|
|
Transcriptional regulation in the development of the cardiac sympathetic system
Matějková, Kateřina ; Pavlínková, Gabriela (advisor) ; Holzerová, Kristýna (referee)
To improve modern therapeutic and diagnostic methods, it is crucial to understand the development of the cardiac sympathetic system and to identify the genes involved in its regulation. Neural crest cells give rise to the sympathetic precursors that migrate towards the dorsal aorta. This migration is regulated by the NRP1/SEMA3A and neuregulin/ERBB signaling. The differentiation towards the sympathetic phenotype is regulated by transcriptional factor networks, including ASCL1, PHOX2A/B, GATA3, HAND2, HIF1A and ISL1. Next, neurons migrate to the final paravertebral position, which is regulated by the BDNF/TRKB signaling. The final step in the development of cardiac sympathetic neurons is the axon growth and guidance towards the heart. This is regulated by the NGF/TRKA and NRP1/SEMA3A signaling. This thesis aims to map current knowledge of different regulation pathways involved in the cardiac sympathetic development (especially in the mouse model) with emphasis on transcriptional factors. This type of information should help us better understand the pathophysiology of some cardiovascular diseases associated with the dysfunctional sympathetic system, such as arrhythmias, congestive heart failure or myocardial infarction, which remain to be main causes of death worldwide.
|
|
|
Functional role of SOX2 in inner ear neurosensory development
Dvořáková, Martina ; Pavlínková, Gabriela (advisor) ; Rohlena, Jakub (referee) ; Machoň, Ondřej (referee)
The main functional cells of the inner ear are neurons and sensory cells that are formed from a common embryonic epithelial neurosensory domain. Discovering genes important for specification and differentiation of sensory cells and neurons in the inner ear is a crucial basis for understanding the pathophysiology of hearing loss. Some of these factors are necessary not only for the inner ear but also for the development of other neurosensory systems such as the visual and olfactory system. The aim of this work was to reveal functions of transcription factor SOX2 in inner ear development by using mouse models with different conditional deletions of Sox2 gene. Sox2 gene was deleted by cre-loxP recombination. In Isl1-cre, Sox2 CKO mutant, reduced number of hair cells differentiated only in some inner ear organs (utricle, saccule and cochlear base) and not in others (cristae and cochlear apex). Early forming inner ear neurons in the vestibular ganglion and neurons innervating the cochlear base developed in these mutants but died by apoptosis due to the lack of neurotrophic support from sensory cells. Late forming neurons in the cochlear apex never formed. In Foxg1-cre, Sox2 CKO mutant, only rudimental ear with no sensory cells was formed. The initial formation of vestibular ganglion with peripheral and...
|
|
|
Role of ISL1 in development of neurosensory cells of inner ear
Vochyánová, Simona ; Pavlínková, Gabriela (advisor) ; Machoň, Ondřej (referee)
To understand the pathophysiology of hearing loss, it is necessary to identify genes responsible for embryonic development of neurosensory cells in the inner ear. The aim of this work is to clarify the role of LIM-homeodomain transcription factor ISL1 in the development of these cells. Using Cre-loxP recombination strategy, we generated a mouse line with time and site- specific deletion of Isl1 gene in NEUROD1-Cre expressing cells (Isl1 CKO). Although the early development of stato-acoustic ganglion was not affected by Isl1 deletion, at E14,5, we observed abnormalities in neuronal migration, formation of spiral ganglion and axon guidance in the Isl1 CKO cochlea. The length of the cochlear sensory epithelium was shortened by 20% as a consequence of lower proliferation activity of sensory precursor cells. Our results suggest that ISL1 is necessary for spiral ganglion formation and innervation of the Organ of Corti. Key words: transcription factor ISL1, neurons, Cre-loxP system, mouse model
|
|
|
Practical aspects of single-cell RT-qPCR analysis
Žucha, Daniel ; Valihrach, Lukáš (advisor) ; Pavlínková, Gabriela (referee)
Recent breakthroughs in the RNA quantification of single cells are rapidly transforming the view on biology and medicine. Flexibility and sensitivity of reverse transcription quantitative PCR (RT-qPCR) make it an ideal method for quantification of single-cell material, but its limits had not been yet fully explored. In this thesis, various factors influencing RT-qPCR performance in single-cell application have been assessed, including conditions of sample collection and processing, importance of quality control, performance of reverse transcription, preamplification and role of qPCR assays. We showed that prolonged time for single cell collection as well as repeated freeze-thaw cycles had negligible effect on RT-qPCR data quality. Direct lysis routinely applied for RNA extraction from single cells may be scaled up to 256 cells. The comprehensive comparison of 11 reverse transcriptases in low RNA input conditions identified 2 best-performing enzymes. Decrease in preamplification volume as well as poor primer design resulted in the loss of sensitivity. Finally, the established workflow has been applied to profile gene expression of astrocytes in mouse model of amyotrophic lateral sclerosis (ALS) identifying important components of ALS-induced changes to astrocyte transcriptome. Altogether, the thesis...
|
|
|
The development and maintenance of neurons in the inner ear
Wirthová, Natália ; Pavlínková, Gabriela (advisor) ; Pysanenko, Kateryna (referee)
Hearing loss is among the most frequent disabilities. Neurosensory hearing loss is permanent and results from the death of neurons or sensory cells, which have little ability to regenerate in the inner ear (cochlea). Identifying the genes that are associated with generating differentiated and functional sensory cells, neurons, and with hearing loss could provide tools for neurosensory regeneration therapy and preventive measures. Recent data suggest that the prevention of neuronal loss and enhancement of long- term maintenance of neurons are the most important targets for the immediate future. This work is focused on transcription factors and signaling pathway networks that regulate the development and maintenance of neurons in the inner ear.
|
|
|
Possibilities of prediction and immunointervention in type 1 diabetes
Sklenářová, Jana ; Štechová, Kateřina (advisor) ; Saudek, František (referee) ; Pavlínková, Gabriela (referee)
Type 1 diabetes mellitus (T1D) is an organ-specific autoimmune disease characterised by autoimmune destruction of insulin-producing beta cells in the islets of Langerhans. It is a long-term process initiated months or even years prior to the clinical onset. The main role in the pathogenesis is played by T lymphocytes but other cell types are involved as well. The presence of autoantibodies in the circulation is typical even before the disease onset. Nowadays, intensive research is focused on finding individuals at risk and developing an effective prevention. During my postgraduate studies I was involved mainly in the research of T1D prediction and prevention. We investigated the relationship of established autoimmune markers - autoantibodies - and the cellular reactivity to GAD65 and IA2 autoantigens. We discovered that the reaction to autoantigens is very individual and it is influenced by the patient's autoantibody profile. These results could be relevant in planning antigen-specific immunointervention studies and improving their efficacy. We also made an attempt to improve specificity and sensitivity of a beta cell destruction marker (specifically demethylated DNA), which would enable better understanding of the beta cell decline and identification of individuals at risk of T1D development. In...
|
|
|
Molecular mechanisms in transcriptional regulation of neurosensory development
Filová, Iva ; Pavlínková, Gabriela (advisor) ; Tureček, Rostislav (referee) ; Valihrach, Lukáš (referee)
The development, maturation, and viability of inner ear neurosensory cells depend on the spatiotemporal expression of multiple transcriptional factors. Based on three mouse models [Tg(Pax2-Isl1)], Sox2CKO, and Neurod1CKO, this thesis investigates the function of three transcriptional factors ISL1, SOX2 and NEUROD1 in the neurosensory development of the inner ear. The mouse mutant [Tg(Pax2-Isl1)] carries transgenic sequence containing Isl1 gene under Pax2 regulatory sequence in its genome. ISL1 ectopic expression driven by Pax2 regulatory sequence resulted in the enlarged cochleovestibular ganglion and accelerated neurite extension in [Tg(Pax2- Isl1)] embryos. In adult mutants, we detected an early onset of age-related hearing loss correlating with the worsening function of outer hair cells. These changes were associated with the loss of medial olivocochlear efferent neuron fibers innervating outer hair cells. For the first time, we showed that the age-related hearing loss (presbyacusis) might be caused by efferent innervation defects besides hair cell loss and spiral ganglion degeneration. In addition to presbyacusis, [Tg(Pax2-Isl1)] mice suffered from hyperactivity that was diminished by the administration of picrotoxin - channel blocker for GABA receptor chloride channels. This indicates that...
|
|
|
Development and function of endocrine cells of the pancreas
Hamplová, Adéla ; Pavlínková, Gabriela (advisor) ; Berková, Zuzana (referee)
Diabetes mellitus affects nearly 300 million people in the world. The development of diabetes is caused by dysfunction or by reduction of insulin-producing β-cells that are part of the endocrine pancreas. Therefore, the most critical step for understanding the pathophysiology of diabetes and for restoring lost β cells is the identification of molecular cues that specify the cellular phenotype in the pancreas. This work is based on the hypothesis that the transcription factor NEUROD1 is a key factor for the development of the pancreas and for the maintenance of endocrine tissue function. Neurod1 conditional KO mutants (Neurod1CKO) were generated using the Cre-loxP system by crossing floxed Neurod1 mice with Isl1-Cre line. Immunohistochemical analyses of the pancreas at embryonic day 17.5 and postnatal day 0 showed that the deletion of Neurod1 negatively affected the development, organization of endocrine tissue, and total mass of pancreatic endocrine cells. To better understand molecular changes, quantitative PCR was used to analyse mRNA expression in the developing pancreas at the age of embryonic day 14.5 and postnatal day 1. Genes important for the development and function of the pancreas have been selected for the study of expression changes. These analyses showed changes in expression of genes...
|
|
|
Specification and differentiation of cells in pancreatic development
Malfatti, Jessica ; Pavlínková, Gabriela (advisor) ; Horáková, Olga (referee)
Pancreas is divided into exocrine and endocrine tissue. The exocrine part contains acinar cells, which produce digestive enzymes, and ductal cells that help with their transportation to the duodenum. The islets of Langerhans form the endocrine part and consist of 5 types of cells; α, β, δ, ε, and PP-cells, producing hormones glucagon, insulin, somatostatin, ghrelin and pancreatic polypeptide, respectively. Pancreas development is divided into primary, secondary and tertiary transition. Many transcription factors participate in the cell specification and differentiation processes. Pancreatic duodenal homeobox 1 specifies the pancreatic domain in primary transition. Pancreas-specific transcription factor 1A is important for the specification and differentiation of acinar cells. All endocrine cell precursors express Neurogenin 3, a key specification factor of endocrine cells. A large number of transcription factors regulate differentiation of endocrine cells as well as their function. Absence or dysfunction of some transcription factors have been associated with pathologies, for example diabetes mellitus, pancreatic carcinoma or pancreatitis. Key words Pancreas, islets of Langerhans, insulin, glucagon, development, differentiation, diabetes
|
|
|
The effect of maternal diabetes on embryonic cardiovascular development and fetal programing
Čerychová, Radka ; Pavlínková, Gabriela (advisor) ; Nováková, Olga (referee) ; Neckář, Jan (referee)
Maternal diabetes mellitus negatively affects embryonic development and increases the risk for congenital malformations. Besides direct teratogenicity, diabetic intrauterine milieu can predispose an individual to chronic diseases later in life, including cardiovascular diseases, obesity, and diabetes mellitus, in a process termed fetal programing. Molecular mechanisms of embryonic and fetal responses to maternal diabetes are still not fully elucidated. Using mouse model, we show that maternal diabetes induces gene expression changes in the hearts of developing embryos. The most significant changes in the expression of 11 selected genes were detected at the developmental stage associated with completion of cardiac septation, myocardial mass expansion, and increased insulin production in the embryonic pancreas. These affected genes encode products involved in the epithelial-to-mesenchymal transition, a crucial process in heart development. Using immunohistochemistry, we detected increased hypoxia in the diabetes-exposed hearts at the critical stage of cardiac development. Correspondingly to increased hypoxia, the expression of hypoxia-inducible factor 1α (HIF1α) and vascular endothelial growth factor A was increased in the heart of diabetes-exposed embryos. Based on our results indicating the...
|
guest ::
