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Fumarate hydratase as tumor suppressor
Kedrová, Kateřina ; Hansíková, Hana (advisor) ; Befekadu, Asfaw (referee)
1 Abstract Fumarate hydratase (fumarase, EC 4.2.1.2) catalyzes the reverse hydration of fumarate to S malate. In mammalian cells, it changes fumarate in the mitochondrial matrix as a part of the citric acid cycle and in the cytosol, where functions to metabolize fumarate the product of the degradation of some amino acids, of ammonia transformation to urea acid or of the purine nucleotide synthesis. . In human cells, fumarase is encoded by FH gene localized on chromosome 1 (1q42.1). The FH gene consists of 10 exons and encodes for a 510 amino acids-long protein including the N-terminal mitochondrial signal sequence. Germline heterozygous FH mutations were found in two autosomal dominant syndromes. These are multiple cutaneous and uterine leiomyomatosis (MCUL1 or MCL) and hereditary leiomyomatosis and renal cell cancer (HLRCC). In the most of tumors from these patients, loss of FH gene heterozygosity was also found. It has been suggested that fumarase acts as a tumor suppressor according to Knudson's two-hit hypothesis. The aim of the bachelor thesis was to study the activity and amounts of fumarase in a series of 22 samples of uterine leiomyomas from 22 young women patients (21-31 years) with sporadic uterine leiomyomas. As a control sample, uterine leiomyoma from a 38-year-old patient was used. Activity of...
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Study of mitochondrial ultrastructure and functions in selected mitochondrial and lysosomal storage disorders
Kostková, Olga ; Hansíková, Hana (advisor) ; Šmíd, František (referee) ; Hyánek, Josef (referee)
This thesis has been worked out in The laboratory for study of mitochondrial disorders (Departement of Pediatrics, 1st Faculty of Medcine, Chales university in Prague) and in cooperation with The Institute of Inherited Metabolic Disorders. Mitochondrial disorders represent a heterogeneous group of diseases with the onset at any age from neonatal period till adulthood, mostly presented with very severe clinical courses of disease. The mammalian organism is fully dependent on mitochondrial oxidative phosphorylation system as on the major energy producer of the cell. Therefore the mitochondrial disorders affect mainly high energy demanded tissues such as brain, heart or muscle. Simillar phenotype is observed in many lysosomal storage disorders. Despite of expanding knowledge of molecular basis of mitochondrial and lysosomal disorders, it may be still difficult to explain the exact pathogenesis of disease as well as the prognosis for patients and their families. Mitochondrial functions affect more than just energy production; they contribute in initiation of apoptosis, in cellular calcium homeostasis, and in production of reactive oxygene species. Disturbed mitochondria become a goal of autophagy mediated by the lysosomal compartement. The results of our study enable: 1. better understanding of the tissue...
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Flow cytometry in the diagnostics and characterization of congenital disorders of glycosylation
Veselá, Šárka ; Hansíková, Hana (advisor) ; Hodek, Petr (referee)
Congenital disorders of glycosylation (CDG) are rare multisystem metabolic diseases and their number has rapidly grown in recent years. The clinical manifestation includes very broad spectrum of symptoms. In most of all cases CDG are caused by mutations in genes encoding the enzymes of glycosylation pathway. Based on the type of defect, CDG are divided into the following groups: disorders of N-glycosylation or O-glycosylation of proteins, defects in modification of proteins by GPI anchor, disorders of lipid glycosylation and defects that impact multiple glycosylation pathways. The aim of the thesis was to find new biochemical analyses suitable for diagnostics and characterization of CDG patients. The experimental conditions were optimized for selected markers (Sambucus Nigra (SNA) lectin, proaerolysin (FLAER), antibodies to proteins CD55 and CD59) and the staining was applied to cultivated skin fibroblasts from controls and patients diagnosed with CDG by whole-exome sequencing (ATP6AP1-CDG, PIGN-CDG, SLC10A7-CDG, PISD deficiency). The experiments were performed using flow cytometry (FACS) and fluorescent microscopy (FM). The detection of sialylation by SNA lectin and analysis of the mitochondrial membrane potential changes by a fluorescent labelled probe JC-1 with FCCP simulation of mitochondrial...
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Biochemical and molecular studies of the congenital disorders of glycosylation
Ondrušková, Nina ; Hansíková, Hana (advisor) ; Stiborová, Marie (referee) ; Hřebíček, Martin (referee)
Congenital disorders of glycosylation (CDG) represent a rapidly growing group of rare inherited metabolic diseases with estimated prevalence as high as 1:20 000, which are caused by genetic defects that impair the process of glycosylation, i.e. the enzymatic addition of a specific saccharide structure onto a protein or lipid backbone. Due to non-specificity and variability of clinical symptoms in the patients, the medical diagnosis of CDG remains extremely challenging and significantly relies on accurate biochemical and genetic analyses. The overall goal of the present dissertation thesis was to study CDG at the biochemical and molecular genetic level in the context of the Czech and Slovak Republic, which involved three specific aims: A.) to introduce and optimize laboratory screening methods for CDG detection in a group of clinically suspected patients, B.) to determine the corresponding genetic defect in the positive patients selected via CDG screening and to study the pathobiochemical aspects of specific CDG types at the cellular level, and C.) to analyze glycosylation disturbances of non- CDG etiology. Contributions of this work include optimization of isoelectric focusing of apolipoprotein C-III (ApoC-III) as a screening method for O-glycosylation abnormalities, as well as the description of...
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Mitophagy in Huntington's Disease
Šonský, Ivan ; Hansíková, Hana (advisor) ; Macůrková, Marie (referee)
Mitochondrial dysfunctions contribute to the progression of many neurodegenerative diseases, including Huntington's disease (HD). In HD, mutation in the huntingtin gene (HTT) results in the expansion of CAG repeats, causing the growth of the polyglutamine tract. This growth is responsible for the gain of toxicity function of the protein. The turnover of dysfunctional and damaged mitochondria is mediated via mitophagy - a selective form of autophagy. Additionally, mitophagy impairments have recently been described to play a key role not only in neurodegenerative diseases. The protrusion of mitophagy results in the clustering of defective mitochondria, organelles which are responsible for fulfilling the energetic demands of neural cells. The most distinctive impact of the impairment is on the striatal medium spiny neurons and results in the development of motor and cognitive dysfunctions. This thesis describes how HD affects mitophagy and reveals the biggest obstacle of mitophagy - disruption of mitochondria targeting into emerging autophagosomes caused by the abnormal interaction of mHTT and p62. Induction of mitophagy at this stage could be crucial for the future therapeutic research of HD. Generally, initiation of mitophagy could become a relevant therapeutic target for many other...
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Mitochondrial permeability transition pore
Sereghy, Ursula ; Hansíková, Hana (advisor) ; Čapková, Markéta (referee)
The mitochondrial permeability transition pore (mPTP) is highly evolutionarily conserved channel found in the inner membrane of mitochondria. This pore is non-selectively permeable for molecules below 1,5 kD. Consequences of the pore opening due to an increase of Ca2+ or reactive oxygen species (ROS) and following depolarization of the membrane involve a disruption of the proton gradient, decrease in the production of ATP and prevalently a cell death. Death of a cell as a result of the mPTP opening is a physiopathological mechanism which follows ischemic diseases and neurodegenerative disorders such as Alzheimers and Huntingtons disease. Study of a structure and function of mPTP is essential for the research of mechanisms and progression of diseases, and it is crucial for the development of responding drugs and an overall decrease in the morbidity of the patients. This work compiles the course of the research into structure and function of the channel under physiological and pathological conditions and briefly puts down some of the experimental methods.
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Study of selected apects of protein modification by β-N-acetylglucosamine
Bittenglová, Kateřina ; Hansíková, Hana (advisor) ; Kohoutová, Michaela (referee)
Glycosylation O-linked β-N-acetylglucosamine (O-GlcNAc) is post-translational modification of proteins, regulated by β-N-acetylglucosaminyltransferase (OGT) and β-N-acetylglucosaminidase (OGA). This intracellular glycosylation differs from the other glycosylation types - it is dynamically regulated, similarly to phosphorylation, β-N-acetylglucosamine serves as a nutrient and stress sensor in cell. Chronically dysregulated O-linked glycosylation by GlcNAc is associated with pathology of various diseases, such as diabetes mellitus type II, oncological and neurodegenerative diseases. Expression of enzymes OGT and OGA is very sensitive for homeostasis of GlcNAc, which is the product of hexosamine biosynthetic pathway. Changes in expressions of these ezymes could be used as a potencial blood marker, e.g. in early stage of diabetes. The aim of this master thesis was to study changes in expression of genes encoding ezymes OGT and OGA in cohort of obese patients in comparison with healthy controls and also to compare the state before and after change of lifestyle (loosing weight). Analysed cohort comprised of 34 samples of isolated lymphocytes from peripheral blood from obese adolescent patients and 80 samples of adults patients. RNA was isolated by TriReagent, quantification of the expression of mRNA was...
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Dolichol content analysis by mass spectrometry in urine from patients with congenital disorders of glycosylation
Zdražilová, Lucie ; Hansíková, Hana (advisor) ; Kohoutová, Michaela (referee)
Dolichol is a membrane lipid, which carries monnosaccharides and glycans for N-linked protein glycosylation and glycosylphosphatidylinositol-anchor biosynthesis occuring in endoplasmic reticulum. Its structure is composed of isoprenoid units. Dolichol is present in all tissues and in most of the membrane organelles of eukaryotic cells. Recently some types of congenital disorders of glycosylation have been described as a consequence of dolichol biosynthesis and metabolism defects, which are not detectable by standard methods. The aim of this diploma thesis was to analyze dolichol content in urine and in different tissues from patients with deficiency in dolichol biosynthesis by mass spectrometry and to study the impact of these defects on energetic metabolism. Biological material for this study consisted of urine samples from 76 controls with age ranging from 1 months to 81 years, 6 patients with congenital disorders of glycosylation and 43 patients with suspicion of congenital disorder of glycosylation; samples of frontal cortex, liver, muscle and heart tissues from 2 patients with mutation in NUS1 gene and controls. Urine samples were stored at -20 řC and tissue homogenates were stored in -80 řC until analysis. Lipid fraction after extraction was separated by liquid chromatography. Dolichols were...
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Following the phenotype development of TgHD minipigs by invasive and noninvasive approach
Ellederová, Zdeňka ; Baxa, Monika ; Vidinská, Daniela ; Bohuslavová, Božena ; Vochozková, Petra ; Šmatlíková, Petra ; Klíma, Jiří ; Valeková, Ivona ; Ardan, Taras ; Juhás, Štefan ; Juhásová, Jana ; Konvalinková, R. ; Klempíř, J. ; Pokorný, M. ; Krupička, R. ; Kauler, J. ; Hansíková, H. ; Motlík, Jan
Recent promising treatments for Huntington’s disease (HD) may require pre-clinical testing in large animals. In 2009, we generated HD transgenic (TgHD) minipigs with one copy encoding the N-terminal part (548 aa) of human huntingtin (HTT) with 124 CAG/CAA repeats integrated into chromosome 1 q24-q25. The successful germ line transmission occurred through four successive generations.
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Mitochondrial phenotype in minipig model transgenic for N-terminal part of human mutated huntingtin
Hansíková, H. ; Rodinová, M. ; Křížová, J. ; Dosoudilová, Z. ; Štufková, H. ; Bohuslavová, Božena ; Klíma, Jiří ; Juhás, Štefan ; Ellederová, Zdeňka ; Motlík, Jan ; Zeman, J.
Huntington’s disease (HD) is neurodegenerative disorder caused by an abnormal expansion of CAG repeat encoding a polyglutamine tract of huntingtin (htt). It has been postulated that mitochondria dysfunction may play significant role in the pathophysiology of the HD. But it is still not known yet in detail how mitochondria are able to cover energy needs of the cells during the progression of the HD.
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