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Importance of glycolysis and oxidative phosphorylation in the metabolism of mesenchymal stem cells
Fráňová, Markéta ; Krulová, Magdaléna (advisor) ; Rohlenová, Kateřina (referee)
Mesenchymal stem cells (MSCs) are classified as multipotent stem cells. They possess the ability to differentiate into many cell types, promote angiogenesis, increase cell survival in damaged tissue and modulate the immune response. These functions of MSCs are used in the treatment of various injuries and some diseases. This work characterizes MSCs, with a focus on their energy metabolism, specifically on the switch in their metabolic phenotype between glycolysis and oxidative phosphorylation in different states of MSCs, during cell culture and after transplantation. Finally, two modulations of MSC metabolism are presented, including cultivation in a hypoxic environment and quiescence induced by serum deprivation, which increase cell survival under the ischemic conditions that MSCs enter after transplantation. Key words: mesenchymal stem cells, metabolism, glycolysis, oxidative phosphorylation
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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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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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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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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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Oxidative phosphorylation system in rare types of mitochondrial diseases
Zdobinský, Tomáš ; Tesařová, Markéta (advisor) ; Pecinová, Alena (referee)
In their bioenergetic metabolism mammalian cells are primarily dependent on ATP production through the oxidative phosphorylation system (OXPHOS). Defects of OXPHOS function can lead to occurrence of mitochondrial disorders with different severity and diverse symptoms. Most severely affected are usually tissues with high energy demand which are also difficult to access for biochemical and other examinations. The aim of this thesis was mainly to characterize the effects of mutations in seven different genes (OPA1, DARS2, NDUFS8, NR2F1, HTRA2, MGME1, POLG) on bioenergetic metabolism and mitochondrial network structure of skin fibroblasts from eight different patients diagnosed with mitochondrial disorders. The main method used was measurement of oxygen uptake by permeabilized cells using highly sensitive polarography. Significant changes in fibroblast respiration of four patients were found. Changes in mitochondrial network morphology were found in two of those and two other patient cell lines compared to controls using fluorescent microscopy and different cultivating conditions. Skin fibroblasts are relatively easy to obtain and offer a number of benefits for both diagnostic and study purposes. The results of this work illustrate the possibilities of their use for validation of potential causal...
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Functional characterization of LACE1 APTase and mitochondrial AAA proteases YME1L and AFG3L2 in mitochondrial protein homeostasis.
Tesařová, Jana ; Stibůrek, Lukáš (advisor) ; Kalous, Martin (referee) ; Pecina, Petr (referee)
Mitochondrial protein homeostasis is crucial for cellular function and integrity. It is ensured by many specific mitochondrial proteases with possible chaperone functions located across the various mitochondrial subcompartments. In the first part, we have focused on characterization of functional overlap and cooperativity of proteolytic subunits AFG3L2 and YME1L of the mitochondrial inner membrane complexes m- and i-AAA in HEK293 cells. The double AFG3L2/YME1L knockdown cells showed severe alteration in OPA1 protein processing, marked elevation in OMA1 protease and severe reduction in SPG7. Our results reveal cooperative and partly redundant involvement of AFG3L2 and YME1L in the maintenance of mitochondrial protein homeostasis and further emphasize their importance for mitochondrial and cellular function and integrity. The aim of the second part was to characterize the cellular function of LACE1 (lactation elevated 1) in mitochondrial protein homeostasis. LACE1 protein is a human homologue of yeast Afg1 (ATPase family gene 1) ATPase. We show that LACE1 is a mitochondrial integral membrane protein that exists as a part of three complexes of approximately 140, 400 and 500 kDa. We demonstrate that LACE1 mediates degradation of nuclear-encoded complex IV subunits COX4, COX5A and COX6A. Using affinity...
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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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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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