This study presents an in-depth analysis of mitochondrial enzyme activities in Friedreich's ataxia (FA) patients, focusing on the Electron Transport Chain complexes I, II, and IV, the Krebs Cycle enzyme Citrate Synthase, and Coenzyme Q10 levels. It examines a cohort of 34 FA patients, comparing their mitochondrial enzyme activities and clinical parameters, including disease duration and cardiac markers, with those of 17 healthy controls. The findings reveal marked reductions in complexes II and, specifically, IV, highlighting mitochondrial impairment in FA. Additionally, elevated Neurofilament Light Chain levels and cardiomarkers were observed in FA patients. This research enhances our understanding of FA pathophysiology and suggests potential biomarkers for monitoring disease progression. The study underscores the need for further clinical trials to validate these findings, emphasizing the critical role of mitochondrial dysfunction in FA assessment and treatment.

• MeSH
• biologické markery * metabolismus   MeSH
• citrátsynthasa metabolismus   MeSH
• dospělí MeSH
• Friedreichova ataxie * diagnóza   MeSH
• kohortové studie MeSH
• lidé středního věku MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• ubichinon * analogy a deriváty   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Psychosis is a state of altered thoughts which often accompanies schizophrenia. It was suggested that changes in energetic metabolism accompany psychosis and post-psychosis states. Here, we use the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 to experimentally induce psychosis-like behavior in rats. We addressed an effect of single and repeated (5×) MK-801 application (0.3 mg/kg; i.p.) on the energy metabolism in homogenates and crude mitochondrial fraction (CMF) of the striatum (STR), prefrontal cortex (PFC), and the hippocampus (HIP) of the adult male Wistar rat (n = 39). In each brain region, we assessed activity of glycolytic (hexokinase (HK) and lactate dehydrogenase (LDH)) and Krebs cycle enzymes (citrate synthase (CS) and malate dehydrogenase (MDH)) 2 h and 3 days (3d) after the last MK-801 application together with relative respiratory rates assessment in tissue homogenate. In STR, a single MK-801 application led to a decrease in the LDH (p = 0.0035) and the increase of the MDH (p = 0.0043) activities following 3d. Therein, repeated MK-801 doses evoked increased LDH (p = 0.0204) and CS (p = 0.0019) activities in the homogenate 2 h and increased HK (p = 0.0007) 3d after the last application. Elevated HK activity within CMF was observed after 3d (p = 0.0054). In PFC, repeated MK-801 application decreased HK activity in the homogenate 3d after the final application (p = 0.0234). Correspondingly, PFC HK activity in CMF of repeated administration samples dropped (p = 0.003). In HIP, repeated MK-801 administration led to increased respiration of SDH (p = 0.0475) only 2 h after the last application and decreased CS activity (p = 0.0160) was observed 3d after the last application. Our results indicate a progressive metabolic dysregulation of glycolytic and Krebs cycle enzymes following repeated inhibition of NMDA receptors activity in a region-specific manner. Energetic alterations may form a basis for persisting cognitive problems during and following a psychosis in schizophrenia patients.

• MeSH
• citrátový cyklus MeSH
• citrátsynthasa metabolismus   farmakologie   MeSH
• dizocilpinmaleát * farmakologie   MeSH
• hexokinasa metabolismus   farmakologie   MeSH
• hipokampus MeSH
• krysa rodu rattus MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• lidé MeSH
• N-methylaspartát * farmakologie   MeSH
• potkani Wistar MeSH
• prefrontální mozková kůra MeSH
• receptory N-methyl-D-aspartátu metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mitochondrial retrograde signaling is a mitochondria-to-nucleus communication pathway, conserved from yeast to humans, by which dysfunctional mitochondria relay signals that lead to cell stress adaptation in physiopathological conditions via changes in nuclear gene expression. The most comprehensive picture of components and regulation of retrograde signaling has been obtained in Saccharomyces cerevisiae, where retrograde-target gene expression is regulated by RTG genes. In this chapter, we describe methods to measure mitochondrial retrograde pathway activation at the level of mRNA and protein products in yeast model systems, including cell suspensions and microcolonies. In particular, we will focus on three major procedures: mRNA levels of RTG-target genes, such as those encoding for peroxisomal citrate synthase (CIT2), aconitase, and NAD+-specific isocitrate dehydrogenase subunit 1 by real-time PCR; expression analysis of CIT2-gene protein product (Cit2p-GFP) by Western blot and fluorescence microscopy; the phosphorylation status of transcriptional factor Rtg1/3p which controls RTG-target gene transcription.

• MeSH
• akonitáthydratasa genetika   metabolismus   MeSH
• buněčné jádro genetika   metabolismus   MeSH
• citrátsynthasa genetika   metabolismus   MeSH
• fosforylace MeSH
• intracelulární signální peptidy a proteiny metabolismus   MeSH
• isocitrátdehydrogenasa genetika   metabolismus   MeSH
• mitochondrie metabolismus   patologie   MeSH
• Saccharomyces cerevisiae - proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• signální transdukce MeSH
• transkripční faktory BHLH-Zip metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Impaired myocardial bioenergetics is a hallmark of many cardiac diseases. There is a need of a simple and reproducible method of assessment of mitochondrial function from small human myocardial tissue samples. In this study we adopted high-resolution respirometry to homogenates of fresh human cardiac muscle and compare it with isolated mitochondria. We used atria resected during cardiac surgery (n = 18) and atria and left ventricles from brain-dead organ donors (n = 12). The protocol we developed consisting of two-step homogenization and exposure of 2.5% homogenate in a respirometer to sequential addition of 2.5 mM malate, 15 mM glutamate, 2.5 mM ADP, 10 μM cytochrome c, 10 mM succinate, 2.5 μM oligomycin, 1.5 μM FCCP, 3.5 μM rotenone, 4 μM antimycin and 1 mM KCN or 100 mM Sodium Azide. We found a linear dependency of oxygen consumption on oxygen concentration. This technique requires < 20 mg of myocardium and the preparation of the sample takes <20 min. Mitochondria in the homogenate, as compared to subsarcolemmal and interfibrillar isolated mitochondria, have comparable or better preserved integrity of outer mitochondrial membrane (increase of respiration after addition of cytochrome c is up to 11.7±1.8% vs. 15.7±3.1%, p˂0.05 and 11.7±3.5%, p = 0.99, resp.) and better efficiency of oxidative phosphorylation (Respiratory Control Ratio = 3.65±0.5 vs. 3.04±0.27, p˂0.01 and 2.65±0.17, p˂0.0001, resp.). Results are reproducible with coefficient of variation between two duplicate measurements ≤8% for all indices. We found that whereas atrial myocardium contains less mitochondria than the ventricle, atrial bioenergetic profiles are comparable to left ventricle. In conclusion, high resolution respirometry has been adapted to homogenates of human cardiac muscle and shown to be reliable and reproducible.

• MeSH
• citrátsynthasa metabolismus   MeSH
• dospělí MeSH
• energetický metabolismus MeSH
• kryoprezervace MeSH
• kyslík metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mastné kyseliny metabolismus   MeSH
• mitochondriální membrány metabolismus   MeSH
• oxidace-redukce MeSH
• senioři MeSH
• srdeční mitochondrie metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: The bipolar affective disorder (BAD) pathophysiology is multifactorial and has not been fully clarified. METHOD: We measured selected mitochondrial parameters in peripheral blood components. The analyses were performed for patients suffering from a manic episode during remission and were compared to those performed for healthy controls. BAD was clinically evaluated using well-established diagnostic scales and questionnaires. Mitochondrial respiration was examined in intact and permeabilized blood platelets using high-resolution respirometry. The citrate synthase (CS) and electron transport system (ETS) complex (complex I, II, and IV) activities were examined in platelets. RESULTS: The CS, complex II and complex IV activities were decreased in the BAD patients, complex I activity was increased, and the ratio of complex I to CS was significantly increased. In the intact platelets, respiration after complex I inhibition and residual oxygen consumption were decreased in the BAD patients compared to the healthy controls. In the permeabilized platelets, a decreased ETS capacity was found in the BAD patients. No significant differences were found between BAD patients in mania and remission. CONCLUSION: Increased complex I activity can be a compensatory mechanism for decreased CS and complex II and IV activities. We conclude that complex I and its abnormal activity contribute to defects in cellular energy metabolism during a manic episode and that the deficiency in the complex's functioning, but not the availability of oxidative phosphorylation substrates, seems to be responsible for the decreased ETS capacity in BAD patients. The observed parameters can be further evaluated as 'trait' markers of BAD.

• MeSH
• bipolární porucha komplikace   farmakoterapie   metabolismus   MeSH
• citrátsynthasa metabolismus   MeSH
• dospělí MeSH
• elektronový transportní řetězec metabolismus   MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• trombocytopatie komplikace   metabolismus   MeSH
• trombocyty metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Methyltriphenylphosphonium (TPMP) salts have been widely used to measure the mitochondrial membrane potential and the triphenylphosphonium (TPP+) moiety has been attached to many bioactive compounds including antioxidants to target them into mitochondria thanks to their high affinity to accumulate in the mitochondrial matrix. The adverse effects of these compounds on cellular metabolism have been insufficiently studied and are still poorly understood. Micromolar concentrations of TPMP cause a progressive inhibition of cellular respiration in adherent cells without a marked effect on mitochondrial coupling. In permeabilized cells the inhibition was limited to NADH-linked respiration. We found a mixed inhibition of the Krebs cycle enzyme 2-oxoglutarate dehydrogenase complex (OGDHC) with an estimated IC50 3.93 [3.70-4.17] mM, which is pharmacologically plausible since it corresponds to micromolar extracellular concentrations. Increasing the lipophilic character of the used TPP+ compound further potentiates the inhibition of OGDHC activity. This effect of TPMP on the Krebs cycle ought to be taken into account when interpreting observations on cells and mitochondria in the presence of TPP+ derivatives. Compounds based on or similar to TPP+ derivatives may also be used to alter OGDHC activity for experimental or therapeutic purposes.

• MeSH
• buněčné linie MeSH
• citrátový cyklus účinky léků   MeSH
• citrátsynthasa účinky léků   metabolismus   MeSH
• glutamátdehydrogenasa účinky léků   metabolismus   MeSH
• isocitrátdehydrogenasa účinky léků   metabolismus   MeSH
• ketoglutarátdehydrogenasový komplex antagonisté a inhibitory   metabolismus   MeSH
• kosterní svaly enzymologie   MeSH
• krysa rodu rattus MeSH
• malátdehydrogenasa účinky léků   metabolismus   MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• oniové sloučeniny farmakologie   MeSH
• potkani Wistar MeSH
• pyruvátdehydrogenasový komplex účinky léků   metabolismus   MeSH
• svalové mitochondrie účinky léků   enzymologie   MeSH
• tritylové sloučeniny farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Mitochondrial dysfunctions significantly contribute to the pathogenesis of Alzheimer's disease (AD). Here, we studied the relationship between AD and changes in the mitochondrial rates of respiration in blood platelets, respiratory chain complexes activity, and coenzyme Q10 plasma concentrations. In intact platelets obtained from AD patients, we observed a decrease in endogenous basal respiration rates, a decrease in the maximal capacity of the electron transport system (ETS), and higher respiratory rates after inhibiting complex I of the ETS. When normalized for citrate synthase activity, rotenone inhibited respiratory rates and complex I activity was significantly altered. In permeabilized platelets, mitochondrial respiration was completely rescued by the addition of complex I substrates. The changes in mitochondrial respiratory parameters were not associated with the progression of AD except for the capacity of the ETS in permeabilized platelets. In AD, complex I activity was increased, complex IV activity was decreased, and coenzyme Q10 plasma concentrations were decreased. Our data indicate that both insufficiency in substrates entering into the oxidative phosphorylation system and functional disturbances in the ETS complex are responsible for the decrease in respiration observed in intact platelets in AD patients. Analyses of complex IV activity, the respiratory rates of intact platelets, and the capacity of the ETS in permeabilized platelets may enable the characterization of mitochondrial dysfunctions in the initial stage of AD.

• MeSH
• Alzheimerova nemoc genetika   metabolismus   MeSH
• apolipoproteiny E genetika   MeSH
• biologické markery metabolismus   MeSH
• citrátsynthasa metabolismus   MeSH
• frekvence genu MeSH
• lidé středního věku MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• polymorfismus genetický MeSH
• respirační komplex I metabolismus   MeSH
• respirační komplex IV metabolismus   MeSH
• ROC křivka MeSH
• senioři MeSH
• trombocyty metabolismus   MeSH
• ubichinon analogy a deriváty   krev   MeSH
• záznam o duševním stavu MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Oxidative phosphorylation is a key process of intracellular energy transfer by which mitochondria produce ATP. Isolated mitochondria serve as a biological model for understanding the mitochondrial respiration control, effects of various biologically active substances, and pathophysiology of mitochondrial diseases. The aim of our study was to evaluate pig brain mitochondria as a proper biological model for investigation of activity of the mitochondrial electron transport chain. Oxygen consumption rates of isolated pig brain mitochondria were measured using high-resolution respirometry. Mitochondrial respiration of crude mitochondrial fraction, mitochondria purified in sucrose gradient, and mitochondria purified in Percoll gradient were assayed as a function of storage time. Oxygen flux and various mitochondrial respiratory control ratios were not changed within two days of mitochondria storage on ice. Leak respiration was found higher and Complex I-linked respiration lower in purified mitochondria compared to the crude mitochondrial fraction. Damage to both outer and inner mitochondrial membrane caused by the isolation procedure was the greatest after purification in a sucrose gradient. We confirmed that pig brain mitochondria can serve as a biological model for investigation of mitochondrial respiration. The advantage of this biological model is the stability of respiratory parameters for more than 48 h and the possibility to isolate large amounts of mitochondria from specific brain areas without the need to kill laboratory animals. We suggest the use of high-resolution respirometry of pig brain mitochondria for research of the neuroprotective effects and/or mitochondrial toxicity of new medical drugs.

• MeSH
• biologické modely * MeSH
• buněčné dýchání MeSH
• citrátsynthasa metabolismus   MeSH
• kyslík metabolismus   MeSH
• mitochondriální membrány metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• mozek metabolismus   MeSH
• Sus scrofa MeSH
• transport elektronů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We report that tumor cells without mitochondrial DNA (mtDNA) show delayed tumor growth, and that tumor formation is associated with acquisition of mtDNA from host cells. This leads to partial recovery of mitochondrial function in cells derived from primary tumors grown from cells without mtDNA and a shorter lag in tumor growth. Cell lines from circulating tumor cells showed further recovery of mitochondrial respiration and an intermediate lag to tumor growth, while cells from lung metastases exhibited full restoration of respiratory function and no lag in tumor growth. Stepwise assembly of mitochondrial respiratory (super)complexes was correlated with acquisition of respiratory function. Our findings indicate horizontal transfer of mtDNA from host cells in the tumor microenvironment to tumor cells with compromised respiratory function to re-establish respiration and tumor-initiating efficacy. These results suggest pathophysiological processes for overcoming mtDNA damage and support the notion of high plasticity of malignant cells.

• MeSH
• citrátsynthasa metabolismus   MeSH
• elektronový transportní řetězec metabolismus   MeSH
• energetický metabolismus MeSH
• homologní transplantace MeSH
• melanom experimentální patologie   MeSH
• messenger RNA metabolismus   MeSH
• mitochondriální DNA metabolismus   MeSH
• mitochondrie genetika   metabolismus   ultrastruktura   MeSH
• myši inbrední BALB C MeSH
• myši inbrední C57BL MeSH
• myši inbrední NOD MeSH
• myši SCID MeSH
• myši MeSH
• NADH-dehydrogenasa genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádory plic patologie   sekundární   MeSH
• proliferace buněk MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The aim of this study was to investigate changes in the activity of individual mitochondrial respiratory chain complexes (I, II/III, IV) and citrate synthase induced by pharmacologically different cannabinoids. In vitro effects of selected cannabinoids on mitochondrial enzymes were measured in crude mitochondrial fraction isolated from pig brain. Both cannabinoid receptor agonists, Δ(9)-tetrahydrocannabinol, anandamide, and R-(+)-WIN55,212-2, and antagonist/inverse agonists of cannabinoid receptors, AM251, and cannabidiol were examined in pig brain mitochondria. Different effects of these cannabinoids on mitochondrial respiratory chain complexes and citrate synthase were found. Citrate synthase activity was decreased only by Δ(9)-tetrahydrocannabinol and AM251. Significant increase in the complex I activity was induced by anandamide. At micromolar concentration, all the tested cannabinoids inhibited the activity of electron transport chain complexes II/III and IV. Stimulatory effect of anandamide on activity of complex I may participate on distinct physiological effects of endocannabinoids compared to phytocannabinoids or synthetic cannabinoids. Common inhibitory effect of cannabinoids on activity of complex II/III and IV confirmed a non-receptor-mediated mechanism of cannabinoid action on individual components of system of oxidative phosphorylation.

• MeSH
• antagonisté kanabinoidních receptorů farmakologie   MeSH
• citrátsynthasa metabolismus   MeSH
• kanabinoidy farmakologie   MeSH
• mitochondrie účinky léků   metabolismus   MeSH
• mozek účinky léků   metabolismus   MeSH
• prasata MeSH
• respirační komplex I metabolismus   MeSH
• respirační komplex II metabolismus   MeSH
• respirační komplex III metabolismus   MeSH
• respirační komplex IV metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH