 2088. We also investigated role of MAP kinases in MPyV infection. We tested, whether inhibition of selected MAP kinases would affect number of infected cells. Inhibition of kinase p38 did not affect infection. On the other hand, inhibition of MEK kinase or JNK resulted in decrease of number of cells infected by MPyV.
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