complex IV
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Mitochondria are key to cellular energetics, metabolism, and signaling. Their dysfunction is linked to devastating diseases, including mitochondrial disorders, diabetes, neurodegenerative diseases, cardiac disorders, and cancer. Here, we present a knockout mouse model lacking the complex IV assembly factor SMIM20/MITRAC7. SMIM20-/- mice display cardiac pathology with reduced heart weight and cardiac output. Heart mitochondria present with reduced levels of complex IV associated with increased complex I activity, have altered fatty acid oxidation, and display elevated levels of ROS production. Interestingly, mutant mouse ventricular myocytes show unphysiological Ca2+ handling, which can be attributed to the increase in mitochondrial ROS production. Our study presents an example of a tissue-specific phenotype in the context of OXPHOS dysfunction. Moreover, our data suggest a link between complex IV dysfunction and Ca2+ handling at the endoplasmic reticulum through ROS signaling.
- MeSH
- endoplazmatické retikulum metabolismus MeSH
- kardiomyocyty metabolismus MeSH
- membránové proteiny * metabolismus genetika MeSH
- mitochondriální proteiny * metabolismus genetika MeSH
- myokard * metabolismus MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- oxidativní fosforylace MeSH
- proteiny dánia pruhovaného MeSH
- reaktivní formy kyslíku metabolismus MeSH
- respirační komplex IV * metabolismus MeSH
- srdeční mitochondrie metabolismus MeSH
- vápník metabolismus MeSH
- vápníková signalizace * MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
In this study, we focused on an analysis of biguanides effects on mitochondrial enzyme activities, mitochondrial membrane potential and membrane permeability transition pore function. We used phenformin, which is more efficient than metformin, and evaluated its effect on rat liver mitochondria and isolated hepatocytes. In contrast to previously published data, we found that phenformin, after a 5 min pre-incubation, dose-dependently inhibits not only mitochondrial complex I but also complex II and IV activity in isolated mitochondria. The enzymes complexes inhibition is paralleled by the decreased respiratory control index and mitochondrial membrane potential. Direct measurements of mitochondrial swelling revealed that phenformin increases the resistance of the permeability transition pore to Ca(2+) ions. Our data might be in agreement with the hypothesis of Schäfer (1976) that binding of biguanides to membrane phospholipids alters membrane properties in a non-specific manner and, subsequently, different enzyme activities are modified via lipid phase. However, our measurements of anisotropy of fluorescence of hydrophobic membrane probe diphenylhexatriene have not shown a measurable effect of membrane fluidity with the 1 mM concentration of phenformin that strongly inhibited complex I activity. Our data therefore suggest that biguanides could be considered as agents with high efficacy but low specifity.
- MeSH
- biguanidy farmakologie MeSH
- fenformin farmakologie MeSH
- inhibitory enzymů farmakologie MeSH
- jaterní mitochondrie účinky léků enzymologie MeSH
- krysa rodu rattus MeSH
- metformin farmakologie MeSH
- potkani Wistar MeSH
- respirační komplex I antagonisté a inhibitory fyziologie MeSH
- respirační komplex II antagonisté a inhibitory fyziologie MeSH
- respirační komplex IV antagonisté a inhibitory fyziologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Alterations in mitochondrial parameters are an important hallmark of Huntington's disease (HD). The ubiquitous expression of mutant huntingtin raises the prospect that mitochondrial disturbances can also be detected and monitored through buccal epithelial cells. In a group of 34 patients with Huntington's disease and a group of 22 age-related healthy volunteers, respiratory complex I and IV protein quantities in buccal epithelial cells were measured using the dipstick immunocapture assay. The protein quantity of respiratory complex I correlates with age (r = 0.427, P = 0.026, FWE-P = 0.156) in the patient group, but not in the group of healthy subjects. Our non-invasive approach allows us to obtain valuable information for the studies of mitochondrial biochemical parameters in patients with neurodegenerative diseases and could also be useful in epidemiological studies.
- MeSH
- Huntingtonova nemoc metabolismus MeSH
- kachexie metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- respirační komplex I metabolismus MeSH
- respirační komplex IV metabolismus MeSH
- studie případů a kontrol MeSH
- ústní sliznice metabolismus MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
Early onset mitochondrial encephalo-cardiomyopathy due to isolated deficiency of ATP synthase is frequently caused by mutations in TMEM70 gene encoding enzyme-specific ancillary factor. Diminished ATP synthase results in low ATP production, elevated mitochondrial membrane potential and increased ROS production. To test whether the patient cells may react to metabolic disbalance by changes in oxidative phosphorylation system, we performed a quantitative analysis of respiratory chain complexes and intramitochondrial proteases involved in their turnover. SDS- and BN-PAGE Western blot analysis of fibroblasts from 10 patients with TMEM70 317-2A>G homozygous mutation showed a significant 82-89% decrease of ATP synthase and 50-162% increase of respiratory chain complex IV and 22-53% increase of complex III. The content of Lon protease, paraplegin and prohibitins 1 and 2 was not significantly changed. Whole genome expression profiling revealed a generalized upregulation of transcriptional activity, but did not show any consistent changes in mRNA levels of structural subunits, specific assembly factors of respiratory chain complexes, or in regulatory genes of mitochondrial biogenesis which would parallel the protein data. The mtDNA content in patient cells was also not changed. The results indicate involvement of posttranscriptional events in the adaptive regulation of mitochondrial biogenesis that allows for the compensatory increase of respiratory chain complexes III and IV in response to deficiency of ATP synthase.
- MeSH
- fibroblasty metabolismus patologie MeSH
- lidé MeSH
- membránové proteiny genetika MeSH
- messenger RNA genetika metabolismus MeSH
- mitochondriální DNA metabolismus MeSH
- mitochondriální proteiny genetika MeSH
- mitochondriální protonové ATPasy nedostatek metabolismus MeSH
- mitochondrie enzymologie genetika MeSH
- mutace genetika MeSH
- oxidativní fosforylace MeSH
- proteasy metabolismus MeSH
- respirační komplex III metabolismus MeSH
- respirační komplex IV metabolismus MeSH
- stanovení celkové genové exprese MeSH
- transport elektronů genetika MeSH
- up regulace * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- deficit pyruvátdehydrogenázového komplexu enzymologie patofyziologie MeSH
- dítě MeSH
- fibroblasty enzymologie MeSH
- jaterní mitochondrie enzymologie MeSH
- kojenec MeSH
- lidé MeSH
- pyruvátdehydrogenasový komplex patofyziologie MeSH
- respirační komplex IV metabolismus MeSH
- svalové mitochondrie enzymologie MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- Publikační typ
- kazuistiky MeSH
Vývoj a existenci specifických aktivit nervové buňky si nelze představit bez adekvátně strukturované nosné membrány. Začlenění funkčních proteinových komponent je kauzálně svázáno se stavbou lipidové dvojvrstvy která umožňuje nejen určitou prostorovou stabilitu (fixaci), ale současně i prostorovou návaznost, součinnost a variabilitu. Pohyb bílkovinných molekul v tekuté mozaice membrány je omezen jejich zakotvením do cytoskeletu. Ten má mechanicky podpůrný význam a hraje důležitou úlohu v přenosu informace do nitra buňky. U nervových buněk řídí interakce cytoskeletu a membrány výdej neurotransmitéru z presynaptických zakončení a recyklaci synaptických váčků. V souvislosti s hledáním markerů psychických poruch se předmětem intenzivního výzkumu stala i membrána červených krvinek, která má vysoce komplexní strukturu, srovnatelnou se strukturou membrán většiny eukaryotických buněk. Byly pozorovány četné biochemické abnormality červených krvinek při různých psychických poruchách, jako jsou změny v aktivitě některých membránově vázaných enzymů a receptoru, různé hladiny oxidativního stresu a změny ve složení lipidů.
Development and existence of specific activities of nerve cells are indispensable from the adequate structure of the supporting membrane. Integration of functional protein components determines the structure of lipid bilayer. It brings not only a certain special stability (fixation) but also a specific relationship, cooperation and variability among the components of the membrane. Movements of protein molecules within the fluid mosaic of the membrane are limited by their anchoring to the cytoskeleton. Cytoskeleton has mechanically supporting function and it plays an important role in the transmission of signals into the cell. In nerve cells interaction of cytoskeleton and membrane controls the release of neurotransmitter from the presynaptic terminals and recycling of synaptic vesicles. In relation to the quest for markers of psychic impairments, erythrocytal membrane became intensively studied. In its complex structure, comparable to the membrane of most of eukaryotic cells, biochemical abnormalities related to various psychic disorders were described: Changes in the activity of some membrane-bound enzymes and receptors, in the composition of lipids, and in different levels of oxidative stress.
- MeSH
- centrální nervový systém patologie MeSH
- dítě MeSH
- kojenec MeSH
- laktáty krev MeSH
- Leighova nemoc farmakoterapie metabolismus patologie MeSH
- lidé MeSH
- pyruvátdehydrogenasový komplex MeSH
- pyruváty krev MeSH
- respirační komplex IV MeSH
- sukcinát: cytochrom c oxidoreduktasa MeSH
- Check Tag
- dítě MeSH
- kojenec MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
Posterior polymorphous corneal dystrophy (PPCD) is a hereditary bilateral disorder affecting primarily the endothelium and Descemet's membrane (DM). The aim of this study was to determine the changes in the presence and localization of the alpha1-alpha6 collagen IV chains and alpha1, alpha2 collagen VIII chains in Czech patients with PPCD. Twelve corneal buttons from ten PPCD patients who underwent corneal grafting, as well as eight unaffected corneas, were used. Enzymatic indirect immunohistochemistry was performed on cryosections using antibodies against the alpha1-alpha6 collagen IV chains and alpha1, alpha2 collagen VIII chains. The intensity of the signal was examined separately in the basal membrane of the epithelium (BME), stroma and DM. More than 50% of PPCD specimens exhibited positivity for alpha1 and alpha2 collagen IV chains in the BME and in the posterior stroma, while no staining was detected in these areas in control specimens. The signal for the alpha1 and alpha2 collagen IV chains was more intense in DM of PPCD corneas compared to controls and it was shifted from the stromal side (in control tissue) to the endothelial side of DM (in the patients). A less intensive signal in PPCD corneas for the alpha3 and alpha5 chains in DM and an accumulation of alpha3-alpha5 in the posterior stroma in diseased corneas were the only differences in staining for the alpha3-alpha6 collagen IV chains. The alpha1 collagen VIII chain was detected on both the endothelial and the stromal sides of DM in 90% of patients with PPCD, compared with the prevailing localization on the stromal side of DM in control corneas. A change in the localization of the alpha2 collagen VIII chain in DM from vertically striated features in control specimens to double line positivity in the DM of PPCD corneas and positive staining in the posterior collagenous layer of four patients were also detected. In three PPCD patients a fibrous pannus located under the BME, positive for alpha1-alpha3, alpha5 collagen IV chains and alpha1 collagen VIII chain, was observed. The increased expression of the alpha1, alpha2 collagen IV and alpha1 collagen VIII chains and the change in their localization in DM may contribute to the increased endothelial proliferative capacity observed in PPCD patients.
- MeSH
- bazální membrána metabolismus patologie MeSH
- Bowmanova membrána metabolismus patologie MeSH
- dědičné dystrofie rohovky metabolismus patologie MeSH
- dospělí MeSH
- imunoenzymatické techniky MeSH
- kolagen typ VIII metabolismus MeSH
- kolagen typu IV metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- rohovka metabolismus MeSH
- senioři MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- práce podpořená grantem MeSH
