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1.
J Biol Regul Homeost Agents ; 34(1): 111-121, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32148012

RESUMO

During the menopause women may experience increased oxidative stress and decreased antioxidant capacity and, together with the decline of neurosteroids, this represents a risk factor for Alzheimer's disease. The aim of the present study was to test a functional food (FPP-ORI, Osato Research Institute, Gifu, Japan) on redox and mitochondrial efficiency in post-menopausal women. The study population consisting of 69 untreated post-menopausal women were given supplements as follows: Group A was given a multivitamin (MV) 1c 2 times a day, and group B was given FPP 4.5 g 2 times a day. Group C consisted of 23 fertile premenopausal women as the control group. The tests carried out on entry, and at 3 and 6 months were erythrocyte redox parameters, plasma oxidated proteins, brain-derived neurotrophic factor (BDNF) and peripheral blood mononuclear cell (PBMC) mitochondria cytochrome c oxidase Vmax activity. Menopausal women showed an increased malondialdehyde (MDA) (p<0.05 vs control) which was normalized by both treatments (p<0.05), but MV failed to do so in the BMI ≥26 subgroup (p<0.05). All other redox enzymes and BDNF were significantly lower in menopausal women and they responded only to FPP (p<0.05). Carbonyl protein level was higher in "BMI ≥ 26" subgroup (p<0.05) and reduced only by FPP (p<0.05). The PBMC cyclooxygenase to citrate synthase activity was reduced (<40%) in the menopausal group (p<0.01) and only FPP caused a significant restoration (p<0.05). Although preliminary, these data confirm the redox and mitochondrial dysfunction occurring in post-menopause and responsive to FPP but very poorly to high dosage antioxidants. This may lead to potential preventive opportunities in menopause-associated neurodegenerative disease.


Assuntos
Alimento Funcional , Mitocôndrias/patologia , Doenças Neurodegenerativas/epidemiologia , Pós-Menopausa , Antioxidantes/fisiologia , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Humanos , Japão , Leucócitos Mononucleares , Malondialdeído/metabolismo , Oxirredução , Estresse Oxidativo , Projetos Piloto , Fatores de Risco
2.
Inorg Chem ; 59(2): 1242-1255, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31910004

RESUMO

Cytochrome c oxidase (CcO) has a binuclear active site composed of a high-spin heme group and a tris-histidine-ligated copper ion (CuB). By using two different porphyrin models derived by Gunter (H2TPyPP) and us (H2TImPP), we have isolated several mono- and binuclear complexes including one carbonyl and three chloride derivatives which are determined by 100 K single-crystal X-ray. Low-temperature (4 K) EPR and multitemperature (295-25 K) Mössbauer investigations on the products not only confirmed the spin states of the two metal ions (S = 5/2 Fe3+ and S = 1/2 Cu2+) but also revealed the intermolecular interactions and intramolecular couplings which are in accordance with the crystal structural features.


Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/análise , Porfirinas/química , Cristalografia por Raios X , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Modelos Moleculares , Estrutura Molecular , Porfirinas/metabolismo , Temperatura Ambiente
3.
Nat Commun ; 11(1): 557, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31992699

RESUMO

Hydrogen sulfide (H2S) is involved in numerous pathophysiological processes and shares overlapping functions with CO and •NO. However, the importance of host-derived H2S in microbial pathogenesis is unknown. Here we show that Mtb-infected mice deficient in the H2S-producing enzyme cystathionine ß-synthase (CBS) survive longer with reduced organ burden, and that pharmacological inhibition of CBS reduces Mtb bacillary load in mice. High-resolution respirometry, transcriptomics and mass spectrometry establish that H2S stimulates Mtb respiration and bioenergetics predominantly via cytochrome bd oxidase, and that H2S reverses •NO-mediated inhibition of Mtb respiration. Further, exposure of Mtb to H2S regulates genes involved in sulfur and copper metabolism and the Dos regulon. Our results indicate that Mtb exploits host-derived H2S to promote growth and disease, and suggest that host-directed therapies targeting H2S production may be potentially useful for the management of tuberculosis and other microbial infections.


Assuntos
Sulfeto de Hidrogênio/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/patogenicidade , Animais , Cobre/metabolismo , Cistationina beta-Sintase/genética , Cistationina beta-Sintase/metabolismo , Citocinas/sangue , Modelos Animais de Doenças , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Metabolismo Energético , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Homeostase , Pulmão/patologia , Macrófagos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mycobacterium tuberculosis/genética , Células RAW 264.7 , Regulon , Enxofre/metabolismo , Transcriptoma , Tuberculose
4.
Adv Exp Med Biol ; 1232: 245-251, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893417

RESUMO

Skeletal muscle metabolic function is known to respond positively to endurance exercise interventions, such as marathon training. Studies investigating skeletal muscle have typically used muscle biopsy samples or magnetic resonance spectroscopy (MRS) to interrogate metabolic function. We aimed to non-invasively detect exercise-training-induced improvements in muscle function using broadband near-infrared spectroscopy (NIRS). We used NIRS to determine concentration changes in oxygenated haemoglobin (HbO2) and the oxidation state of cytochrome-c-oxidase (oxCCO) in gastrocnemius during arterial occlusion in 14 volunteers. We also used a cardio-pulmonary exercise test (CPET) to assess peak total body oxygen uptake (peakVO2; a measure of fitness). Measurements were made at baseline (BL) which was prior to a period of at least 16 weeks of training for the 2017 London Marathon, and then within 3 weeks after completion of the marathon, follow-up (FU). We observed an increase in locally measured muscle oxygen consumption and rate of oxCCO concentration change, but not in cardio-respiratory fitness measured as whole-body peak oxygen consumption (peakVO2).


Assuntos
Músculo Esquelético , Consumo de Oxigênio , Corrida , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Feminino , Humanos , Masculino , Músculo Esquelético/metabolismo , Oxiemoglobinas/metabolismo
5.
Adv Exp Med Biol ; 1232: 339-345, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893429

RESUMO

We used a miniature broadband NIRS system to monitor concentration changes in brain oxygenation (oxy- and deoxy- haemoglobin [HbO2], [HHb]) and oxidised cytochrome-c-oxidase ([oxCCO]) during a high +Gz acceleration, induced by a human centrifuge, on two healthy experienced volunteers (2 male, 34 and 37 years). We performed a sequence of several +Gz exposures that were terminated at the onset of visual symptoms (loss of peripheral vision). Systemic parameters were recorded (i.e. heart rate, blood pressure and arterial saturation), and brain tissue blood volume changes ([HbT] = [HbO2] + [HHb]) and oxygen delivery ([HbDiff] = [HbO2] - [HHb]) were calculated. Volunteer 1 demonstrated a decrease in [HbT] of -3.49 ± 0.02 µMol and [HbDiff] of -3.23 ± 0.44 µMol, and an increase of [oxCCO] of 0.42 ± 0.01µMol. Volunteer 2 demonstrated a decrease in [HbDiff] of -4.37 ± 0.23 µMol, and no significant change in [HbT] (0.53 ± 0.06 µMol) and [oxCCO] (0.09 ± 0.06 µMol). The variability of the brain metabolic response was related to the level of ischaemia, suggesting that suppression of metabolism was due to lack of glucose substrate delivery rather than oxygen availability.


Assuntos
Aceleração , Complexo IV da Cadeia de Transporte de Elétrons , Hemodinâmica , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Encéfalo/enzimologia , Encéfalo/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Voluntários Saudáveis , Humanos , Masculino , Estresse Oxidativo , Oximetria/instrumentação , Oxigênio/metabolismo
6.
Biochim Biophys Acta Bioenerg ; 1861(2): 148133, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31825807

RESUMO

The respiratory complexes are organized in supramolecular assemblies called supercomplexes thought to optimize cellular metabolism under physiological and pathological conditions. In this study, we used genetically and biochemically well characterized cells bearing the pathogenic microdeletion m.15,649-15,666 (ΔI300-P305) in MT-CYB gene, to investigate the effects of an assembly-hampered CIII on the re-organization of supercomplexes. First, we found that this mutation also affects the stability of both CI and CIV, and evidences the occurrence of a preferential structural interaction between CI and CIII2, yielding a small amount of active CI+CIII2 supercomplex. Indeed, a residual CI+CIII combined redox activity, and a low but detectable ATP synthesis driven by CI substrates are detectable, suggesting that the assembly of CIII into the CI+CIII2 supercomplex mitigates the detrimental effects of MT-CYB deletion. Second, measurements of oxygen consumption and ATP synthesis driven by NADH-linked and FADH2-linked substrates alone, or in combination, indicate a common ubiquinone pool for the two respiratory pathways. Finally, we report that prolonged incubation with rotenone enhances the amount of CI and CIII2, but reduces CIV assembly. Conversely, the antioxidant N-acetylcysteine increases CIII2 and CIV2 and partially restores respirasome formation. Accordingly, after NAC treatment, the rate of ATP synthesis increases by two-fold compared with untreated cell, while the succinate level, which is enhanced by the homoplasmic mutation, markedly decreases. Overall, our findings show that fine-tuning the supercomplexes stability improves the energetic efficiency of cells with the MT-CYB microdeletion.


Assuntos
Trifosfato de Adenosina/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/deficiência , Mitocôndrias/enzimologia , Membranas Mitocondriais/enzimologia , Consumo de Oxigênio , Animais , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Deleção de Genes , Mitocôndrias/genética , Oxirredução , Rotenona/farmacologia
7.
Food Chem ; 309: 125653, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31670116

RESUMO

This study used DNA barcoding and DNA mini-barcoding to test a variety of animal-derived food products sold in the Chinese market for potential mislabeling. Samples (52) including meat, poultry, and fish purchased from retail and online sources were examined. Regions of cytochrome C oxidase I (COI) gene (~650 bp) and 16S rRNA (~220 bp) were used as full- and mini-barcode markers, respectively. Approximately 94% (49 of 52) of the samples generated barcode sequences. The failure rate for full COI full-barcodes was 44%, but we obtained the 16S rRNA mini-barcode from 87% of the COI-failed cases. Overall, the survey revealed that 23% (12 of 52) of animal-derived products were mislabeled and, in most cases, contain undeclared species. Thus, regulatory measures and continuous monitoring for mislabeling of animal-derived products should be conducted.


Assuntos
Código de Barras de DNA Taxonômico/métodos , DNA/análise , Peixes/genética , Aves Domésticas/genética , Animais , China , DNA/isolamento & purificação , DNA/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/análise , Complexo IV da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Carne/análise , RNA Ribossômico 16S/análise , RNA Ribossômico 16S/metabolismo
8.
Food Chem ; 305: 125439, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31499287

RESUMO

Compared to the control longans, hydrogen peroxide (H2O2)-treated longans exhibited higher index of pulp breakdown, higher fruit respiration rate, higher activities of pulp phosphohexose isomerase (PGI), succinate dehydrogenase (SDH), cytochrome C oxidase (CCO), ascorbic acid oxidase (AAO) and polyphenol oxidase (PPO), but lower activity of pulp nicotinamide adenine dinucleotide kinase (NADK). H2O2-treated longans also exhibited lower total activities of pulp glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH), lower levels of pulp NADP(H), but higher levels of pulp NAD(H). These data indicated that H2O2-stimulated longan pulp breakdown was owing to a decreased proportion of pentose phosphate pathway (PPP), the increased proportions of Embden-Meyerhof-Parnas pathway (EMP), tricarboxylic acid (TCA) cycle and cytochrome pathway (CCP) in total respiratory pathways. These findings further revealed that H2O2 could enhance respiration rate, and thus accelerate pulp breakdown occurrence and shorten the shelf life of longan fruit.


Assuntos
Peróxido de Hidrogênio/farmacologia , Sapindaceae/efeitos dos fármacos , Aldeído Oxidase/metabolismo , Ciclo do Ácido Cítrico/efeitos dos fármacos , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Armazenamento de Alimentos , Frutas/metabolismo , Glucosefosfato Desidrogenase/metabolismo , Glicólise/efeitos dos fármacos , NAD/metabolismo , Via de Pentose Fosfato/efeitos dos fármacos , Sapindaceae/metabolismo
9.
Inorg Chem ; 58(20): 13933-13944, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31566371

RESUMO

Density functional vibrational frequency calculations have been performed on eight geometry optimized cytochrome c oxidase (CcO) dinuclear center (DNC) reaction cycle intermediates and on the oxymyoglobin (oxyMb) active site. The calculated Fe-O and O-O stretching modes and their frequency shifts along the reaction cycle have been compared with the available resonance Raman (rR) measurements. The calculations support the proposal that in state A[Fea33+-O2-•···CuB+] of CcO, O2 binds with Fea32+ in a similar bent end-on geometry to that in oxyMb. The calculations show that the observed 20 cm-1 shift of the Fea3-O stretching mode from the PR to F state is caused by the protonation of the OH- ligand on CuB2+ (PR[Fea34+═O2-···HO--CuB2+] → F[Fea34+═O2-···H2O-CuB2+]), and that the H2O ligand is still on the CuB2+ site in the rR identified F[Fea34+═O2-···H2O-CuB2+] state. Further, the observed rR band at 356 cm-1 between states PR and F is likely an O-Fea3-porphyrin bending mode. The observed 450 cm-1 low Fea3-O frequency mode for the OH active oxidized state has been reproduced by our calculations on a nearly symmetrically bridged Fea33+-OH-CuB2+ structure with a relatively long Fea3-O distance near 2 Å. Based on Badger's rule, the calculated Fea3-O distances correlate well with the calculated νFe-O-2/3 (νFe-O is the Fea3-O stretching frequency) with correlation coefficient R = 0.973.


Assuntos
Teoria da Densidade Funcional , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Ferro/química , Oxigênio/química , Biocatálise , Domínio Catalítico , Cristalografia por Raios X , Complexo IV da Cadeia de Transporte de Elétrons/química , Ferro/metabolismo , Ligantes , Modelos Moleculares , Oxigênio/metabolismo , Vibração
10.
Nat Commun ; 10(1): 4108, 2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31511525

RESUMO

Recent advance in cancer research sheds light on the contribution of mitochondrial respiration in tumorigenesis, as they efficiently produce ATP and oncogenic metabolites that will facilitate cancer cell growth. Here we show that a stabilizing factor for mitochondrial supercomplex assembly, COX7RP/COX7A2L/SCAF1, is abundantly expressed in clinical breast and endometrial cancers. Moreover, COX7RP overexpression associates with prognosis of breast cancer patients. We demonstrate that COX7RP overexpression in breast and endometrial cancer cells promotes in vitro and in vivo growth, stabilizes mitochondrial supercomplex assembly even in hypoxic states, and increases hypoxia tolerance. Metabolomic analyses reveal that COX7RP overexpression modulates the metabolic profile of cancer cells, particularly the steady-state levels of tricarboxylic acid cycle intermediates. Notably, silencing of each subunit of the 2-oxoglutarate dehydrogenase complex decreases the COX7RP-stimulated cancer cell growth. Our results indicate that COX7RP is a growth-regulatory factor for breast and endometrial cancer cells by regulating metabolic pathways and energy production.


Assuntos
Neoplasias da Mama/patologia , Carcinogênese/patologia , Neoplasias do Endométrio/metabolismo , Hipóxia/patologia , Mitocôndrias/metabolismo , Neoplasias da Mama/genética , Carcinogênese/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Neoplasias do Endométrio/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Hipóxia/metabolismo , Complexo Cetoglutarato Desidrogenase/metabolismo , Consumo de Oxigênio , Espécies Reativas de Oxigênio/metabolismo
11.
Acta Parasitol ; 64(3): 679-685, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31538303

RESUMO

PURPOSE: Cystic echinococcosis (CE), caused by the metacestode of Echinococcus granulosus, is highly endemic over large parts of Iran. The purpose of this study was to investigate the prevalence rate of hydatidosis and mitochondrial cox1 real-time PCR with high-resolution melting curve (HRM) analysis of E. granulosus isolated from human and livestock. METHODS: In this cross-sectional study, 61 formalin-fixed paraffin-embedded tissue isolates were collected from human CE cases and 83 hydatid cysts from the liver and lung lesions of the livestock in Khorasan Razavi province, Northeast Iran. DNA was extracted from each isolate and amplified by real-time PCR and analyzed using the HRM method. RESULTS: The HRM analysis using the cox1 gene of 40 E. granulosus human isolates showed that 35 (87.5%), 4 (10%), and 1 (2.5%) of the isolates were categorized as G1, G3, and G6 genotypes, respectively. Out of the total 1342 livestock inspected, 39 (4%) goats and 44(12%) cattle were found harboring hydatid cysts all belonging to E. granulosus sensu stricto. CONCLUSION: The results confirmed that the high prevalence of E. granulosus sensu stricto in intermediate hosts is remarkable in northeast of Iran coupled with the high prevalence of infection in livestock, which reinforced the need for hydatidosis control programs in this region.


Assuntos
Doenças dos Bovinos/parasitologia , Equinococose/parasitologia , Equinococose/veterinária , Echinococcus granulosus/isolamento & purificação , Complexo IV da Cadeia de Transporte de Elétrons/genética , Doenças das Cabras/parasitologia , Animais , Bovinos , Estudos Transversais , Echinococcus granulosus/classificação , Echinococcus granulosus/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Genótipo , Cabras , Humanos , Irã (Geográfico) , Filogenia , Reação em Cadeia da Polimerase em Tempo Real
12.
Anticancer Res ; 39(9): 4865-4876, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31519589

RESUMO

BACKGROUND/AIM: Hypoxia promotes tumor proliferation and metastasis in colorectal cancer (CRC). Since the tumor microenvironment is generally characterized by hypoxia, its understanding is important for cancer therapy. We hypothesized that hypoxia promotes the mitochondrial function, mobility, and proliferation of CRC by up-regulating peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). MATERIALS AND METHODS: To assess the effects of PGC-1α under hypoxia, we investigated the mitochondrial function, cell motility, and sphere formation as well as proliferation and apoptosis of CRC. RESULTS: Under hypoxia, we confirmed the increased expression of PGC-1α and reduced production of reactive oxygen species (ROS) by activating anti-oxidant enzymes. Also, up-regulation of PGC-1α enhanced the motility, sphere formation, and proliferation of CRC. Under the presence of the anti-cancer drug 5-fluorouracil (5FU), up-regulation of PGC-1α under hypoxia promoted resistance of CRC against 5FU-induced apoptosis. CONCLUSION: Targeting PGC-1α could to be a powerful strategy for CRC therapy.


Assuntos
Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Hipóxia/metabolismo , Mitocôndrias/genética , Mitocôndrias/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Apoptose , Catalase/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Neoplasias Colorretais/patologia , Resistencia a Medicamentos Antineoplásicos , Complexo I de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Modelos Biológicos , Fosforilação Oxidativa , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
13.
Int J Mol Sci ; 20(15)2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31387303

RESUMO

Copper is an essential cofactor for aerobic respiration, since it is required as a redox cofactor in Cytochrome c Oxidase (COX). This ancient and highly conserved enzymatic complex from the family of heme-copper oxidase possesses two copper sites: CuA and CuB. Biosynthesis of the oxidase is a complex, stepwise process that requires a high number of assembly factors. In this review, we summarize the state-of-the-art in the assembly of COX, with special emphasis in the assembly of copper sites. Assembly of the CuA site is better understood, being at the same time highly variable among organisms. We also discuss the current challenges that prevent the full comprehension of the mechanisms of assembly and the pending issues in the field.


Assuntos
Cobre/metabolismo , Heme/metabolismo , Oxirredutases/metabolismo , Animais , Transporte Biológico , Catálise , Cobre/química , Complexo IV da Cadeia de Transporte de Elétrons/química , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Heme/química , Humanos , Íons/química , Íons/metabolismo , Metalochaperonas/química , Metalochaperonas/metabolismo , Modelos Biológicos , Conformação Molecular , Oxirredução , Oxirredutases/química , Ligação Proteica
14.
Biochim Biophys Acta Bioenerg ; 1860(9): 717-723, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31374214

RESUMO

Cytochrome c oxidases (CcOs) in the respiratory chains of mitochondria and bacteria are primary consumers of molecular oxygen, converting it to water with the concomitant pumping of protons across the membrane to establish a proton electrochemical gradient. Despite a relatively well understood proton pumping mechanism of bacterial CcOs, the role of the H channel in mitochondrial forms of CcO remains debated. Here, we used site-directed mutagenesis to modify a central residue of the lower span of the H channel, Q413, in the genetically tractable yeast Saccharomyces cerevisiae. Exchange of Q413 to several different amino acids showed no effect on rates and efficiencies of respiratory cell growth, and redox potential measurements indicated minimal electrostatic interaction between the 413 locus and the nearest redox active component heme a. These findings clearly exclude a primary role of this section of the H channel in proton pumping in yeast CcO. In agreement with the experimental data, atomistic molecular dynamics simulations and continuum electrostatic calculations on wildtype and mutant yeast CcOs highlight potential bottlenecks in proton transfer through this route. Our data highlight the preference for neutral residues in the 413 locus, precluding sufficient hydration for formation of a proton conducting wire.


Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Canais Iônicos/fisiologia , Membranas Mitocondriais/metabolismo , Prótons , Saccharomyces cerevisiae/enzimologia , Complexo IV da Cadeia de Transporte de Elétrons/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , Transporte de Íons , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Mutação , Oxirredução , Bombas de Próton
15.
Insect Biochem Mol Biol ; 114: 103226, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31446033

RESUMO

The huge energy demand posed by insect flight activity is met by an efficient oxidative phosphorylation process that takes place within flight muscle mitochondria. In the major arbovirus vector Aedes aegypti, mitochondrial oxidation of pyruvate, proline and glycerol 3-phosphate (G3P) represent the major energy sources of ATP to sustain flight muscle energy demand. Although adenylates exert critical regulatory effects on several mitochondrial enzyme activities, the potential consequences of altered adenylate levels to G3P oxidation remains to be determined. Here, we report that mitochondrial G3P oxidation is controlled by adenylates through allosteric regulation of cytochrome c oxidase (COX) activity in A. aegypti flight muscle. We observed that ADP significantly activated respiratory rates linked to G3P oxidation, in a protonmotive force-independent manner. Kinetic analyses revealed that ADP activates respiration through a slightly cooperative mechanism. Despite adenylates caused no effects on G3P-cytochrome c oxidoreductase activity, COX activity was allosterically activated by ADP. Conversely, ATP exerted powerful inhibitory effects on respiratory rates linked to G3P oxidation and on COX activity. We also observed that high energy phosphate recycling mechanisms did not contribute to the regulatory effects of adenylates on COX activity or G3P oxidation. We conclude that mitochondrial G3P oxidation in A. aegypti flight muscle is regulated by adenylates through the allosteric modulation of COX activity, underscoring the bioenergetic relevance of this novel mechanism and the potential consequences for mosquito dispersal.


Assuntos
Aedes/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Glicerofosfatos/metabolismo , Mitocôndrias/metabolismo , Miofibrilas/metabolismo , Regulação Alostérica , Animais , Respiração Celular , Feminino , Oxirredução
16.
BMC Neurosci ; 20(1): 34, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31307382

RESUMO

BACKGROUND: Emerging data suggests that volatile anesthetic agents may have organ protection properties in the setting of critical illness. The purpose of this study was to better understand the effect of inflammation on cerebral subcellular energetics in animals exposed to two different anesthetic agents-a GABA agonist (propofol) and a volatile agent (isoflurane). RESULTS: Forty-eight Sprague-Dawley rats were anesthetized with isoflurane or propofol. In each group, rats were randomized to celiotomy and closure (sham) or cecal ligation and puncture (inflammation [sepsis model]) for 8 h. Brain tissue oxygen saturation and the oxidation state of cytochrome aa3 were measured. Brain tissue was extracted using the freeze-blow technique. All rats experienced progressive increases in tissue oxygenation and cytochrome aa3 reduction over time. Inflammation had no impact on cytochrome aa3, but isoflurane caused significant cytochrome aa3 reduction. During isoflurane (not propofol) anesthesia, inflammation led to an increase in lactate (+ 0.64 vs. - 0.80 mEq/L, p = 0.0061). There were no differences in ADP:ATP ratios between groups. In the isoflurane (not propofol) group, inflammation increased the expression of hypoxia-inducible factor-1α (62%, p = 0.0012), heme oxygenase-1 (67%, p = 0.0011), and inducible nitric oxide synthase (31%, p = 0.023) in the brain. Animals exposed to inflammation and isoflurane (but not propofol) exhibited increased expression of protein carbonyls (9.2 vs. 7.0 nM/mg protein, p = 0.0050) and S-nitrosylation (49%, p = 0.045) in the brain. RNA sequencing identified an increase in heat shock protein 90 and NF-κß inhibitor mRNA in the inflammation/isoflurane group. CONCLUSIONS: In the setting of inflammation, rats exposed to isoflurane show increased hypoxia-inducible factor-1α expression despite a lack of hypoxia, increased oxidative stress in the brain, and increased serum lactate, all of which suggest a relative increase in anaerobic metabolism compared to propofol. Differences in oxidative stress as well as heat shock protein 90 and NF-κß inhibitor may account for the differential expression of cerebral hypoxia-inducible factor-1α during inflammation.


Assuntos
Encéfalo/metabolismo , Inflamação/metabolismo , Isoflurano/administração & dosagem , Propofol/administração & dosagem , Tiflite/metabolismo , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Anestésicos Inalatórios , Animais , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Proteínas de Choque Térmico HSP90/metabolismo , Heme Oxigenase (Desciclizante)/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Isoflurano/farmacologia , Ácido Láctico/metabolismo , Masculino , NF-kappa B/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Oxirredução , Oxigênio/metabolismo , Propofol/farmacologia , Carbonilação Proteica/efeitos dos fármacos , Ratos
17.
Cells ; 8(7)2019 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-31248014

RESUMO

After billions of years of evolution, mitochondrion retains its own genome, which gets expressed in mitochondrial matrix. Mitochondrial translation machinery rather differs from modern bacterial and eukaryotic cytosolic systems. Any disturbance in mitochondrial translation drastically impairs mitochondrial function. In budding yeast Saccharomyces cerevisiae, deletion of the gene coding for mitochondrial translation initiation factor 3 - AIM23, leads to an imbalance in mitochondrial protein synthesis and significantly delays growth after shifting from fermentable to non-fermentable carbon sources. Molecular mechanism underlying this adaptation to respiratory growth was unknown. Here, we demonstrate that slow adaptation from glycolysis to respiration in the absence of Aim23p is accompanied by a gradual increase of cytochrome c oxidase activity and by increased levels of Tma19p protein, which protects mitochondria from oxidative stress.


Assuntos
Adaptação Fisiológica , Fatores de Iniciação em Eucariotos/genética , Mitocôndrias/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiologia , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Deleção de Genes , Regulação Fúngica da Expressão Gênica/fisiologia , Genes Mitocondriais/genética , Glicólise/fisiologia , Mitocôndrias/genética , Estresse Oxidativo/fisiologia , Biossíntese de Proteínas/fisiologia
18.
Biochim Biophys Acta Bioenerg ; 1860(8): 618-627, 2019 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251900

RESUMO

Ustilago maydis is an aerobic basidiomycete that depends on oxidative phosphorylation for its ATP supply, pointing to the mitochondrion as a key player in its energy metabolism. Mitochondrial respiratory complexes I, III2, and IV occur in supramolecular structures named respirasome. In this work, we characterized the subunit composition and the kinetics of NADH:Q oxidoreductase activity of the digitonine-solubilized respirasome (1600 kDa) and the free-complex I (990 kDa). In the presence of 2,6-dimethoxy-1,4-benzoquinone (DBQ) and cytochrome c, both the respirasome NADH:O2 and the NADH:DBQ oxidoreductase activities were inhibited by rotenone, antimycin A or cyanide. A value of 2.4 for the NADH oxidized/oxygen reduced ratio was determined for the respirasome activity, while ROS production was less than 0.001% of the oxygen consumption rate. Analysis of the NADH:DBQ oxidoreductase activity showed that respirasome was 3-times more active and showed higher affinity than free-complex I. The results suggest that the contacts between complexes I, III2 and IV in the respirasome increase the catalytic efficiency of complex I and regulate its activity to prevent ROS production.


Assuntos
Complexo de Proteínas da Cadeia de Transporte de Elétrons/química , Mitocôndrias/enzimologia , NADH Desidrogenase/metabolismo , Ustilago/enzimologia , Basidiomycota , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Complexo I de Transporte de Elétrons/metabolismo , Complexo III da Cadeia de Transporte de Elétrons/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Mitocôndrias/metabolismo , Oxirredução , Fosforilação Oxidativa , Espécies Reativas de Oxigênio/antagonistas & inibidores , Ustilago/metabolismo
19.
J Pharmacol Exp Ther ; 370(2): 308-317, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31160469

RESUMO

Protamine sulfate (PS) is widely used in heart surgery as an antidote for heparin, albeit its pharmacological effects are not fully understood and applications are often accompanied by unwanted side effects. Here we show the effect of PS on mitochondrial bioenergetics profile resulting in mitochondrial reactive oxygen species (ROS) production. Polarographic measurements were performed in parallel to membrane potential and ROS measurements by FACS analyzer using tetramethylrhodamine ethyl ester and MitoSOX fluorescent dyes, respectively. PS inhibited intact rat heart mitochondrial respiration (stimulated by ADP) to 76% (P < 0.001) from the baseline of 51.6 ± 6.9 to 12.4 ± 2.3 nmol O2⋅min-1⋅ml-1 The same effect was found when respiration was inhibited by antimycin A (101.0 ± 8.9 vs. 38.0 ± 9.9 nmol O2 ⋅min-1⋅ml-1, P < 0.001) and later stimulated by substrates of cytochrome oxidase (CytOx) i.e., ascorbate and tetramethyl phenylene diamine, suggesting that PS exerted its effect through inhibition of CytOx activity. Furthermore, the inhibition of mitochondrial respiration by PS was concentration dependent and accompanied by hyperpolarization of the mitochondrial membrane potential (Δψ m), i.e., 18% increase at 50 µg/ml and an additional 3.3% increase at 250 µg/ml PS compared with control. This effect was associated with a strong consequent increase in the production of ROS, i.e., 85% and 88.6% compared with control respectively. We propose that this excessive increase in ROS concentrations results in mitochondrial dysfunction and thus might relate to the "protamine reaction," contributing to the development of various cardiovascular adverse effects.


Assuntos
Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Protaminas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Animais , Respiração Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Masculino , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Miocárdio/citologia , Miocárdio/metabolismo , Ratos , Ratos Wistar
20.
Photobiomodul Photomed Laser Surg ; 37(6): 336-341, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31107170

RESUMO

Objective: Several reports claim that the enzyme cytochrome c oxidase (CCO) is the primary absorber for red-to-near-infrared (R-NIR) light in cells and causal for mitochondrial adenosine triphosphate (ATP) upregulation, and that pulsed R-NIR light has frequent therapeutic effects, which are superior to those of the continuous wave (CW) mode used in low-level light therapy (LLLT). Background data: Convincing evidence that the absorption of R-NIR photons by CCO is involved in mitochondrial ATP upregulations as well as a coherent explanation for the superiority of the pulsed irradiation mode is presently lacking in the literature. Methods: A comprehensive literature search and rigorous analysis of the data published on the idea that CCO is the primary absorber for R-NIR light, and of the claim that the effectivity of the pulsed irradiation mode can be derived from the absorption of R-NIR photons by CCO, reveal a number of severe inconsistencies. Results: A systematical analysis covering both the theory that CCO is the primary acceptor for R-NIR light and of its use to interpret differences between the biological effect of pulsed light and CW casts doubt on the general validity of the CCO-based hypothesis. Instead, we are offered a simple and conflict-free model accounting for both ATP upregulation and superiority of the pulsed mode in LLLT, which is in agreement with the results of recent laboratory experiments. Conclusions: CCO is not the primary acceptor for R-NIR light.


Assuntos
Trifosfato de Adenosina/metabolismo , Comunicação Celular/efeitos da radiação , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Terapia com Luz de Baixa Intensidade , Mitocôndrias/metabolismo , Fótons , Regulação para Cima
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