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Oxidative phosphorylation addiciton as a new approach to the therapy of neoplastic diseases
Růžičková, Anna ; Neužil, Jiří (advisor) ; Merta, Ladislav (referee)
Neoplastic diseases belong at present time among the most frequent causes of premature death in industrialized countries. Discovery of novel approaches to their therapy is highly warranted. Recent results point to the requirement of mitochondrial respiration for tumor progression. This is linked primarily to recent discovery of horizontal transfer of mitochondrial transfer from the host to cancer cells with damaged mitochondrial DNA. This is a needed for the recovery of mitochondrial respiration, a prerequisite for tumor progression. It has appeared that the rate of respiration necessary for tumor progression differs in individual types of tumors. This hypothesis, which is refer to as 'oxidative phosphorylation addiction', however, needs to be verified. It could serve as the basis for proposing of novel therapic strategy for neoplastic diseases, using compounds that directly affect mitochondrial respiratory complexes. Key words: mitochondria, oxidative phosphorylation, horizontal transfer of mitochondrial DNA, neoplastic pathologies, mitochondrially targeted anti-cancer agents
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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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Study of leukemic cells' metabolism in association with response to the therapy
Šimčíková, Markéta ; Starková, Júlia (advisor) ; Čuřík, Nikola (referee)
Acute lymphoblastic leukemia (ALL) is the most common malignant dise- ase in children. Despite great advancements in treatment of this disease, around 15-20 % of patients suffer a relapse. One of the possible reasons for relapse is developed resistance to cytostatic drugs. L-asparaginase is an im- portant chemotherapy component for childhood ALL and resistance to this drug often complicates treatment. To date, causes of developing resistance have not been sufficiently described. This thesis is a part of a greater research project focusing on mechanisms of L-asparaginase's activity and reasons for developing resistance to this chemotherapeutic agent. Differential metabolic requirements of cancerous cells have been described as early as 1924 by O. H. Warburg and they have been subject to scientific inquiry since. This study aimed to describe the relationship between basal metabolic determinants of leukemia cells and their sensitivity to L-asparaginase. For this reason, two metabolic pathways, glycolysis and oxidative phosphorylati- on, were studied in detail using a Seahorse Bioanalyzer. Further, expression of specific genes involved in glycolysis was detected. Content of mitochon- drial reticulum in cells, expression of the asparagine synthetase gene, and cell size were also studied. Experiments were...
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Effects of antidepressants and depressive disorders on mitochondrial functions
Hroudová, Jana ; Fišar, Zdeněk (advisor)
Mood disorders are serious diseases. Nevertheless, their pathophysiology is not sufficiently clarified. Biological markers that would facilitate the diagnosis or successful prediction of pharmacotherapy are still being sought. The aim of the study was to find out whether mitochondrial functions are affected by antidepressants, mood stabilizers and depression. Our research is based on recent hypotheses of mood disorders, the advanced monoamine hypothesis, the neurotrophic hypothesis, and the mitochondrial dysfunction hypothesis. We assume that impaired function of mitochondria leads to neuronal damage and can be related to the origin of mood disorders. Effects of antidepressants and mood stabilizers on mitochondrial functions can be related to their therapeutic or side effects. In vitro effects of pharmacologically different antidepressants and mood stabilizers on the activities of mitochondrial enzymes were measured in mitochondria isolated from pig brains (in vitro model). Activity of monoamine oxidase (MAO) isoforms was determined radiochemically, activities of other mitochondrial enzymes were measured spectrophotometrically. Overall activity of the system of oxidative phosphorylation was measured electrochemically using high- resolution respirometry. Methods were modified to measure the same...
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Impact of isolate deficiency of F1FO-ATP syntthase on other complexes of oxidative phosphorylation in skin fibroblasts depending on cullture conditions
Kedrová, Kateřina ; Stiborová, Marie (advisor) ; Poljaková, Jitka (referee)
Isolated deficiency of F1FO-ATPsynthase is a soubgroup of mitochondrial diseases caused by mutations in nuclear and mitochondrial-encoded structural subunits, or nuclear-encoded assembly factors of F1FO-ATPsynthase. The most often mutations are found in a MTATP6 gene localized in the mitochondrial DNA and a TMEM70 gene, localized in the nuclear DNA. A MTATP6 gene encodes subunit a of F1FO-ATPsynthase and its mutation usually leads to reduced phosphorylation activity of F1FO-ATPsynthase. A TMEM70 gene encodes a 21 kDa mitochondrial protein of the inner mitochondrial membrane of not completely explained function and its mutation results in the decrease in a content of fully assembled F1FO- ATPsynthase. The aim of this thesis was to investigate the impact of isolated F1FO- ATPsynthase deficiency on the oxidative phosphorylation system (complex I-IV), other selected mitochondrial proteins, and mitochondrial network in two cell lines of primary human skin fibroblasts with an isolated deficiency of F1FO-ATPsynthase (mutation m.8851T>C in MTATP6 and mutation c.317-2A>G in TMEM70) during the first days of their cultivation in media containing galactose or glucose as a carbohydrate source with a presence or absence of L-glutamine. The control cell line was found to have higher amounts of respiratory chain...
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Expression of selected defects of oxidative phosphorylation system in cultivated fibroblasts
Marková, Michaela ; Hansíková, Hana (advisor) ; Kalous, Martin (referee)
AAbbssttrraacctt:: The mammalian organism is entirely dependent on ATP production by oxidative phosphorylation system (OXPHOS) on the inner mitochondrial membrane. OXPHOS is composed of respiratory chain complexes I-IV, ATP synthase and also include two electron transporters cytochrome c and coenzyme Q. Disorders of mitochondrial energy metabolism caused by OXPHOS defects are characterized by extreme heterogeneity of clinical symptoms, variability of tissues affected and the severity of the defect at the level of individual tissues. The mitochondrial disorders are not always clearly expressed at the level of available tissue or most easily available cultured fibroblasts and/or currently available methods are not capable to detect the defects on the fibroblasts level. The aim of this master thesis was to identify by biochemical methods, especially by high sensitive polarography, OXPHOS disorders in cultured fibroblasts. Cell lines from 10 patients with isolated (SURF21, SCO1 ND1, ND5) or combined defects of OXPHOS complexes whose biochemical defect was confirmed in muscle tissue as well as 14 patients with non- mitochondrial diseases (8 patients with Huntington disease, 6 patients with disorder of sulphur amino acids metabolism) were analysed. Furthermore impact of various cultivation conditions on OXPHOS...
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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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The role of mitochondria in adaptation to chronic hypoxia in the spontaneously hypertensive and conplastic rats.
Weissová, Romana ; Kalous, Martin (advisor) ; Rauchová, Hana (referee)
Adaptation to chronic hypoxia provides cardioprotective effects. Molecular mechanism of this phenomenon is not yet completely understood, but it is known that cardiac mitochondria play an essential role in induction of protective effects. The purpose of this diploma thesis is to study effects of continuous normobaric hypoxia (CNH; 10 % O2, 21 days) on spontaneously hypertensive rats (SHR) and conplastic strain that is derived from SHR. These animals have nuclear genome of SHR strain and mitochondrial genome of Brown Norway (BN) strain. Cardiac homogenate was used to measure enzymatic activity of malate dehydrogenase (MDH), citrate synthase (CS), NADH-cytochrome c oxidoreductase, succinate-cytochrome c oxidoreductase and cytochrome oxidase (COX). Using Western blot procedure the protein amount of antioxidant enzymes was measured - manganese superoxide dismutase and copper-zinc superoxide dismutase (MnSOD, Cu/ZnSOD), catalase and chosen subunits of oxidative phosphorylation complexes (Ndufa9, Sdha, Uqcrc2, COX-4, MTCO1, Atp5a1). Under normoxic conditions the conplastic strain has lower amount of complex IV subunit MTCO1 in comparison with SHR. This subunit is encoded by mitochondrial DNA and it is one of the seven protein-coding genes in conplastic strain that differ from SHR. Adaptation to hypoxia causes an...
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Effects of antidepressants and depressive disorders on mitochondrial functions
Hroudová, Jana ; Fišar, Zdeněk (advisor) ; Martásek, Pavel (referee) ; Kuča, Kamil (referee)
Mood disorders are serious diseases. Nevertheless, their pathophysiology is not sufficiently clarified. Biological markers that would facilitate the diagnosis or successful prediction of pharmacotherapy are still being sought. The aim of the study was to find out whether mitochondrial functions are affected by antidepressants, mood stabilizers and depression. Our research is based on recent hypotheses of mood disorders, the advanced monoamine hypothesis, the neurotrophic hypothesis, and the mitochondrial dysfunction hypothesis. We assume that impaired function of mitochondria leads to neuronal damage and can be related to the origin of mood disorders. Effects of antidepressants and mood stabilizers on mitochondrial functions can be related to their therapeutic or side effects. In vitro effects of pharmacologically different antidepressants and mood stabilizers on the activities of mitochondrial enzymes were measured in mitochondria isolated from pig brains (in vitro model). Activity of monoamine oxidase (MAO) isoforms was determined radiochemically, activities of other mitochondrial enzymes were measured spectrophotometrically. Overall activity of the system of oxidative phosphorylation was measured electrochemically using high- resolution respirometry. Methods were modified to measure the same...
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FoF1-ATP synthase/ATPase in the parasitic protist, \kur{Trypanosoma brucei}
ŠUBRTOVÁ, Karolína
This thesis primarily focuses on the FoF1-ATP synthase/ATPase complex in the parasitic protist, Trypanosoma brucei. Instead of its normal aerobic function to synthesize ATP, it is required to hydrolyze ATP to maintain the m in the infective bloodstream stage of T. brucei and the related parasite, T. b. evansi. To better understand the composition, structure and function of this druggable target, my work focused on deciphering the function of three of the unique Euglenozoa specific subunits that comprise this complex molecular machine. Furthermore, the ADP/ATP carrier, which provides substrates for the FoF1-ATP synthase/ATPase, was functionally characterized and evaluated if it is physically associated with the complexes of the oxidative phosphorylation pathway.
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