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Study of etiopathology of mitochondrial disorders
Rákosníková, Tereza ; Tesařová, Markéta (advisor) ; Pecina, Petr (referee) ; Kalous, Martin (referee)
Mitochondrial disorders are a clinically, biochemically and genetically heterogeneous group of inherited disorders with a prevalence of about 1:5 000 live births. A common sign of those disorders is disruption of mitochondrial energetic metabolism. To this day, more than 400 genes have been associated with mitochondrial disorders, but 45% of patients are still without a genetic diagnosis. Using next-generation sequencing, new candidate genes or variants are found. To confirm the causality of those newly found genes or variants, biochemical characterisation using a plethora of various methods is necessary. The first aim of this thesis was to study the function of ACBD3 protein on mitochondrial energetic metabolism in non-steroidogenic cells HEK293 and HeLa and to confirm the causality of the ACBD3 gene in a patient with combined oxidative phosphorylation (OXPHOS) deficit. The second aim was to confirm the causality of two novel variants in MT-ND1 and MT-ND5 genes, which encode structural subunits of complex I (CI) of the respiratory chain. The third aim of the thesis was to study the formation of supercomplexes (SCs) in patients with rare metabolic diseases. Using functional studies, we showed in this thesis that ACBD3 protein has no essential function in mitochondria but plays an important role in...
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Hereditary Mitochondrial Disorders Caused by Oxidative Phosphorylation Disfunction
Hanušová, Eva ; Ehler, Edvard (advisor) ; Pavlasová, Lenka (referee)
Hereditary Mitochondrial Disorders Caused by Oxidative Phosphorylation Dysfunction This bachelor thesis deals with problems of hereditary mitochondrial disorders that are caused by various dysfunctions of proteins in oxidative fosforylation known as OXPHOS complex. Following recherche provides the reader with information about the genom and the structure of mitochondria where the OXPHOS is realized and about its structure and progress. I describe basic facts about various mutations in nuclear and mitochondrial DNA that negatively affect function of OXPHOS complex and the biogenesis of mitochondria. The focus of this work is to summarize the newest data of individual diseases - their clinical manifestation, etiopatogenesis, prevalance in population and its possible treatment and prevention. Key words: hereditary, mtDNA, mitochondrial diseases, OXPHOS complex
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Human F1Fo-ATPsynthase deficiency
Suldovská, Sabina ; Tesařová, Markéta (advisor) ; Černá, Leona (referee)
F1FO-ATPsynthase is a key enzyme in energy metabolism of the cell. Its deficit is caused usually by mutations in two structural genes MT-ATP6 and MT-ATP8 encoded by the mitochondrial DNA or in nuclear genes ATPAF2 and TMEM70 encoding the biogenesis factors and structural gene ATP5E. Deficiency of the F1FO-ATPsynthase leads to progressive and serious phenotype affecting organs with high energy demands. The first symptoms usually occurs in neonatal age and prognosis of the disease is fatal. Mutations in these genes result in both qualitative and quantitative defects of the F1FO-ATPsynthase. The study of molecular bases of mitochondrial disorders including F1FO-ATPsynthase deficiency uses large number of biochemical and molecular-genetic methods to determine a proper diagnosis which is essential for the symptomatic therapy and genetic counselling in affected families. The aim of the diploma thesis was to characterise the F1FO-ATPsynthase deficiency in isolated mitochondria from the lines of cultured cells by the determination oligomycin- sensitive ATP-hydrolytic activity of the F1FO-ATPsynthase, enzymatic activities of the respiratory chain complexes and to analyse changes in the steady-state levels of the representative subunits and whole complex of the F1FO-ATPsynthase in comparison with controls. 3...
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Mitochondrial ATP synthase deficiencies of a nuclear genetic origin
Karbanová, Vendula ; Houštěk, Josef (advisor) ; Kalous, Martin (referee) ; Rossmeisl, Martin (referee)
ATP synthase represents the key enzyme of cellular energy provision and ATP synthase disorders belong to the most deleterious mitochondrial diseases affecting pediatric population. The aim of this thesis was to identify nuclear genetic defects and describe the pathogenic mechanism of altered biosynthesis of ATP synthase that leads to isolated deficiency of this enzyme manifesting as an early onset mitochondrial encephalo-cardiomyopathy. Studies in the group of 25 patients enabled identification of two new disease-causing nuclear genes responsible for ATP synthase deficiency. The first affected gene was TMEM70 that encodes an unknown mitochondrial protein. This protein was identified as a novel assembly factor of ATP synthase, first one specific for higher eukaryotes. TMEM70 protein of 21 kDa is located in mitochondrial inner membrane and it is absent in patient tissues. TMEM70 mutation was found in 23 patients and turned to be the most frequent cause of ATP synthase deficiency. Cell culture studies also revealed that enzyme defect leads to compensatory-adaptive upregulation of respiratory chain complexes III and IV due to posttranscriptional events. The second affected gene was ATP5E that encodes small structural epsilon subunit of ATP synthase. Replacement of conserved Tyr12 with Cys caused...
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Non-pharmacological approaches towards treatments of mitochondrial disorders
Kudrnovská, Barbora ; Mráček, Tomáš (advisor) ; Kalous, Martin (referee)
Mitochondrial diseases are characterized by a high degree of genotypic and phenotypic heterogeneity, but as a whole group, they represent one of the most common forms of inborn errors of metabolism. Treatment of these diseases is still very limited, despite massive body of ongoing research projects, which are focussed on new therapeutic approaches. Besides pharmacological methods, there are also non-pharmacological approaches such as certain diet regimens, physical activity or exposition to hypoxia. Due to their relatively generalized mechanism of action, these methods may offer benefits to a wider range of mitochondrial patients, despite different primary genetic defects. This work summarizes the existing knowledge about the use of exercise, ketogenic diet, and hypoxia application as possible therapeutic approaches towards the treatment of mitochondrial diseases. Keywords: mitochondria, mitochondrial diseases, therapy, exercise, ketogenic diet, hypoxia
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Význam laktátu v diagnostice mitochondriálních onemocnění u dětí
Magner, Martin ; Zeman, Jiří (advisor) ; Baxová, Alice (referee) ; Procházková, Dagmar (referee)
The lactate level assesment in various body fluids plays an important role in the diagnostics of mitochondrial disorders in children. However, the interpretation of lactate level is often difficult due to its unspecificity and variability even in particular mitochondrial disorders. Three specific aims have been stated in this PhD Thesis: 1. To analyse the role of lactate examination in the differential diagnosis between children with mitochondrial disorders and children with other diseases. 2. To study the lactate level differences in various mitochondrial syndromes. 3. To characterise the clinical and laboratory data of neonates with mitochondrial disorders and to suggest new diagnostic algorhytms. Clinical and laboratory data from patients hospitalized in the Department of Pediatrics were collected. Laboratory methods were provided in the cooperation with the Mitochondrial laboratory of the Department of Pediatrics and Institute of Inherited Metabolic Disorders. The study with lactate levels in 107 patients documented that brief seizures lasting less than 2 minutes did not increase lactate concentration in the CSF. CSF-lactate was a relialable marker in differential diagnosis in the children with mitochondrial disorders against children with epilepsy. 2. The severity of particular phenotype is more...
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Genetic and functional characterisation of mitochondrial diseases caused by ATP synthase defects
Tauchmannová, Kateřina ; Houštěk, Josef (advisor) ; Flachs, Pavel (referee) ; Kutejová, Eva (referee)
Disorders of ATP synthase, the key enzyme of mitochondrial energy provision belong to the most severe metabolic diseases presenting mostly as early-onset mitochondrial encephalo-cardio-myopathies. Mutations in four nuclear genes can result in isolated deficiency of ATP synthase, all sharing a similar biochemical phenotype - pronounced decrease in the content of fully assembled and functional ATP synthase complex. The thesis summarises studies on two distinct causes of ATP synthase deficiency. First is TMEM70 protein, a novel ancillary factor of ATP synthase, which represents most frequent determinant of severe inborn deficiency of ATP synthase. TMEM70 is a 21 kDa protein of the inner mitochondrial membrane, facilitating the biogenesis of mitochondrial ATP synthase, possibly through TMEM70 protein region exposed to the mitochondrial matrix, but the proper regulatory mechanism remains to be elucidated. In TMEM70-lacking patient fibroblasts the low content of ATP synthase induces compensatory adaptive upregulation of mitochondrial respiratory chain complexes III and IV, interestingly by a posttranscriptional mechanisms. The second type of ATP synthase deficiency studied was mtDNA m.9205delTA mutation affecting maturation of MT-ATP8/MT-ATP6/MT-CO3 mRNA and thus biosynthesis of Atp6 (subunit a) and Cox3...
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Structural and Functional Interactions of Mitochondrial ADP-Phosphorylating Apparatus
Nůsková, Hana ; Houštěk, Josef (advisor) ; Kolarov, Jordan (referee) ; Kuda, Ondřej (referee) ; Panicucci Zíková, Alena (referee)
The complexes of the oxidative phosphorylation (OXPHOS) system in the inner mitochondrial membrane are organised into structural and functional super-assemblies, so-called supercomplexes. This type of organisation enables substrate channelling and hence improves the overall OXPHOS efficiency. ATP synthase associates into dimers and higher oligomers. Within the supercomplex of ATP synthasome, it interacts with ADP/ATP translocase (ANT), which exchanges synthesised ATP for cytosolic ADP, and inorganic phosphate carrier (PiC), which imports phosphate into the mitochondrial matrix. The existence of this supercomplex is generally accepted. Experimental evidence is however still lacking. In this thesis, structural interactions between ATP synthase, ANT and PiC were studied in detail. In addition, the interdependence of their expression was examined either under physiological conditions in rat tissues or using model cell lines with ATP synthase deficiencies of different origin. Specifically, they included mutations in the nuclear genes ATP5E and TMEM70 that code for subunit ε and the ancillary factor of ATP synthase biogenesis TMEM70, respectively, and a microdeletion at the interface of genes MT-ATP6 and MT-COX3 that impairs the mitochondrial translation of both subunit a of ATP synthase and subunit Cox3...
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Deletions in human mitochondrial DNA and causes of their formation
Zdobinský, Tomáš ; Tesařová, Markéta (advisor) ; Kazantsev, Dmitry (referee)
Mitochondria are organelles of eukaryotic cells that primarily provide energy metabolism, but also participate in metabolic processes such as biosynthesis of amino acids, heme groups, Fe-S clusters etc. Mitochondrial disorders represent heterogeneous group of diseases which can occur in both child and adult life. They affect various tissues and organs in different ways, most often manifesting themselves as disorders of nervous system, skeletal muscle, liver, kidneys or endocrine system. Mitochondrial DNA deletions contribute to pathogenesis of many of those diseases and they are a symptom of several defined syndromes. They most likely arise as a result of replication stalling resulting in a double strand break of DNA. This can be caused primarily by pathogenic changes in replication apparatus and nucleotide metabolism proteins. The aim of this work is to summarize the knowledge about mitochondria and structure and replication of their genome, but also to create a summary of the most important proteins whose mutation leads to mitochondrial diseases accompanied by deletions in mtDNA and to outline the mechanism by which they arise.
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Use of Canistherapy for Stimulation of Persons with Rare Diseases
Prokopová, Zuzana ; Hájková, Vanda (advisor) ; Šumníková, Pavlína (referee)
The aim of this thesis was to assess the influence of canistherapeutic intervention on the level of fine motor skills in patients with rare diseases, namely mitochondrial encephalocardiomyopathy caused by TMEM70 gene mutation and Leigh syndrome. Canistherapeutic intervention in these patients is based on activation of motoric functions during programme reasonably designed according to the needs of specific patients. The assistance of the dog is used to achieve this activation. The dog acts as an important motivational factor and the direct contact with it contributes to development of sensomotoric skills of these patients. The thesis summarizes general information about rare diseases and focuses on one of the subgroups of mitochondrial disorders. It presents knowledge about the Leigh syndrome and mitochondrial encephalocardiomyopathy caused by TMEM70 gene mutation. Subsequently the thesis presents information about canistherapy and fine motor skills. The thesis further contains case reports of patients, data from research units and their evaluation. The aim of the thesis was to find out whether patients with mitochondrial disease show improvement of quality and effectivity of selected grasp forms and thus faster and more precise execution assigned tasks focusing on object manipulations. Partial...
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