RESUMEN

Classic galactosemia is an inborn error of metabolism caused by mutations in the GALT gene resulting in the diminished activity of the galactose-1-phosphate uridyltransferase enzyme. This reduced GALT activity leads to the buildup of the toxic intermediate galactose-1-phosphate and a decrease in ATP levels upon exposure to galactose. In this work, we focused our attention on mitochondrial oxidative phosphorylation in the context of this metabolic disorder. We observed that galactose-1-phosphate accumulation reduced respiratory rates in vivo and changed mitochondrial function and morphology in yeast models of galactosemia. These alterations are harmful to yeast cells since the mitochondrial retrograde response is activated as part of the cellular adaptation to galactose toxicity. In addition, we found that galactose-1-phosphate directly impairs cytochrome c oxidase activity of mitochondrial preparations derived from yeast, rat liver, and human cell lines. These results highlight the evolutionary conservation of this biochemical effect. Finally, we discovered that two compounds - oleic acid and dihydrolipoic acid - that can improve the growth of cell models of mitochondrial diseases, were also able to improve galactose tolerance in this model of galactosemia. These results reveal a new molecular mechanism relevant to the pathophysiology of classic galactosemia - galactose-1-phosphate-dependent mitochondrial dysfunction - and suggest that therapies designed to treat mitochondrial diseases may be repurposed to treat galactosemia.

Asunto(s)

Complejo IV de Transporte de Electrones , Galactosemias , Galactosafosfatos , Mitocondrias , Galactosemias/metabolismo , Galactosemias/patología , Galactosemias/genética , Galactosafosfatos/metabolismo , Humanos , Animales , Ratas , Mitocondrias/metabolismo , Mitocondrias/patología , Mitocondrias/efectos de los fármacos , Complejo IV de Transporte de Electrones/metabolismo , Complejo IV de Transporte de Electrones/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Fosforilación Oxidativa/efectos de los fármacos , UTP-Hexosa-1-Fosfato Uridililtransferasa/metabolismo , UTP-Hexosa-1-Fosfato Uridililtransferasa/genética , Galactosa/metabolismo

RESUMEN

The efficiency of the DNA barcoding relies on sequencing fragment of the Cytochrome C Subunit I (COI) gene, which has been claimed as a tool to biodiversity identification from distinct groups. Accordingly, the goal of this study was to identify juvenile fish species along an estuary of Caeté River in the Brazilian Blue Amazon based on. For this purpose, we applied the DNA barcoding and discuss this approach as a tool for discrimination of species in early ontogenetic stages. A 500-bp fragment was obtained from 74 individuals, belonging to 23 species, 20 genera, 13 families and seven orders. About 70% of the 46 haplotypes revealed congruence between morphological and molecular species identification, while 8% of them failed in identification of taxa and 22% demonstrated morphological misidentification. These results proved that COI fragments were effective to diagnose fish species at early life stages, allowing identifying all samples to a species-specific status, except for some taxa whose COI sequences remain unavailable in public databases. Therefore, we recommend the incorporation of DNA barcoding to provide additional support to traditional identification, especially in morphologically controversial groups. In addition, periodic updates and comparative analyses in public COI datasets are encouraged.

Asunto(s)

Código de Barras del ADN Taxonómico , Estuarios , Humanos , Animales , Código de Barras del ADN Taxonómico/métodos , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Filogenia , Peces , ADN/genética

RESUMEN

The marine archaeon Methanosarcina acetivorans contains a putative NAD + -independent d-lactate dehydrogenase (D-iLDH/glycolate oxidase) encoded by the MA4631 gene, belonging to the FAD-oxidase C superfamily. Nucleotide sequences similar to MA4631 gene, were identified in other methanogens and Firmicutes with >90 and 35-40% identity, respectively. Therefore, the lactate metabolism in M. acetivorans is reported here. Cells subjected to intermittent pulses of oxygen (air-adapted; AA-Ma cells) consumed lactate only in combination with acetate, increasing methane production and biomass yield. In AA-Ma cells incubated with d-lactate plus [14C]-l-lactate, the radioactive label was found in methane, CO2 and glycogen, indicating that lactate metabolism fed both methanogenesis and gluconeogenesis. Moreover, d-lactate oxidation was coupled to O2-consumption which was sensitive to HQNO; also, AA-Ma cells showed high transcript levels of gene dld and those encoding subunits A (MA1006) and B (MA1007) of a putative cytochrome bd quinol oxidase, compared to anaerobic control cells. An E. coli mutant deficient in dld complemented with the MA4631 gene, grew with d-lactate as carbon source and showed membrane-bound d-lactate:quinone oxidoreductase activity. The product of the MA4631 gene is a FAD-containing monomer showing activity of iLDH with preference to d-lactate. The results suggested that air adapted M. acetivorans is able to co-metabolize lactate and acetate with associated oxygen consumption by triggering the transcription and synthesis of the D-iLDH and a putative cytochrome bd: methanophenazine (quinol) oxidoreductase. Biomass generation and O2 consumption, suggest a potentially new oxygen detoxification mechanism coupled to energy conservation in this methanogen.

Asunto(s)

Complejo IV de Transporte de Electrones , Oxígeno , Complejo IV de Transporte de Electrones/metabolismo , Oxígeno/metabolismo , Methanosarcina/genética , Methanosarcina/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Oxidorreductasas/metabolismo , Metano/metabolismo , Citocromos/metabolismo , Acetatos , Lactatos/metabolismo

RESUMEN

Mitochondrial translation is a highly regulated process, and newly synthesized mitochondrial products must first associate with several nuclear-encoded auxiliary factors to form oxidative phosphorylation complexes. The output of mitochondrial products should therefore be in stoichiometric equilibrium with the nuclear-encoded products to prevent unnecessary energy expense or the accumulation of pro-oxidant assembly modules. In the mitochondrial DNA of Saccharomyces cerevisiae, COX1 encodes subunit 1 of the cytochrome c oxidase and COB the central core of the cytochrome bc1 electron transfer complex; however, factors regulating the expression of these mitochondrial products are not completely described. Here, we identified Mrx9p as a new factor that controls COX1 and COB expression. We isolated MRX9 in a screen for mitochondrial factors that cause poor accumulation of newly synthesized Cox1p and compromised transition to the respiratory metabolism. Northern analyses indicated lower levels of COX1 and COB mature mRNAs accompanied by an accumulation of unprocessed transcripts in the presence of excess Mrx9p. In a strain devoid of mitochondrial introns, MRX9 overexpression did not affect COX1 and COB translation or respiratory adaptation, implying Mrx9p regulates processing of COX1 and COB RNAs. In addition, we found Mrx9p was localized in the mitochondrial inner membrane, facing the matrix, as a portion of it cosedimented with mitoribosome subunits and its removal or overexpression altered Mss51p sedimentation. Finally, we showed accumulation of newly synthesized Cox1p in the absence of Mrx9p was diminished in cox14 null mutants. Taken together, these data indicate a regulatory role of Mrx9p in COX1 RNA processing.

Asunto(s)

Complejo III de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Complejo III de Transporte de Electrones/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Fosforilación Oxidativa , ARN/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo

RESUMEN

Mutations in the mitochondrial genome (mtDNA) are ubiquitous in humans and can lead to a broad spectrum of disorders. However, due to the presence of multiple mtDNA molecules in the cell, co-existence of mutant and wild-type mtDNAs (termed heteroplasmy) can mask disease phenotype unless a threshold of mutant molecules is reached. Importantly, the mutant mtDNA level can change across lifespan as mtDNA segregates in an allele- and cell-specific fashion, potentially leading to disease. Segregation of mtDNA is mainly evident in hepatic cells, resulting in an age-dependent increase of mtDNA variants, including non-synonymous potentially deleterious mutations. Here we modeled mtDNA segregation using a well-established heteroplasmic mouse line with mtDNA of NZB/BINJ and C57BL/6N origin on a C57BL/6N nuclear background. This mouse line showed a pronounced age-dependent NZB mtDNA accumulation in the liver, thus leading to enhanced respiration capacity per mtDNA molecule. Remarkably, liver-specific atg7 (autophagy related 7) knockout abolished NZB mtDNA accumulat ion, resulting in close-to-neutral mtDNA segregation through development into adulthood. prkn (parkin RBR E3 ubiquitin protein ligase) knockout also partially prevented NZB mtDNA accumulation in the liver, but to a lesser extent. Hence, we propose that age-related liver mtDNA segregation is a consequence of macroautophagic clearance of the less-fit mtDNA. Considering that NZB/BINJ and C57BL/6N mtDNAs have a level of divergence comparable to that between human Eurasian and African mtDNAs, these findings have potential implications for humans, including the safe use of mitochondrial replacement therapy.Abbreviations: Apob: apolipoprotein B; Atg1: autophagy-related 1; Atg7: autophagy related 7; Atp5a1: ATP synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1; BL6: C57BL/6N mouse strain; BNIP3: BCL2/adenovirus E1B interacting protein 3; FCCP: carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; MAP1LC3A: microtubule-associated protein 1 light chain 3 alpha; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; mt-Atp8: mitochondrially encoded ATP synthase 8; MT-CO1: mitochondrially encoded cytochrome c oxidase I; MT-CO2: mitochondrially encoded cytochrome c oxidase II; mt-Co3: mitochondrially encoded cytochrome c oxidase III; mt-Cytb: mitochondrially encoded cytochrome b; mtDNA: mitochondrial DNA; MUL1: mitochondrial ubiquitin ligase activator of NFKB 1; nDNA: nuclear DNA; Ndufa9: NADH:ubiquinone oxireductase subunit A9; NDUFB8: NADH:ubiquinone oxireductase subunit B8; Nnt: nicotinamide nucleotide transhydrogenase; NZB: NZB/BINJ mouse strain; OXPHOS: oxidative phosphorylation; PINK1: PTEN induced putative kinase 1; Polg2: polymerase (DNA directed), gamma 2, accessory subunit; Ppara: peroxisome proliferator activated receptor alpha; Ppia: peptidylprolyl isomerase A; Prkn: parkin RBR E3 ubiquitin protein ligase; P10: post-natal day 10; P21: post-natal day 21; P100: post-natal day 100; qPCR: quantitative polymerase chain reaction; Rpl19: ribosomal protein L19; Rps18: ribosomal protein S18; SD: standard deviation; SEM: standard error of the mean; SDHB: succinate dehydrogenase complex, subunit B, iron sulfur (Ip); SQSTM1: sequestosome 1; Ssbp1: single-stranded DNA binding protein 1; TFAM: transcription factor A, mitochondrial; Tfb1m: transcription factor B1, mitochondrial; Tfb2m: transcription factor B2, mitochondrial; TOMM20: translocase of outer mitochondrial membrane 20; UQCRC2: ubiquinol cytochrome c reductase core protein 2; WT: wild-type.

Asunto(s)

Mitofagia , NADP Transhidrogenasas , Adenosina Trifosfato , Adulto , Animales , Apolipoproteínas/metabolismo , Apolipoproteínas B/metabolismo , Autofagia/genética , Dióxido de Carbono/metabolismo , Carbonil Cianuro p-Trifluorometoxifenil Hidrazona , Citocromos b/metabolismo , ADN Mitocondrial/genética , Proteínas de Unión al ADN/metabolismo , Complejo III de Transporte de Electrones , Complejo IV de Transporte de Electrones/metabolismo , Humanos , Hierro/metabolismo , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Proteínas Mitocondriales , NAD/metabolismo , NADP Transhidrogenasas/metabolismo , PPAR alfa/metabolismo , Isomerasa de Peptidilprolil/metabolismo , Proteínas Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteínas Ribosómicas/metabolismo , Proteína Sequestosoma-1/metabolismo , Succinato Deshidrogenasa/metabolismo , Azufre/metabolismo , Factores de Transcripción/metabolismo , Ubiquinona , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitinas/metabolismo

RESUMEN

KEY MESSAGE: The functional absence of the electron-transfer flavoprotein: ubiquinone oxidoreductase (ETFQO) directly impacts electrons donation to the mitochondrial electron transport chain under carbohydrate-limiting conditions without major impacts on the respiration of cell cultures. Alternative substrates (e.g., amino acids) can directly feed electrons into the mitochondrial electron transport chain (mETC) via the electron transfer flavoprotein/electron-transfer flavoprotein: ubiquinone oxidoreductase (ETF/ETFQO) complex, which supports plant respiration during stress situations. By using a cell culture system, here we investigated the responses of Arabidopsis thaliana mutants deficient in the expression of ETFQO (etfqo-1) following carbon limitation and supplied with amino acids. Our results demonstrate that isovaleryl-CoA dehydrogenase (IVDH) activity was induced during carbon limitation only in wild-type and that these changes occurred concomit with enhanced protein content. By contrast, neither the activity nor the total amount of IVDH was altered in etfqo-1 mutants. We also demonstrate that the activities of mitochondrial complexes in etfqo-1 mutants, display a similar pattern as in wild-type cells. Our findings suggest that the defect of ETFQO protein culminates with an impaired functioning of the IVDH, since no induction of IVDH activity was observed. However, the functional absence of the ETFQO seems not to cause major impacts on plant respiration under carbon limiting conditions, most likely due to other alternative electron entry pathways.

Asunto(s)

Proteínas de Arabidopsis , Arabidopsis , Flavoproteínas Transportadoras de Electrones , Aminoácidos de Cadena Ramificada/farmacología , Arabidopsis/citología , Arabidopsis/efectos de los fármacos , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Metabolismo de los Hidratos de Carbono , Técnicas de Cultivo de Célula , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Flavoproteínas Transportadoras de Electrones/genética , Flavoproteínas Transportadoras de Electrones/metabolismo , Regulación de la Expresión Génica de las Plantas , Isovaleril-CoA Deshidrogenasa/genética , Isovaleril-CoA Deshidrogenasa/metabolismo , Mitocondrias/genética , Mitocondrias/metabolismo , Mutación

RESUMEN

More than 100 years since the first description of Chagas Disease and with over 29,000 new cases annually due to vector transmission (in 2010), American Trypanosomiasis remains a Neglected Tropical Disease (NTD). This study presents the most comprehensive Trypanosoma cruzi sampling in terms of geographic locations and triatomine species analyzed to date and includes both nuclear and mitochondrial genomes. This addresses the gap of information from North and Central America. We incorporate new and previously published DNA sequence data from two mitochondrial genes, Cytochrome oxidase II (COII) and NADH dehydrogenase subunit 1 (ND1). These T. cruzi samples were collected over a broad geographic range including 111 parasite DNA samples extracted from triatomines newly collected across North and Central America, all of which were infected with T. cruzi in their natural environment. In addition, we present parasite reduced representation (Restriction site Associated DNA markers, RAD-tag) genomic nuclear data combined with the mitochondrial gene sequences for a subset of the triatomines (27 specimens) collected from Guatemala and El Salvador. Our mitochondrial phylogenetic reconstruction revealed two of the major mitochondrial lineages circulating across North and Central America, as well as the first ever mitochondrial data for TcBat from a triatomine collected in Central America. Our data also show that within mtTcIII, North and Central America represent an independent, distinct clade from South America, named here as mtTcIIINA-CA, geographically restricted to North and Central America. Lastly, the most frequent lineage detected across North and Central America, mtTcI, was also an independent, distinct clade from South America, noted as mtTcINA-CA. Furthermore, nuclear genome data based on Single Nucleotide Polymorphism (SNP) showed genetic structure of lineage TcI from specimens collected in Guatemala and El Salvador supporting the hypothesis that genetic diversity at a local scale has a geographical component. Our multiscale analysis contributes to the understanding of the independent and distinct evolution of T. cruzi lineages in North and Central America regions.

Asunto(s)

Enfermedad de Chagas/parasitología , Mitocondrias/genética , Trypanosoma cruzi/clasificación , Trypanosoma cruzi/aislamiento & purificación , América Central , Complejo I de Transporte de Electrón/genética , Complejo I de Transporte de Electrón/metabolismo , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Humanos , Mitocondrias/metabolismo , Filogenia , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , América del Sur , Trypanosoma cruzi/genética

RESUMEN

The species of the genus Potamolithus inhabiting the southwestern basin of the Andes are difficult to distinguish due to small size and similar shell morphology. Only Potamolithus australis and Potamolithus santiagensis have been traditionally recognized in this region, but the occurrence of several morphologically similar undescribed populations could increase the regional richness. Here we delimit described and potentially undescribed cryptic species of the genus using partial sequences of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Network analysis and diversity indices inferred six highly differentiated haplogroups, many of them sympatric and widespread in the study area. Phylogeographic analyses suggest a scenario of recent diversification and the occurrence of multiple refuges during the successive Pleistocene glaciations. Phylogenetic analysis also recovered six major clades that showed no relationship with physiography. Species delimitation analyses consistently recognized three or four candidate species apart from P. australis and P. santiagensis. Divergence times indicate that speciation of Chilean Potamolithus began at the end of the Pliocene, probably driven by climatic rather than geographic events. Considering the high inter- and intra-basin genetic diversity, conservation efforts should be focused on protecting sympatric taxa in the basins with the highest species richness.

Asunto(s)

Biodiversidad , Complejo IV de Transporte de Electrones/metabolismo , Gastrópodos/fisiología , Especiación Genética , Variación Genética , Filogeografía , Animales , Teorema de Bayes , Chile , ADN Mitocondrial/genética , Complejo IV de Transporte de Electrones/genética , Gastrópodos/clasificación , Mitocondrias/enzimología , Mitocondrias/genética

RESUMEN

We investigated the effects of acute and chronic exercise, prescribed in different intensity zones, but with total load-matched on mitochondrial markers (cytochrome C oxidase subunit IV (COX-IV), mitochondrial transcription factor A (Tfam), and citrate synthase (CS) activity in skeletal muscles, heart, and liver), glycogen stores, aerobic capacity, and anaerobic index in swimming rats. For this, 2 experimental designs were performed (acute and chronic efforts). Load-matched exercises were prescribed below, above, and on the anaerobic threshold (AnT), determined by the lactate minimum test. In chronic programs, 2 training prescription strategies were assessed (monotonous and linear periodized model). Results show changes in glycogen stores but no modification in the COX-IV and Tfam contents after acute exercises. In the chronic protocols, COX-IV and Tfam proteins and CS adaptations were intensity- and tissue-dependent. Monotonous training promoted better adaptations than the periodized model. Training at 80% of the AnT improved both performance variables, emphasizing the anaerobic index, concomitant to CS and COX-IV improvement (soleus muscle). The aerobic capacity and CS activity (gastrocnemius) were increased after 120% AnT training. In conclusion, acute exercise protocol did not promote responses in mitochondrial target proteins. An intensity and tissue dependence were reported in the chronic protocols, highlighting training at 80 and 120% of the AnT. Novelty: Load-matched acute exercise did not enhance COX-IV and Tfam contents in skeletal muscles, heart, and liver. In chronic exercise, COX-IV, Tfam, and CS activity adaptations were intensity- and tissue-dependent. Monotonous training was more efficient than the periodized linear model in adaptations of target proteins and enzymatic activity.

Asunto(s)

Mitocondrias Musculares/metabolismo , Músculo Esquelético/metabolismo , Biogénesis de Organelos , Condicionamiento Físico Animal , Adaptación Fisiológica , Umbral Anaerobio , Animales , Citrato (si)-Sintasa/metabolismo , Proteínas de Unión al ADN/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Glucógeno/metabolismo , Ácido Láctico/sangre , Masculino , Proteínas Mitocondriales/metabolismo , Ratas , Ratas Wistar , Factores de Transcripción/metabolismo

RESUMEN

AIMS: Homocysteine has been linked to neurodegeneration and motor function impairments. In the present study, we evaluate the effect of chronic mild hyperhomocysteinemia on the motor behavior (motor coordination, functional performance, and muscular force) and biochemical parameters (oxidative stress, energy metabolism, gene expression and/or protein abundance of cytokine related to the inflammatory pathways and acetylcholinesterase) in the striatum and cerebellum of Wistar male rats. MAIN METHODS: Rodents were submitted to one injection of homocysteine (0.03 µmol Hcy/g of body weight) between 30th and 60th postnatal days twice a day. After hyperhomocysteinemia induction, rats were submitted to horizontal ladder walking, beam balance, suspension, and vertical pole tests and/or euthanized to brain dissection for biochemical and molecular assays. KEY FINDINGS: Chronic mild hyperhomocysteinemia did not alter motor function, but induced oxidative stress and impaired mitochondrial complex IV activity in both structures. In the striatum, hyperhomocysteinemia decreased TNF-α gene expression and increased IL-1ß gene expression and acetylcholinesterase activity. In the cerebellum, hyperhomocysteinemia increased gene expression of TNF-α, IL-1ß, IL-10, and TGF-ß, while the acetylcholinesterase activity was decreased. In both structures, hyperhomocysteinemia decreased acetylcholinesterase protein abundance without altering total p-NF-κB, NF-κB, Nrf-2, and cleaved caspase-3. SIGNIFICANCE: Chronic mild hyperhomocysteinemia compromises several biochemical/molecular parameters, signaling pathways, oxidative stress, and chronic inflammation in the striatum and cerebellum of rats without impairing motor function. These alterations may be related to the mechanisms in which hyperhomocysteinemia has been linked to movement disorders later in life and neurodegeneration.

Asunto(s)

Cerebelo/patología , Cuerpo Estriado/patología , Citocinas/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Hiperhomocisteinemia/fisiopatología , Estrés Oxidativo , Animales , Cerebelo/metabolismo , Cuerpo Estriado/metabolismo , Citocinas/genética , Metabolismo Energético , Regulación de la Expresión Génica , Homocisteína/metabolismo , Masculino , Mitocondrias/metabolismo , Mitocondrias/patología , Ratas , Ratas Wistar

RESUMEN

Flight dispersal represents a key aspect of the evolutionary and ecological success of insects, allowing escape from predators, mating, and colonization of new niches. The huge energy demand posed by flight activity is essentially met by oxidative phosphorylation (OXPHOS) in flight muscle mitochondria. In insects, mitochondrial ATP supply and oxidant production are regulated by several factors, including the energy demand exerted by changes in adenylate balance. Indeed, adenylate directly regulates OXPHOS by targeting both chemiosmotic ATP production and the activities of specific mitochondrial enzymes. In several organisms, cytochrome c oxidase (COX) is regulated at transcriptional, post-translational, and allosteric levels, impacting mitochondrial energy metabolism, and redox balance. This review will present the concepts on how COX function contributes to flying insect biology, focusing on the existing examples in the literature where its structure and activity are regulated not only by physiological and environmental factors but also how changes in its activity impacts insect biology. We also performed in silico sequence analyses and determined the structure models of three COX subunits (IV, VIa, and VIc) from different insect species to compare with mammalian orthologs. We observed that the sequences and structure models of COXIV, COXVIa, and COXVIc were quite similar to their mammalian counterparts. Remarkably, specific substitutions to phosphomimetic amino acids at critical phosphorylation sites emerge as hallmarks on insect COX sequences, suggesting a new regulatory mechanism of COX activity. Therefore, by providing a physiological and bioenergetic framework of COX regulation in such metabolically extreme models, we hope to expand the knowledge of this critical enzyme complex and the potential consequences for insect dispersal.

Asunto(s)

Complejo IV de Transporte de Electrones/metabolismo , Animales , Insectos , Oxidación-Reducción , Fosforilación Oxidativa

RESUMEN

OBJECTIVE: The present study was designed to test the hypothesis that there is a reduction in the activity of the enzyme cytochrome c oxidase (Cox) in Alzheimer's disease (AD). METHODS: Systematic review of literature and meta-analysis were used with data obtained from the PubMed, Scopus, MEDLINE, Lilacs, Eric and Cochrane. The keywords were Alzheimer's AND Cox AND mitochondria; Alzheimer's AND Cox AND mitochondria; Alzheimer's AND complex IV AND mitochondria. A total of 1372 articles were found, 23 of them fitting the inclusion criteria. The data were assembled in an Excel spreadsheet and analysed using the RevMan software. A random effects model was adopted to the estimative of the effect. RESULTS: The data shows a significant decrease in the activity of the Cox AD patients and animal models. CONCLUSION: Cox enzyme may be an important molecular component involved in the mechanisms underlying AD. Therefore, this enzyme may represent a possible new biomarker for the disease as a complementary diagnosis and a new treatment target for AD.

Asunto(s)

Enfermedad de Alzheimer/enzimología , Complejo IV de Transporte de Electrones/metabolismo , Mitocondrias/enzimología , Enfermedad de Alzheimer/diagnóstico , Animales , Colorimetría/métodos , Humanos , Ratones , Mitocondrias/metabolismo , Modelos Animales , Polarografía/métodos , Ratas , Programas Informáticos , Espectrofotometría/métodos

RESUMEN

Pomegranate peel is an agro-industrial residue obtained after fruit processing with high total polyphenol (TP) content, making it an attractive by-product for its reuse. Pomegranate peel extract (PPE) and its bioactive compounds have shown positive effects on obesity models. Effects on favouring mitochondrial biogenesis and function have also been described. However, once phenolic compounds are extracted, their stability can be affected by diverse factors. Microencapsulation could improve PPE stability, allowing its incorporation into functional foods. Nevertheless, studies on the potential biological effects of PPE microparticles (MPPE) in obesity models are lacking. This study aims to evaluate the effect of MPPE on brown adipose tissue (BAT) mitochondrial structure and function and metabolic alterations related to obesity in mice fed a high-fat diet (HFD). PPE was microencapsulated by spray drying using inulin (IN) as a wall material and physically-chemically characterised. Eight-week-old male C57BL/6J mice (n 40) were randomly distributed into five groups: control diet (CD), HFD, HFD + IN, HFD + PPE (50 mg/kg per d TP) and HFD + MPPE (50 mg/kg per d TP), for 14 weeks. A glucose tolerance test and indirect calorimetry were conducted. Blood and adipose tissue samples were obtained. MPPE supplementation prevented HFD-induced body weight gain (P < 0·001), fasting glycaemia (P = 0·007) and total cholesterol rise (P = 0·001). MPPE resulted in higher BAT mitochondrial complex IV activity (P = 0·03) and prevented HFD-induced mitochondrial cristae alteration (P = 0·02). In conclusion, MPPE prevented HFD-induced excessive body weight gain and associated metabolic disturbances, potentially by activating complex IV activity and preserving mitochondrial cristae structure in BAT in mice fed with a HFD.

Asunto(s)

Tejido Adiposo Pardo/efectos de los fármacos , Dieta Alta en Grasa , Complejo IV de Transporte de Electrones/metabolismo , Mitocondrias/efectos de los fármacos , Extractos Vegetales , Granada (Fruta) , Animales , Masculino , Ratones , Ratones Endogámicos C57BL , Obesidad/prevención & control , Extractos Vegetales/farmacología , Polifenoles/farmacología , Aumento de Peso

RESUMEN

Several studies suggest that the assembly of mitochondrial respiratory complexes into structures known as supercomplexes (SCs) may increase the efficiency of the electron transport chain, reducing the rate of production of reactive oxygen species. Therefore, the study of the (dis)assembly of SCs may be relevant for the understanding of mitochondrial dysfunction reported in brain aging and major neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). Here we briefly reviewed the biogenesis and structural properties of SCs, the impact of mtDNA mutations and mitochondrial dynamics on SCs assembly, the role of lipids on stabilization of SCs and the methodological limitations for the study of SCs. More specifically, we summarized what is known about mitochondrial dysfunction and SCs organization and activity in aging, AD and PD. We focused on the critical variables to take into account when postmortem tissues are used to study the (dis)assembly of SCs. Since few works have been performed to study SCs in AD and PD, the impact of SCs dysfunction on the alteration of brain energetics in these diseases remains poorly understood. The convergence of future progress in the study of SCs structure at high resolution and the refinement of animal models of AD and PD, as well as the use of iPSC-based and somatic cell-derived neurons, will be critical in understanding the biological relevance of the structural remodeling of SCs.

Asunto(s)

Encéfalo/metabolismo , Metabolismo Energético/fisiología , Mitocondrias/metabolismo , Dinámicas Mitocondriales/fisiología , Enfermedades Neurodegenerativas/metabolismo , Neuronas/metabolismo , Envejecimiento/metabolismo , Envejecimiento/patología , Animales , Encéfalo/patología , Complejo I de Transporte de Electrón/genética , Complejo I de Transporte de Electrón/metabolismo , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Humanos , Mitocondrias/patología , Enfermedades Neurodegenerativas/patología , Neuronas/patología , Especies Reactivas de Oxígeno/metabolismo

RESUMEN

Obesity is characterized by chronic inflammation of low grade. The cholinergic anti-inflammatory pathway favors the reduction of the inflammatory response. In this work the effect of stimulation of the cholinergic anti-inflammatory pathway on SHIRPA behavioral test and mitochondrial respiratory chain activity in obese mice was evaluated. The animals were paired in four groups: saline + control diet; donepezil + control diet; saline + high-fat diet and donepezil + high-fat diet. 5 mg/kg/day orally of donepezil or saline were given 7 days before the beginning of the diet until completing 11 weeks of the experiment. Food intake and body weight were measured. At the end of the experiment the animals were submitted to the SHIRPA behavioral test, soon after they were killed by decapitation, the open abdominal cavity and the mesenteric fat were removed. The hypothalamus, hippocampus, prefrontal cortex, and striatum were removed for evaluation of the mitochondrial respiratory chain. It can be observed that donepezil prevented weight gain and food consumption, as well as a tendency to prevent the accumulation of mesenteric fat in obese animals. There was no behavioral change in obese animals, nor did the influence of donepezil on these parameters. On the other hand, donepezil did not prevent inhibition of complex I activity, prevented the inhibition of complex II, and showed a tendency to prevent IV complex activity inhibited in obesity. With these results it can be concluded that the activation of the cholinergic anti-inflammatory pathway is promising for the alterations found in obesity.

Asunto(s)

Fármacos Antiobesidad/uso terapéutico , Encéfalo/metabolismo , Donepezilo/uso terapéutico , Metabolismo Energético/efectos de los fármacos , Obesidad/prevención & control , Animales , Peso Corporal/efectos de los fármacos , Dieta Alta en Grasa , Complejo I de Transporte de Electrón/antagonistas & inhibidores , Complejo I de Transporte de Electrón/metabolismo , Complejo II de Transporte de Electrones/antagonistas & inhibidores , Complejo II de Transporte de Electrones/metabolismo , Complejo IV de Transporte de Electrones/antagonistas & inhibidores , Complejo IV de Transporte de Electrones/metabolismo , Masculino , Ratones , Obesidad/metabolismo

RESUMEN

The genetic diversity of Neotropical deer is increasingly jeopardized, owing to declining population size. Thus, the formation of cryobanking of somatic cells is important for the preservation of these species using cloning. The transformation of these cells into viable embryos has been hampered by a lack of endangered species oocytes. Accordingly, the aim of this study was to produce brown brocket deer embryos by interspecific somatic cell nuclear transfer (iSCNT), using goat or cattle oocytes as cytoplasts, and to elucidate embryo mitochondrial activity by measuring the expression levels of ATP6, COX3, and ND5. Cattle embryos produced by in vitro fertilization (IVF) were used as a control. There were no differences in the development of embryos produced by traditional SCNT and iSCNT when using either the goat cytoplasts (38.4% vs. 25.0% cleaved and 40.0% vs. 50.0% morula rates, respectively) or cattle cytoplast (72.8% vs. 65.5% cleaved and 11.3% vs. 5.9% blastocyst rates, respectively). Concerning the gene expression, no significant difference was observed when goat oocytes were used as cytoplasts. However, when using cattle oocytes and 16S as a reference gene, the iSCNT upregulated COX3, when compared with SCNT group. In contrast, when GAPDH was used as a reference gene, all the evaluated genes were upregulated in the iSCNT group, when compared with the IVF group. When compared with the SCNT group, only the expression of ATP6 was statistically different. In conclusion, it was demonstrated that interspecific nuclear transfer is a potentially useful tool for conservation programs of endangered similar deer species.

Asunto(s)

Ciervos/embriología , Ciervos/genética , Desarrollo Embrionario , Regulación del Desarrollo de la Expresión Génica , Genes Mitocondriales , Animales , Blastocisto/metabolismo , Bovinos , Células Cultivadas , Clonación de Organismos/veterinaria , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Embrión de Mamíferos/metabolismo , Femenino , Fertilización In Vitro , Cabras , ATPasas de Translocación de Protón Mitocondriales/genética , ATPasas de Translocación de Protón Mitocondriales/metabolismo , Mórula/metabolismo , NADH Deshidrogenasa/genética , NADH Deshidrogenasa/metabolismo , Técnicas de Transferencia Nuclear/veterinaria , Oocitos/metabolismo , Regulación hacia Arriba

RESUMEN

In the last years, clinical and preclinical researchers have increased their interest in non-psychotomimetic cannabinoids, like cannabidiol (CBD), as a strategy for treating psychostimulant use disorders. However, there are discrepancies in the pharmacological effects and brain targets of CBD. We evaluated if CBD was able to prevent the locomotor sensitization elicited by cocaine and caffeine co-administration. The effect of CBD on putative alterations in the metabolic activity of the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc), and its respective subregions (cingulated, prelimbic, and infralimbic cortices, and NAc core and shell) associated to the behavioral response, was also investigated. Rats were intraperitoneally and repeatedly treated with CBD (20 mg/kg) or its vehicle, followed by the combination of cocaine and caffeine (Coc+Caf; 5 mg/kg and 2.5 mg/kg, respectively) or saline for 3 days. After 5 days of withdrawal, all animals were challenged with Coc+Caf (day 9). Locomotor activity was automatically recorded and analyzed by a video-tracking software. The metabolic activity was determined by measuring cytochrome oxidase-I (CO-I) staining. Locomotion was significantly and similarly increased both in Veh-Coc+Caf- and CBD-Coc+Caf-treated animals during the pretreatment period (3 days); however, on day 9, the expression of the sensitization was blunted in CBD-treated animals. A hypoactive metabolic response and a hyperactive metabolic response in mPFC and NAc subregions respectively were observed after the behavioral sensitization. CBD prevented almost all these changes. Our findings substantially contribute to the understanding of the functional changes associated with cocaine- and caffeine-induced sensitization and the effect of CBD on this process.

Asunto(s)

Conducta Animal/efectos de los fármacos , Cafeína/toxicidad , Cannabidiol/farmacología , Estimulantes del Sistema Nervioso Central/toxicidad , Cocaína/toxicidad , Locomoción/efectos de los fármacos , Núcleo Accumbens/efectos de los fármacos , Corteza Prefrontal/efectos de los fármacos , Animales , Complejo IV de Transporte de Electrones/efectos de los fármacos , Complejo IV de Transporte de Electrones/metabolismo , Núcleo Accumbens/metabolismo , Corteza Prefrontal/metabolismo , Ratas

RESUMEN

Significance: Hypoxic-ischemic events due to intrapartum complications represent the second cause of neonatal mortality and initiate an acute brain disorder known as hypoxic-ischemic encephalopathy (HIE). In HIE, the brain undergoes primary and secondary energy failure phases separated by a latent phase in which partial neuronal recovery is observed. A hypoxic-ischemic event leads to oxygen restriction causing ATP depletion, neuronal oxidative stress, and cell death. Mitochondrial dysfunction and enhanced oxidant formation in brain cells are characteristic phenomena associated with energy failure. Recent Advances: Mitochondrial sources of oxidants in neurons include complex I of the mitochondrial respiratory chain, as a key contributor to O2•- production via succinate by a reverse electron transport mechanism. The reaction of O2•- with nitric oxide (•NO) yields peroxynitrite, a mitochondrial and cellular toxin. Quantitation of the redox state of cytochrome c oxidase, through broadband near-infrared spectroscopy, represents a promising monitoring approach to evaluate mitochondrial dysfunction in vivo in humans, in conjunction with the determination of cerebral oxygenation and their correlation with the severity of brain injury. Critical Issues: The energetic failure being a key phenomenon in HIE connected with the severity of the encephalopathy, measurement of mitochondrial dysfunction in vivo provides an approach to assess evolution, prognosis, and adequate therapies. Restoration of mitochondrial redox homeostasis constitutes a key therapeutic goal. Future Directions: While hypothermia is the only currently accepted therapy in clinical management to preserve mitochondrial function, other mitochondria-targeted and/or redox-based treatments are likely to synergize to ensure further efficacy.

Asunto(s)

Susceptibilidad a Enfermedades , Hipoxia-Isquemia Encefálica/etiología , Hipoxia-Isquemia Encefálica/metabolismo , Mitocondrias/metabolismo , Adenosina Trifosfato/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Homeostasis , Humanos , Hipoxia-Isquemia Encefálica/patología , Hipoxia-Isquemia Encefálica/fisiopatología , Neuronas/metabolismo , Oxidación-Reducción , Estrés Oxidativo

RESUMEN

Proinflammatory and inflammatory mediators induced by Trypanosoma cruzi infection increase the oxidative stress, generating toxicity for cells targeting mitochondria of different tissues. We studied the activity of citrate synthase and complexes I-IV of respiratory chain in mitochondria of blood lymphomonocyte fraction, from albino Swiss mice infected with different isolates of T. cruzi , during Chagas disease evolution. Complexes I-IV were modified in infected groups (p<0.05) in all the stages, and an inflammatory process of different magnitudes was detected in the heart and skeletal muscle according to the isolate. The citrate synthase activity presented modifications in the SGO Z12 and the Tulahuen group (p<0.05). Hearts showed fiber fragmentation and fibrosis; skeletal muscle presented inflammatory infiltrates and in the Tulahuen infected group, there were also amastigote nests. The inflammatory processes produced an oxidative stress that induced different alterations of mitochondrial enzymes activities in the lymphomonocyte fraction that can be detected by a simple blood extraction, suggesting that they could be used as disease markers, especially in the indeterminate phase of Chagas disease.

Asunto(s)

Enfermedad de Chagas/enzimología , Citrato (si)-Sintasa/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Mitocondrias/enzimología , Animales , Enfermedad de Chagas/metabolismo , Enfermedad de Chagas/fisiopatología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Masculino , Mitocondrias/parasitología , Mitocondrias/patología , Parasitemia

RESUMEN

The assembly of the CuA site in Cytochrome c Oxidase (COX) is a critical step for aerobic respiration in COX-dependent organisms. Several gene products have been associated with the assembly of this copper site, the most conserved of them belonging to the Sco family of proteins, which have been shown to perform different roles in different organisms. Plants express two orthologs of Sco proteins: Hcc1 and Hcc2. Hcc1 is known to be essential for plant development and for COX maturation, but its precise function has not been addressed until now. Here, we report the biochemical, structural and functional characterization of Arabidopsis thaliana Hcc1 protein (here renamed Sco1). We solved the crystal structure of the Cu+1 -bound soluble domain of this protein, revealing a tri coordinated environment involving a CxxxCxn H motif. We show that AtSco1 is able to work as a copper metallochaperone, inserting two Cu+1 ions into the CuA site in a model of CoxII. We also show that AtSco1 does not act as a thiol-disulfide oxido-reductase. Overall, this information sheds new light on the biochemistry of Sco proteins, highlighting the diversity of functions among them despite their high structural similarities. DATABASE: PDB entry 6N5U (Crystal structure of Arabidopsis thaliana ScoI with copper bound).

Asunto(s)

Proteínas de Arabidopsis/química , Arabidopsis/química , Proteínas Transportadoras de Cobre/química , Cobre/química , Complejo IV de Transporte de Electrones/química , Proteínas Mitocondriales/química , Chaperonas Moleculares/química , Secuencias de Aminoácidos , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Sitios de Unión , Clonación Molecular , Cobre/metabolismo , Proteínas Transportadoras de Cobre/genética , Proteínas Transportadoras de Cobre/metabolismo , Cristalografía por Rayos X , Complejo IV de Transporte de Electrones/genética , Complejo IV de Transporte de Electrones/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expresión Génica , Vectores Genéticos/química , Vectores Genéticos/metabolismo , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Modelos Moleculares , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Unión Proteica , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Thermus thermophilus/química