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Energy metabolism of skeletal muscle
Elkalaf, Moustafa GamalEldin Mahmoud Mohamed ; Anděl, Michal (advisor) ; Drahota, Zdeněk (referee) ; Žurmanová, Jitka (referee)
Skeletal muscle is the largest tissue in the body and plays a marked role in the homeostasis of the body metabolic state. Mitochondria have been proven to contribute to the pathophysiology of various metabolic diseases, either due to defects in their bioenergetic properties or the production of reactive oxygen species. In this work murine myoblasts C2C12 were used as a model of skeletal muscle in vitro, and rat muscle was used to prepare homogenate enriched in the mitochondrial fraction. This work investigates the changes in respiratory parameters in models where mitochondrial oxidative phosphorylation is induced by changing the available consumable substrates in the culture media, such as replacing glucose by galactose, and the effect of treating the cells with high glucose concentration during the process of differentiation on mitochondrial performance. It also investigates the changes in bioenergetic profiles in samples treated with inactive derivatives of the widely used triphenylphosphonium (TPP+) salts to target mitochondria by various probes and antioxidants. The methods used in this study included evaluating mitochondrial parameters in intact and permeabilized cells by real time measurement of the oxygen consumption rate using the extracellular flux analyzer, measuring the enzymatic...
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Effect of selected nutrients on skeletal muscle mitochondrial metabolism
Tůmová, Jana ; Anděl, Michal (advisor) ; Poledne, Rudolf (referee) ; Drahota, Zdeněk (referee)
Skeletal muscle plays an important role in the maintenance of whole-body metabolic homeostasis. Metabolic alterations of skeletal muscle contribute to the pathogenesis of a wide range of human diseases, such as obesity, type 2 diabetes and hypertension. Relative excess and suboptimal composition of nutrients negatively affect skeletal muscle metabolism and a better understanding of mechanisms involved in these changes is of central importance. The aim of the work presented in this thesis was to explore cell viability and mitochondrial respiratory parameters following experimentally induced changes in the availability or composition of selected nutrients (fatty acids and glutamine). We attempted to elucidate the mechanisms responsible for the observed changes, such as mitochondrial DNA (mtDNA) damage, or nuclear receptors activation. The studies were performed in vitro on skeletal muscle cell culture models. In addition, we examined mitochondrial function and fat accumulation in skeletal muscle of vegans, i.e. subjects consuming a strict plant-based diet. Using C2C12 skeletal muscle cells we studied the effects of free fatty acids (FFA). We found that relatively low doses of saturated palmitic acid increased hydrogen peroxide production and induced mtDNA damage, mitochondrial respiratory dysfunction...
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Developmental, pathobiochemical and molecular aspects of selected inborn errors of metabolism
Kolářová, Hana ; Honzík, Tomáš (advisor) ; Drahota, Zdeněk (referee) ; Morava Kozicz, Eva (referee)
Inborn errors of metabolism represent a heterogenous group of rare conditions, most having an incidence of less than 1 in 100,000 births. Because of their low prevalence, they are on the margin of attention of general research and even more so of large pharmaceutical companies. Study of rare diseases is the only way to design therapeutic options in order to improve quality of life of affected patients. Present Thesis particularly focuses on disturbances in mitochondrial energy metabolism. The main goals were the characterization of mitochondrial biogenesis within foetal development, as well as in childhood and adulthood. Another aim was to define clinical, biochemical and molecular aspects of mitochondrial optic neuropathies in childhood and adulthood. This work supported the earlier observations that gestational week 22 is the edge of viability, which has to be taken into account in upcoming discussions about guidelines on resuscitation of preterm neonates. Secondly, over last four years, we managed to examine and describe large cohort of patients with optic neuropathies based on a mitochondrial dysfunction. We have managed to characterize the biochemical and molecular-genetic background in more than 200 patients, and both selected cases (LHON/MELAS overlap syndrome) and cohort studies (MELAS,...
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Modulation of body fat content by targeting the lipid metabolism of adipose tissue
Šponarová, Jana ; Kopecký, Jan (advisor) ; Konvalinka, Jan (referee) ; Drahota, Zdeněk (referee)
CONCLUSIONS 1. Induction of obesiý resistance in mice by transgenic expression of UCP1 in white fat can be explained by a metabolic switch ínadipocýes, due to depressíon oť celluiar energy charge, in situ activaÍion of AMPK, down- regulation ofadipogenic genes and increase in lipid oxidation. 2. AMPK cascade is involved in the fat depot-specific metabolic responses in various fat depots to starvation. Activation of the cascade occurred in epididymal but not in subcutaneous fat in mice. The activation of AMPK in adipocytes might represent an important mechanism by which body fat stores are regulated and may contributes to regional differences in the metabolic properties ofadipose tissue depots. Dietary EPA and DHA reduce development of obesity induced in mice by high fat diets, in part due to counteracting increase in tissue cellularity, particularly in epididymal íat.Low EPA/DHA ratio potentiates the anti- adipogenic efíect. Dietary EPA and DHA induce a metabolic shift in white adipose tissue by up-regulating genes for mitochondrial proteins, including their regulatory genes PGCIa and NRF-I, and increase B-oxidation while depressing lipogenesis, preferentially in the epididymal fat in the abdomen. 3. 4. J. 21
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Energy Metabolism in Obesity: Metabolic Flexibility and Dietary Fat
Bardová, Kristina ; Kopecký, Jan (advisor) ; Drahota, Zdeněk (referee) ; Žurmanová, Jitka (referee)
Abstract Adipose tissue is an important homeostatic tissue within the body. It not only buffers FA availability in the organism, but also releases important autocrine, paracrine or endocrine factors influencing energy metabolism. The biology of adipose tissue is closely related and underlies whole-body metabolic consequences of obesity, such as type II. diabetes. Obesity and type II. diabetes causes and maybe are caused by metabolic inflexibility, the inability of organism to adapt fuel oxidation to fuel availability. The intersection of adipose tissue biology, obesity and its metabolic consequences and theory of metabolic flexibility is discussed in this PhD. thesis. Five articles dealing with above mentioned topics are included. The general goal of this study was to compare several approaches for metabolic flexibility assessment with respect to overall energy homeostasis. The specific goals, delineated by included articles, were (i) to evaluate the influence of n-3 long chain fatty acids (n-3 LC-PUFA), rosiglitazone, and their combination, on metabolic flexibility at a whole-body and cellular level; (ii) to evaluate impact of high-fat feeding on metabolic flexibility of male and female mice; (iii) to evaluate the impact of chenodeoxycholic acid (CDCA)...
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Effect of selected nutrients on skeletal muscle mitochondrial metabolism
Tůmová, Jana ; Anděl, Michal (advisor) ; Poledne, Rudolf (referee) ; Drahota, Zdeněk (referee)
Skeletal muscle plays an important role in the maintenance of whole-body metabolic homeostasis. Metabolic alterations of skeletal muscle contribute to the pathogenesis of a wide range of human diseases, such as obesity, type 2 diabetes and hypertension. Relative excess and suboptimal composition of nutrients negatively affect skeletal muscle metabolism and a better understanding of mechanisms involved in these changes is of central importance. The aim of the work presented in this thesis was to explore cell viability and mitochondrial respiratory parameters following experimentally induced changes in the availability or composition of selected nutrients (fatty acids and glutamine). We attempted to elucidate the mechanisms responsible for the observed changes, such as mitochondrial DNA (mtDNA) damage, or nuclear receptors activation. The studies were performed in vitro on skeletal muscle cell culture models. In addition, we examined mitochondrial function and fat accumulation in skeletal muscle of vegans, i.e. subjects consuming a strict plant-based diet. Using C2C12 skeletal muscle cells we studied the effects of free fatty acids (FFA). We found that relatively low doses of saturated palmitic acid increased hydrogen peroxide production and induced mtDNA damage, mitochondrial respiratory dysfunction...
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Energy metabolism of skeletal muscle
Elkalaf, Moustafa GamalEldin Mahmoud Mohamed ; Anděl, Michal (advisor) ; Drahota, Zdeněk (referee) ; Žurmanová, Jitka (referee)
Skeletal muscle is the largest tissue in the body and plays a marked role in the homeostasis of the body metabolic state. Mitochondria have been proven to contribute to the pathophysiology of various metabolic diseases, either due to defects in their bioenergetic properties or the production of reactive oxygen species. In this work murine myoblasts C2C12 were used as a model of skeletal muscle in vitro, and rat muscle was used to prepare homogenate enriched in the mitochondrial fraction. This work investigates the changes in respiratory parameters in models where mitochondrial oxidative phosphorylation is induced by changing the available consumable substrates in the culture media, such as replacing glucose by galactose, and the effect of treating the cells with high glucose concentration during the process of differentiation on mitochondrial performance. It also investigates the changes in bioenergetic profiles in samples treated with inactive derivatives of the widely used triphenylphosphonium (TPP+) salts to target mitochondria by various probes and antioxidants. The methods used in this study included evaluating mitochondrial parameters in intact and permeabilized cells by real time measurement of the oxygen consumption rate using the extracellular flux analyzer, measuring the enzymatic...
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The role of mitochondrial creatine kinase and hexokinase in cardioprotective mechanisms induced by chronic hypoxia
Wasková, Petra ; Žurmanová, Jitka (advisor) ; Drahota, Zdeněk (referee) ; Nováková, Olga (referee)
IN ENGLISH The ischemia-reperfusion (I/R) injury, which is a consequence of myocardial infarction, represents a major cause of death worldwide. One of the most effective cardioprotective interventions increasing the resistance of hearts to the I/R injury is the adaptation to a chronic hypoxia (CH). However, the molecular mechanisms of CH are still not well understood. The most important factors responsible for the I/R injury are reactive oxygen species (ROS) produced by complexes I and III within the mitochondrial electron transport chain. Potential candidates maintaining ROS at a low level are mitochondrial creatine kinase (mtCK) and two hexokinase isoforms (HK1 and HK2). These enzymes highly support the mitochondrial oxidative phosphorylation by increasing the availability of ADP for complex V of the respiratory chain. In addition, the HK binding to mitochondria inhibits binding of the pro- apoptotic protein BAX, thereby protecting cardiac cells against apoptosis. Besides the mitochondrial CK isoform, there are two cytosolic CK (CKM and CKB) present in cardiomyocytes that help to maintain energy homeostasis. Based on the known anatomical and physiological differences between the left (LV) and the right (RV) ventricles, the first study focused on the comparing ventricles in terms of the energy...
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