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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
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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...
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Transcriptional regulation in the development of neurosensory cells in the inner ear
Vochyánová, Simona ; Pavlínková, Gabriela (advisor) ; Schierová, Michaela (referee)
To understand the pathophysiology of hearing loss, it is necessary to identify genes responsible for specification and differentiation of sensory cells and neurons from a common neurosensory progenitor. These factors include LIM-homeodomain transcription factor ISLET1, high-mobility group protein SOX2, and basic helix-loop-helix transcription factors ATOH1, NEUROG1 and NEUROD1. This study aims to map important factors in inner ear development and their interactions with specific focus on transcription factor NEUROD1 and its role in mouse neurosensory inner ear development and function. Key words: inner ear, transcriptional regulation, mouse model, targeted deletion, embryonal development, Neurod1
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Development and function of beta-cells
Hamplová, Adéla ; Pavlínková, Gabriela (advisor) ; Tlapáková, Tereza (referee)
Insulin producing β-cells are located in the endocrine pancreas. They are a part of pancreatic islets of Langerhans along with α-, β-, δ-, ε- a PP-cells producing glucagon, somatostatin, ghrelin and pancreatic polypeptide. Insulin regulates glucose uptake into cells and thus contributes to the regulation of energy metabolism. The development of β-cells as well as the development of the pancreas is a complex process. Developmental processes of proliferation, differentiation and total pancreatic organogenesis are best described in the mouse model. The developmental processes and pancreatic functions are regulated by a network of transcription factors. Pancreatic duodenal homeobox gene 1 is a transcription factor that is expressed in the precursors of endocrine, exocrine and ductal cells. Neurogenin 3 is expressed in precursors of the islets of Langerhans cells. Islet 1 regulates the formation of the islets of Langerhans as well as the pair domains of transcription factors 4 and 6, whose expression is later limited only to β-cells. Transcription factors Islet 1 and Neurod 1 regulate insulin production in β-cells. Mutations in transcription factors lead to the abnormal development and altered function of pancreatic cells, including β-cells. Diabetes mellitus is a disease resulting from defects in...
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The role of Pax6 transcription factor in mouse eye development
Žílová, Lucie ; Kozmík, Zbyněk (advisor) ; Krylov, Vladimír (referee) ; Pavlínková, Gabriela (referee)
The formation of the eye is a multistep process of complex morphogenetic events. It begins with the formation of the optic vesicle (OV) and its subsequent interaction with the overlying head surface ectoderm (SE). Reciprocal interaction between OV and SE evoke lens placode formation within the SE followed by coordinated invagination of both, the lens placode and OV. These events result in formation of lens, retina and retinal pigmented epithelium (RPE) with lens originating from the SE and retina/RPE originating from the OV. Early after the retinal domain is established, retinal progenitor cells start to differentiate in seven retinal cell types that are further stratified in the structure of the retina. The transcription factor Pax6 plays a pivotal role in eye formation in various animal species. In mammals, it is expressed from very early stages of eye development in OV and SE. As Pax6-/- mice are anopthalamic, with eye development arrested at OV/SE stage, much attention has been paid to elucidate the Pax6 function in different eye structures. However, whether and/or how Pax6 regulates the early signaling events leading to eye formation as well as the mechanism by which Pax6 regulates the differentiation of all retinal cell types is still only poorly understood. Using the mouse as a model, we...
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Functional role of ISLET1 in the neurosensory development of the inner ear.
Hampejsová, Zuzana ; Pavlínková, Gabriela (advisor) ; Peterka, Miroslav (referee)
Loss of hearing affects more than 10 % of the population, and one newborn in a thousand is born with defects of the inner ear. Transcriptional factors involved in the development of inner ear are important in our understanding of the causes of inner ear defects. ISLET1 is one of these factors. ISLET1 expression is detected in the sensory and neuronal cells of the inner ear. It participates in otocyst formation, and the specification and differentiation of cells of cochlea and vestibular system. The functional role of ISLET1 during inner ear development was investigated. Its role was studied by using Pax2-Isl1 transgenic mice that overexpress Islet1 under the control of the Pax2 promoter. Two transgenic lines were generated, Pax2-Isl1/300 and Pax2- Isl1/52. Two copies of the Pax2-Isl1 transgene were inserted to Pax2-Isl1/300 genome and one copy was inserted to the Pax2-Isl1/52 genome. Defects in sense of hearing were detected in both lines and circling behavior, a defect of balance, was detected in the Pax2-Isl1/300 transgenic mice. We observed high postnatal lethality in heterozygote transgenic mice. Pax2-Isl1/52 homozygote mutation is lethal at embryonic day 10 (E10,5). Pax2-Isl1/300 homozygote letality couldn't be detected because of the inability to breed heterozygote mutated mice of this line....
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Changes in embryonal programing induced by diabetes mellitus
Landsmann, Lukáš ; Pavlínková, Gabriela (advisor) ; Tlapáková, Tereza (referee)
Embryonic development is sensitive to environmental changes. These changes may lead to changes in the embryonic programming. Changes in programming embryos can occur due to inadequate nutrition, stress, treatment with chemicals and also due to diabetes. Epigenome reacts sensitively to environmental factors regulating gene transcriptional activity. Changes in the epigenome lead to a changes in gene expression, which can have a negative impact on the physiology and metabolism of organism. Maternal diabetes may alter embryonic and fetal development and may result in diabetic embryopathy. Furthermore, maternal diabetic enviromental plays an important role in the predisposition of offspring to a number of chronic diseases later in life. The offspring of diabetic pregnancies demonstrate differences in metabolic, cardiovascular, and inflammatory variables, compared to the offspring of nondiabetic mothers. This thesis summarizes the genetic and epigenetic factors involved in the development of diabetic embryopathy and in the embryonic programming. Key words: Diabetes mellitus, diabetic embryopathy, transcriptional regulation, genetic and epigenetic factors , embryonic programming, genome
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Molecular mechanisms in diabetic embryopathy
Čerychová, Radka ; Pavlínková, Gabriela (advisor) ; Kolář, František (referee)
Diabetic embryopathy is one of many serious complications associated with diabetes. It is known that maternal diabetes increases the frequency of congenital defects up to ten times. The most common defects are cardiovascular and neural tube defects. Molecular mechanisms of diabetic embryopathy are still not known. This work contributes to elucidation of molecular processes leading to development of cardiovascular defects in diabetic embryopathy. This study is based on observation that maternal diabetes affects transcriptional regulation of hypoxia-inducible factor 1 (HIF-1) in developing embryo. To study the influence of maternal diabetes on HIF-1 signaling pathway, we used mouse model heterozygous for "knock-out" of Hif1α gene. Our analyses showed the negative combinational effects of maternal diabetes and Hif1α+/- genotype on embryonic development and increased risk of diabetic embryopathy. Histological analysis demonstrated the increased incidence of cardiovascular defects, particularly defects of interventricular septum and hypoplastic compact left ventricular wall in embryonic day (E) 14.5 Hif1α+/- embryos compared to wt littermates from the diabetic pregnancy. Using qPCR, we analyzed gene expression changes in the embryonic hearts at E9.5 and E10.5. We selected genes important for the...
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Cardioptrotective role of transcription factor HIF isoforms in rats
Bučinská, Ivana ; Žurmanová, Jitka (advisor) ; Pavlínková, Gabriela (referee)
Adaptation to chronic hypoxia is characterized by a variety of functional changes in order to maintain metabolic and energy homeostasis. It has been known for many years that both humans and animals indigenous or adapted to high-altitude hypoxia are more tolerant to an acute ischemic injury of the heart. HIF1α is found as a primary transcriptional regulator of adaptive response to hypoxia in all tissues, whereas HIF2α is more tissue specific. The activity of HIFα is regualted by prolyl hydoxylases (EGLN). The EGLN1 was shown to be more efficient in HIF1α hydroxylation than in HIF2α. As well as the EGLN3 is more specific for HIF2α . Under hypoxic conditions, HIF activates the transcription of about 70 genes. Hence, HIF1α and HIF2α can play an essential role in pathophysiology of ischemic heart disease. The aim of our study was to determine myocardial expression of HIFs and its regulatory hydroxylases in adult male Wistar rats adapted to continuous normobaric hypoxia (H; FIO2 = 0.1) for 3 weeks. Another two groups of rats were exposed to normobaric hypoxia intermittently for either 8 h/day (INH) or 23 h/day (RH) during the 3-week adaptation period. While H induces protective cardiac phenotype, the later regimen (RH) does not. The protein expression of HIFs, PHDs and FIH were then determined by...
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The role of Wnt signaling in embryonic development.
Dupačová, Naoko ; Kozmík, Zbyněk (advisor) ; Peterka, Miroslav (referee) ; Pavlínková, Gabriela (referee)
Ph.D. thesis: The role of Wnt signaling in embryonic development Naoko Dupačová (Fujimura) ABSTRACT Wnt signaling plays important roles in multiple developmental processes. The binding of Wnt ligands to their receptors and coreceptors activates three main downstream pathways: canonical Wnt/β-catenin signaling, which results in the activation of β-catenin/Tcf mediated gene expression and noncanonical Wnt/PCP and Wnt/Ca2+ pathways. In this thesis, we aimed at studying the role of Wnt/β-catenin signaling during embryonic development, especially in the telencephalon and the eye. Wnt/β-catenin signaling is essential for the maintenance of proliferation of neuronal progenitor cells and dorso-ventral specification during the telencephalon development. To provide further insights, we studied transcriptional targets of canonical Wnt signaling. We show that the ectopic activation of Wnt/β-catenin signaling results in the up-regulation of Sp5 gene, which encodes a member of the Sp1 transcription factor family. A proximal promoter of Sp5 gene contains five Tcf/Lef binding sites that mediate direct regulation of Sp5 expression by canonical Wnt signaling. We further provide evidence that Sp5 works as a transcriptional repressor. Finally, our data strongly suggest that Sp5 has the same DNA binding specificity as Sp1 and...
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