The mitochondrial respiratory chain (MRC) complex III (CIII) associates with complexes I and IV (CI and CIV) into supercomplexes. We identified a novel homozygous missense mutation (c.665G>C; p.Gly222Ala) in UQCRC2 coding for structural subunit Core 2 in a patient with severe encephalomyopathy. The structural data suggest that the Gly222Ala exchange might result in an altered spatial arrangement in part of the UQCRC2 subunit, which could impact specific protein-protein interactions. Accordingly, we have found decreased levels of CIII and accumulation of CIII-specific subassemblies comprising MT-CYB, UQCRB, UQCRQ, UQCR10 and CYC1 subunits, but devoid of UQCRC1, UQCRC2, and UQCRFS1 in the patient's fibroblasts. The lack of UQCRC1 subunit-containing subassemblies could result from an impaired interaction with mutant UQCRC2Gly222Ala and subsequent degradation of both subunits by mitochondrial proteases. Indeed, we show an elevated amount of matrix CLPP protease, suggesting the activation of the mitochondrial protein quality control machinery in UQCRC2Gly222Ala fibroblasts. In line with growing evidence, we observed a rate-limiting character of CIII availability for the supercomplex formation, accompanied by a diminished amount of CI. Furthermore, we found impaired electron flux between CI and CIII in skeletal muscle and fibroblasts of the UQCRC2Gly222Ala patient. The ectopic expression of wild-type UQCRC2 in patient cells rescued maximal respiration rate, demonstrating the deleterious effect of the mutation on MRC. Our study expands the phenotypic spectrum of human disease caused by CIII Core protein deficiency, provides insight into the assembly pathway of human CIII, and supports the requirement of assembled CIII for a proper accumulation of CI.

• MeSH
• fibroblasty patologie   MeSH
• homozygot MeSH
• kosterní svaly patologie   MeSH
• lidé MeSH
• missense mutace genetika   MeSH
• mitochondriální encefalomyopatie genetika   MeSH
• mitochondriální proteiny genetika   MeSH
• mitochondrie genetika   MeSH
• respirační komplex III genetika   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The functional role of CD36 protein detected in mitochondrial fractions in long chain fatty acid (LCFA) oxidation is unclear due to conflicting results obtained in Cd36 knockout mice and experiments using sulfo-N-succinimidyl oleate (SSO) for inhibition of CD36 mediated LCFA transport. We investigated effect of SSO on mitochondrial respiration and found that SSO substantially inhibits not only LCFA oxidation, but also oxidation of flavoprotein- and NADH-dependent substrates and generation of mitochondrial membrane potential. Experiments in rat liver, heart and kidney mitochondria demonstrated a direct effect on mitochondrial respiratory chain with the most pronounced inhibition of the complex III (IC(50) 4microM SSO). The results presented here show that SSO is a potent and irreversible inhibitor of mitochondrial respiratory chain. Copyright 2010. Published by Elsevier Inc.

• MeSH
• antigeny CD36 genetika   metabolismus   účinky léků   MeSH
• biologický transport účinky léků   MeSH
• buněčné dýchání účinky léků   MeSH
• krysa rodu rattus MeSH
• kyseliny olejové farmakologie   MeSH
• mastné kyseliny metabolismus   MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• mitochondrie enzymologie   účinky léků   MeSH
• myši knockoutované MeSH
• myši MeSH
• potkani inbrední WKY MeSH
• respirační komplex III antagonisté a inhibitory   MeSH
• sukcinimidy farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• alkoholická kardiomyopatie patofyziologie   MeSH
• cytochromy MeSH
• energetický metabolismus MeSH
• fosforylace MeSH
• králíci MeSH
• přenos energie MeSH
• respirační komplex IV MeSH
• srdeční mitochondrie metabolismus   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH

Introduction and Objectives: One of the characteristic changes of tumor formation is accumulation of genetic disorders in mitochondrial and nuclear genome. Mitochondrial disorders, from its side, are responsible for failure of metabolism, apoptosis, cell growth, formation of reactive oxygen species, etc. Overprpoduction of reactive oxygen species (ROS) significantly impacts the respiration chain enzymes and entirely the antioxidant system of mitochondria. Finally this may become a favorable condition for normal cells transformation. The purpose of the presented work was to study the mitochondrial defects and to establish their role in prostate cancer development. Results: Experimental results demonstrate significant increase of the activity of mitochondrial succinate dehydrogenaze (complex II) of the malignant epithelial cells of prostate, and slight changes in cytochrome oxydase (complex IV) activity. Also significant activation of the antioxidant system (glutathione-dependant system) of mitochondria in prostate malignant epithelial cells was revealed. Conclusion: The above mentioned mitochondrial changes (II and IV complexes of respiration chain, activity of the antioxidant system) partially demonstrate the alterations in mitochondrial energy metabolism, which from its side, may indicate to resistance of prostate cancer cells and correspondingly to intensification of proliferation processes.

• MeSH
• citrátový cyklus MeSH
• glutathion metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mitochondriální DNA * genetika   metabolismus   genetika   izolace a purifikace   metabolismus   MeSH
• nádory prostaty * genetika   MeSH
• přenos energie MeSH
• reaktivní formy kyslíku * MeSH
• respirační komplex IV MeSH
• senioři MeSH
• sukcinátdehydrogenasa * diagnostické užití   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH

The Philopterus Complex includes several lineages of lice that occur on birds. The complex includes the genera Philopterus (Nitzsch, 1818; Psocodea: Philopteridae), Philopteroides (Mey, 2004; Psocodea: Philopteridae), and many other lineages that have sometimes been regarded as separate genera. Only a few studies have investigated the phylogeny of this complex, all of which are based on morphological data. Here we evaluate the utility of nuclear and mitochondrial loci for recovering the phylogeny within this group. We obtained phylogenetic trees from 39 samples of the Philopterus Complex (Psocodea: Philopteridae), using sequences of two nuclear (hyp and TMEDE6) and one mitochondrial (COI) marker. We evaluated trees derived from these genes individually as well as from concatenated sequences. All trees show 20 clearly demarcated taxa (i.e., putative species) divided into five well-supported clades. Percent sequence divergence between putative species (~5-30%) for the COI gene tended to be much higher than those for the nuclear genes (~1-15%), as expected. In cases where species are described, the lineages identified based on molecular divergence correspond to morphologically defined species. In some cases, species that are host generalists exhibit additional underlying genetic variation and such cases need to be explored by further future taxonomic revisions of the Philopterus Complex.

• MeSH
• buněčné jádro MeSH
• fylogeneze * MeSH
• genetické markery MeSH
• hmyzí proteiny analýza   MeSH
• Ischnocera klasifikace   genetika   MeSH
• mitochondriální proteiny analýza   MeSH
• respirační komplex IV analýza   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Isolated complex I deficiency is a common biochemical phenotype observed in pediatric mitochondrial disease and often arises as a consequence of pathogenic variants affecting one of the ∼65 genes encoding the complex I structural subunits or assembly factors. Such genetic heterogeneity means that application of next-generation sequencing technologies to undiagnosed cohorts has been a catalyst for genetic diagnosis and gene-disease associations. We describe the clinical and molecular genetic investigations of four unrelated children who presented with neuroradiological findings and/or elevated lactate levels, highly suggestive of an underlying mitochondrial diagnosis. Next-generation sequencing identified bi-allelic variants in NDUFA6, encoding a 15 kDa LYR-motif-containing complex I subunit that forms part of the Q-module. Functional investigations using subjects' fibroblast cell lines demonstrated complex I assembly defects, which were characterized in detail by mass-spectrometry-based complexome profiling. This confirmed a marked reduction in incorporated NDUFA6 and a concomitant reduction in other Q-module subunits, including NDUFAB1, NDUFA7, and NDUFA12. Lentiviral transduction of subjects' fibroblasts showed normalization of complex I. These data also support supercomplex formation, whereby the ∼830 kDa complex I intermediate (consisting of the P- and Q-modules) is in complex with assembled complex III and IV holoenzymes despite lacking the N-module. Interestingly, RNA-sequencing data provided evidence that the consensus RefSeq accession number does not correspond to the predominant transcript in clinically relevant tissues, prompting revision of the NDUFA6 RefSeq transcript and highlighting not only the importance of thorough variant interpretation but also the assessment of appropriate transcripts for analysis.

• MeSH
• alely MeSH
• fenotyp MeSH
• fibroblasty patologie   MeSH
• genetická heterogenita MeSH
• kojenec MeSH
• lidé MeSH
• mitochondriální nemoci genetika   MeSH
• mitochondriální proteiny genetika   MeSH
• mitochondrie genetika   MeSH
• mutace genetika   MeSH
• respirační komplex I nedostatek   genetika   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Maternally inherited complex I deficiencies due to mutations in MT-ND genes represent a heterogeneous group of multisystem mitochondrial disorders (MD) with a unfavourable prognosis. The aim of the study was to characterize the impact of the mutations in MT-ND genes, including the novel m.13091 T > C variant, on the course of the disease, and to analyse the activities of respiratory chain complexes, the amount of protein subunits, and the mitochondrial energy-generating system (MEGS) in available muscle biopsies and cultivated fibroblasts. METHODS: The respiratory chain complex activities were measured by spectrophotometry, MEGS were analysed using radiolabelled substrates, and protein amount by SDS-PAGE or BN-PAGE in muscle or fibroblasts. RESULTS: In our cohort of 106 unrelated families carrying different mtDNA mutations, we found heteroplasmic mutations in the genes MT-ND1, MT-ND3, and MT-ND5, including the novel variant m.13091 T > C, in 13 patients with MD from 12 families. First symptoms developed between early childhood and adolescence and progressed to multisystem disease with a phenotype of Leigh or MELAS syndromes. MRI revealed bilateral symmetrical involvement of deep grey matter typical of Leigh syndrome in 6 children, cortical/white matter stroke-like lesions suggesting MELAS syndrome in 3 patients, and a combination of cortico-subcortical lesions and grey matter involvement in 4 patients. MEGS indicated mitochondrial disturbances in all available muscle samples, as well as a significantly decreased oxidation of [1-14C] pyruvate in fibroblasts. Spectrophotometric analyses revealed a low activity of complex I and/or complex I + III in all muscle samples except one, but the activities in fibroblasts were mostly normal. No correlation was found between complex I activities and mtDNA mutation load, but higher levels of heteroplasmy were generally found in more severely affected patients. CONCLUSIONS: Maternally inherited complex I deficiencies were found in 11% of families with mitochondrial diseases in our region. Six patients manifested with Leigh, three with MELAS. The remaining four patients presented with an overlap between these two syndromes. MEGS, especially the oxidation of [1-14C] pyruvate in fibroblasts might serve as a sensitive indicator of functional impairment due to MT-ND mutations. Early onset of the disease and higher level of mtDNA heteroplasmy were associated with a worse prognosis.

• MeSH
• biopsie MeSH
• dítě MeSH
• dospělí MeSH
• fibroblasty metabolismus   MeSH
• kojenec MeSH
• kosterní svaly metabolismus   MeSH
• kultivované buňky MeSH
• Leighova nemoc genetika   MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• mitochondriální DNA * MeSH
• mitochondriální nemoci genetika   MeSH
• mladiství MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• mutace * MeSH
• novorozenec MeSH
• respirační komplex I nedostatek   genetika   metabolismus   MeSH
• syndrom MELAS genetika   MeSH
• věk při počátku nemoci MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• novorozenec 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
• upregulace * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• cytochromy c fyziologie   MeSH
• kyslík metabolismus   MeSH
• mitochondrie enzymologie   MeSH
• protony MeSH
• respirační komplex IV analýza   fyziologie   chemie   MeSH
• transport elektronů genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• přehledy MeSH

Genetic screens have been used extensively to probe interactions between nuclear genes and their impact on phenotypes. Probing interactions between mitochondrial genes and their phenotypic outcome, however, has not been possible due to a lack of tools to map the responsible polymorphisms. Here, using a toolkit we previously established in Drosophila, we isolate over 300 recombinant mitochondrial genomes and map a naturally occurring polymorphism at the cytochrome c oxidase III residue 109 (CoIII109) that fully rescues the lethality and other defects associated with a point mutation in cytochrome c oxidase I (CoIT300I). Through lipidomics profiling, biochemical assays and phenotypic analyses, we show that the CoIII109 polymorphism modulates cardiolipin binding to prevent complex IV instability caused by the CoIT300I mutation. This study demonstrates the feasibility of genetic interaction screens in animal mitochondrial DNA. It unwraps the complex intra-genomic interplays underlying disorders linked to mitochondrial DNA and how they influence disease expression.

• MeSH
• Drosophila genetika   MeSH
• kardiolipiny * genetika   metabolismus   MeSH
• mitochondriální DNA * genetika   metabolismus   MeSH
• mitochondrie genetika   metabolismus   MeSH
• respirační komplex IV metabolismus   MeSH
• umělé letální mutace MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH